[PATCH v11 0/4] New debugfs API for capturing CRC of frames

[PATCH v11 0/4] New debugfs API for capturing CRC of frames

[Tomeu Vizoso]

Hi,

this series basically takes the facility for continuously capturing CRCs
of frames from the i915 driver and into the DRM core.

The idea is that test suites such as IGT use this information to check
that frames that are exected to be identical, also have identical CRC
values.

Other drivers for hardware that can provide frame CRCs (including eDP
panels that support self-refresh) can easily implement the new callback
and provide userspace with the CRC values.

Sorry about that, but there was a dangling brace in v10 breaking the build so
here is this v11.

Thanks,

Tomeu


Tomeu Vizoso (4):
  drm/i915/debugfs: Move out pipe CRC code
  drm: Add API for capturing frame CRCs
  drm/i915: Use new CRC debugfs API
  drm/i915: Put "cooked" vlank counters in frame CRC lines

 Documentation/gpu/drm-uapi.rst        |    6 +
 drivers/gpu/drm/Makefile              |    3 +-
 drivers/gpu/drm/drm_crtc.c            |   34 +-
 drivers/gpu/drm/drm_debugfs.c         |   34 +-
 drivers/gpu/drm/drm_debugfs_crc.c     |  351 ++++++++++++
 drivers/gpu/drm/drm_internal.h        |   16 +
 drivers/gpu/drm/i915/Makefile         |    2 +-
 drivers/gpu/drm/i915/i915_debugfs.c   |  886 +---------------------------
 drivers/gpu/drm/i915/i915_drv.h       |    1 +
 drivers/gpu/drm/i915/i915_irq.c       |   83 ++-
 drivers/gpu/drm/i915/intel_display.c  |    1 +
 drivers/gpu/drm/i915/intel_drv.h      |   13 +
 drivers/gpu/drm/i915/intel_pipe_crc.c | 1013 +++++++++++++++++++++++++++++++++
 include/drm/drm_crtc.h                |   41 ++
 include/drm/drm_debugfs_crc.h         |   73 +++
 15 files changed, 1645 insertions(+), 912 deletions(-)
 create mode 100644 drivers/gpu/drm/drm_debugfs_crc.c
 create mode 100644 drivers/gpu/drm/i915/intel_pipe_crc.c
 create mode 100644 include/drm/drm_debugfs_crc.h

-- 
2.7.4

[PATCH v11 1/4] drm/i915/debugfs: Move out pipe CRC code

[Tomeu Vizoso]

In preparation to using a generic API in the DRM core for continuous CRC
generation, move the related code out of i915_debugfs.c into a new file.

Eventually, only the Intel-specific code will remain in this new file.

v2: Rebased.

v6: Rebased.

v7: Fix whitespace issue.

v9: Have intel_display_crc_init accept a drm_i915_private instead.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
---

 drivers/gpu/drm/i915/Makefile         |   2 +-
 drivers/gpu/drm/i915/i915_debugfs.c   | 886 +-------------------------------
 drivers/gpu/drm/i915/intel_drv.h      |   5 +
 drivers/gpu/drm/i915/intel_pipe_crc.c | 943 ++++++++++++++++++++++++++++++++++
 4 files changed, 953 insertions(+), 883 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/intel_pipe_crc.c

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index a998c2bce70a..e6fe0040fe64 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -24,7 +24,7 @@ i915-y := i915_drv.o \
 	  intel_runtime_pm.o
 
 i915-$(CONFIG_COMPAT)   += i915_ioc32.o
-i915-$(CONFIG_DEBUG_FS) += i915_debugfs.o
+i915-$(CONFIG_DEBUG_FS) += i915_debugfs.o intel_pipe_crc.o
 
 # GEM code
 i915-y += i915_cmd_parser.o \
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index da7141382b00..4fb9d829884e 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -26,19 +26,9 @@
  *
  */
 
-#include <linux/seq_file.h>
-#include <linux/circ_buf.h>
-#include <linux/ctype.h>
 #include <linux/debugfs.h>
-#include <linux/slab.h>
-#include <linux/export.h>
 #include <linux/list_sort.h>
-#include <asm/msr-index.h>
-#include <drm/drmP.h>
 #include "intel_drv.h"
-#include "intel_ringbuffer.h"
-#include <drm/i915_drm.h>
-#include "i915_drv.h"
 
 static inline struct drm_i915_private *node_to_i915(struct drm_info_node *node)
 {
@@ -3414,12 +3404,6 @@ static int i915_drrs_status(struct seq_file *m, void *unused)
 	return 0;
 }
 
-struct pipe_crc_info {
-	const char *name;
-	struct drm_i915_private *dev_priv;
-	enum pipe pipe;
-};
-
 static int i915_dp_mst_info(struct seq_file *m, void *unused)
 {
 	struct drm_i915_private *dev_priv = node_to_i915(m->private);
@@ -3449,848 +3433,6 @@ static int i915_dp_mst_info(struct seq_file *m, void *unused)
 	return 0;
 }
 
-static int i915_pipe_crc_open(struct inode *inode, struct file *filep)
-{
-	struct pipe_crc_info *info = inode->i_private;
-	struct drm_i915_private *dev_priv = info->dev_priv;
-	struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[info->pipe];
-
-	if (info->pipe >= INTEL_INFO(dev_priv)->num_pipes)
-		return -ENODEV;
-
-	spin_lock_irq(&pipe_crc->lock);
-
-	if (pipe_crc->opened) {
-		spin_unlock_irq(&pipe_crc->lock);
-		return -EBUSY; /* already open */
-	}
-
-	pipe_crc->opened = true;
-	filep->private_data = inode->i_private;
-
-	spin_unlock_irq(&pipe_crc->lock);
-
-	return 0;
-}
-
-static int i915_pipe_crc_release(struct inode *inode, struct file *filep)
-{
-	struct pipe_crc_info *info = inode->i_private;
-	struct drm_i915_private *dev_priv = info->dev_priv;
-	struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[info->pipe];
-
-	spin_lock_irq(&pipe_crc->lock);
-	pipe_crc->opened = false;
-	spin_unlock_irq(&pipe_crc->lock);
-
-	return 0;
-}
-
-/* (6 fields, 8 chars each, space separated (5) + '\n') */
-#define PIPE_CRC_LINE_LEN	(6 * 8 + 5 + 1)
-/* account for \'0' */
-#define PIPE_CRC_BUFFER_LEN	(PIPE_CRC_LINE_LEN + 1)
-
-static int pipe_crc_data_count(struct intel_pipe_crc *pipe_crc)
-{
-	assert_spin_locked(&pipe_crc->lock);
-	return CIRC_CNT(pipe_crc->head, pipe_crc->tail,
-			INTEL_PIPE_CRC_ENTRIES_NR);
-}
-
-static ssize_t
-i915_pipe_crc_read(struct file *filep, char __user *user_buf, size_t count,
-		   loff_t *pos)
-{
-	struct pipe_crc_info *info = filep->private_data;
-	struct drm_i915_private *dev_priv = info->dev_priv;
-	struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[info->pipe];
-	char buf[PIPE_CRC_BUFFER_LEN];
-	int n_entries;
-	ssize_t bytes_read;
-
-	/*
-	 * Don't allow user space to provide buffers not big enough to hold
-	 * a line of data.
-	 */
-	if (count < PIPE_CRC_LINE_LEN)
-		return -EINVAL;
-
-	if (pipe_crc->source == INTEL_PIPE_CRC_SOURCE_NONE)
-		return 0;
-
-	/* nothing to read */
-	spin_lock_irq(&pipe_crc->lock);
-	while (pipe_crc_data_count(pipe_crc) == 0) {
-		int ret;
-
-		if (filep->f_flags & O_NONBLOCK) {
-			spin_unlock_irq(&pipe_crc->lock);
-			return -EAGAIN;
-		}
-
-		ret = wait_event_interruptible_lock_irq(pipe_crc->wq,
-				pipe_crc_data_count(pipe_crc), pipe_crc->lock);
-		if (ret) {
-			spin_unlock_irq(&pipe_crc->lock);
-			return ret;
-		}
-	}
-
-	/* We now have one or more entries to read */
-	n_entries = count / PIPE_CRC_LINE_LEN;
-
-	bytes_read = 0;
-	while (n_entries > 0) {
-		struct intel_pipe_crc_entry *entry =
-			&pipe_crc->entries[pipe_crc->tail];
-
-		if (CIRC_CNT(pipe_crc->head, pipe_crc->tail,
-			     INTEL_PIPE_CRC_ENTRIES_NR) < 1)
-			break;
-
-		BUILD_BUG_ON_NOT_POWER_OF_2(INTEL_PIPE_CRC_ENTRIES_NR);
-		pipe_crc->tail = (pipe_crc->tail + 1) & (INTEL_PIPE_CRC_ENTRIES_NR - 1);
-
-		bytes_read += snprintf(buf, PIPE_CRC_BUFFER_LEN,
-				       "%8u %8x %8x %8x %8x %8x\n",
-				       entry->frame, entry->crc[0],
-				       entry->crc[1], entry->crc[2],
-				       entry->crc[3], entry->crc[4]);
-
-		spin_unlock_irq(&pipe_crc->lock);
-
-		if (copy_to_user(user_buf, buf, PIPE_CRC_LINE_LEN))
-			return -EFAULT;
-
-		user_buf += PIPE_CRC_LINE_LEN;
-		n_entries--;
-
-		spin_lock_irq(&pipe_crc->lock);
-	}
-
-	spin_unlock_irq(&pipe_crc->lock);
-
-	return bytes_read;
-}
-
-static const struct file_operations i915_pipe_crc_fops = {
-	.owner = THIS_MODULE,
-	.open = i915_pipe_crc_open,
-	.read = i915_pipe_crc_read,
-	.release = i915_pipe_crc_release,
-};
-
-static struct pipe_crc_info i915_pipe_crc_data[I915_MAX_PIPES] = {
-	{
-		.name = "i915_pipe_A_crc",
-		.pipe = PIPE_A,
-	},
-	{
-		.name = "i915_pipe_B_crc",
-		.pipe = PIPE_B,
-	},
-	{
-		.name = "i915_pipe_C_crc",
-		.pipe = PIPE_C,
-	},
-};
-
-static int i915_pipe_crc_create(struct dentry *root, struct drm_minor *minor,
-				enum pipe pipe)
-{
-	struct drm_i915_private *dev_priv = to_i915(minor->dev);
-	struct dentry *ent;
-	struct pipe_crc_info *info = &i915_pipe_crc_data[pipe];
-
-	info->dev_priv = dev_priv;
-	ent = debugfs_create_file(info->name, S_IRUGO, root, info,
-				  &i915_pipe_crc_fops);
-	if (!ent)
-		return -ENOMEM;
-
-	return drm_add_fake_info_node(minor, ent, info);
-}
-
-static const char * const pipe_crc_sources[] = {
-	"none",
-	"plane1",
-	"plane2",
-	"pf",
-	"pipe",
-	"TV",
-	"DP-B",
-	"DP-C",
-	"DP-D",
-	"auto",
-};
-
-static const char *pipe_crc_source_name(enum intel_pipe_crc_source source)
-{
-	BUILD_BUG_ON(ARRAY_SIZE(pipe_crc_sources) != INTEL_PIPE_CRC_SOURCE_MAX);
-	return pipe_crc_sources[source];
-}
-
-static int display_crc_ctl_show(struct seq_file *m, void *data)
-{
-	struct drm_i915_private *dev_priv = m->private;
-	int i;
-
-	for (i = 0; i < I915_MAX_PIPES; i++)
-		seq_printf(m, "%c %s\n", pipe_name(i),
-			   pipe_crc_source_name(dev_priv->pipe_crc[i].source));
-
-	return 0;
-}
-
-static int display_crc_ctl_open(struct inode *inode, struct file *file)
-{
-	return single_open(file, display_crc_ctl_show, inode->i_private);
-}
-
-static int i8xx_pipe_crc_ctl_reg(enum intel_pipe_crc_source *source,
-				 uint32_t *val)
-{
-	if (*source == INTEL_PIPE_CRC_SOURCE_AUTO)
-		*source = INTEL_PIPE_CRC_SOURCE_PIPE;
-
-	switch (*source) {
-	case INTEL_PIPE_CRC_SOURCE_PIPE:
-		*val = PIPE_CRC_ENABLE | PIPE_CRC_INCLUDE_BORDER_I8XX;
-		break;
-	case INTEL_PIPE_CRC_SOURCE_NONE:
-		*val = 0;
-		break;
-	default:
-		return -EINVAL;
-	}
-
-	return 0;
-}
-
-static int i9xx_pipe_crc_auto_source(struct drm_i915_private *dev_priv,
-				     enum pipe pipe,
-				     enum intel_pipe_crc_source *source)
-{
-	struct drm_device *dev = &dev_priv->drm;
-	struct intel_encoder *encoder;
-	struct intel_crtc *crtc;
-	struct intel_digital_port *dig_port;
-	int ret = 0;
-
-	*source = INTEL_PIPE_CRC_SOURCE_PIPE;
-
-	drm_modeset_lock_all(dev);
-	for_each_intel_encoder(dev, encoder) {
-		if (!encoder->base.crtc)
-			continue;
-
-		crtc = to_intel_crtc(encoder->base.crtc);
-
-		if (crtc->pipe != pipe)
-			continue;
-
-		switch (encoder->type) {
-		case INTEL_OUTPUT_TVOUT:
-			*source = INTEL_PIPE_CRC_SOURCE_TV;
-			break;
-		case INTEL_OUTPUT_DP:
-		case INTEL_OUTPUT_EDP:
-			dig_port = enc_to_dig_port(&encoder->base);
-			switch (dig_port->port) {
-			case PORT_B:
-				*source = INTEL_PIPE_CRC_SOURCE_DP_B;
-				break;
-			case PORT_C:
-				*source = INTEL_PIPE_CRC_SOURCE_DP_C;
-				break;
-			case PORT_D:
-				*source = INTEL_PIPE_CRC_SOURCE_DP_D;
-				break;
-			default:
-				WARN(1, "nonexisting DP port %c\n",
-				     port_name(dig_port->port));
-				break;
-			}
-			break;
-		default:
-			break;
-		}
-	}
-	drm_modeset_unlock_all(dev);
-
-	return ret;
-}
-
-static int vlv_pipe_crc_ctl_reg(struct drm_i915_private *dev_priv,
-				enum pipe pipe,
-				enum intel_pipe_crc_source *source,
-				uint32_t *val)
-{
-	bool need_stable_symbols = false;
-
-	if (*source == INTEL_PIPE_CRC_SOURCE_AUTO) {
-		int ret = i9xx_pipe_crc_auto_source(dev_priv, pipe, source);
-		if (ret)
-			return ret;
-	}
-
-	switch (*source) {
-	case INTEL_PIPE_CRC_SOURCE_PIPE:
-		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_PIPE_VLV;
-		break;
-	case INTEL_PIPE_CRC_SOURCE_DP_B:
-		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_DP_B_VLV;
-		need_stable_symbols = true;
-		break;
-	case INTEL_PIPE_CRC_SOURCE_DP_C:
-		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_DP_C_VLV;
-		need_stable_symbols = true;
-		break;
-	case INTEL_PIPE_CRC_SOURCE_DP_D:
-		if (!IS_CHERRYVIEW(dev_priv))
-			return -EINVAL;
-		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_DP_D_VLV;
-		need_stable_symbols = true;
-		break;
-	case INTEL_PIPE_CRC_SOURCE_NONE:
-		*val = 0;
-		break;
-	default:
-		return -EINVAL;
-	}
-
-	/*
-	 * When the pipe CRC tap point is after the transcoders we need
-	 * to tweak symbol-level features to produce a deterministic series of
-	 * symbols for a given frame. We need to reset those features only once
-	 * a frame (instead of every nth symbol):
-	 *   - DC-balance: used to ensure a better clock recovery from the data
-	 *     link (SDVO)
-	 *   - DisplayPort scrambling: used for EMI reduction
-	 */
-	if (need_stable_symbols) {
-		uint32_t tmp = I915_READ(PORT_DFT2_G4X);
-
-		tmp |= DC_BALANCE_RESET_VLV;
-		switch (pipe) {
-		case PIPE_A:
-			tmp |= PIPE_A_SCRAMBLE_RESET;
-			break;
-		case PIPE_B:
-			tmp |= PIPE_B_SCRAMBLE_RESET;
-			break;
-		case PIPE_C:
-			tmp |= PIPE_C_SCRAMBLE_RESET;
-			break;
-		default:
-			return -EINVAL;
-		}
-		I915_WRITE(PORT_DFT2_G4X, tmp);
-	}
-
-	return 0;
-}
-
-static int i9xx_pipe_crc_ctl_reg(struct drm_i915_private *dev_priv,
-				 enum pipe pipe,
-				 enum intel_pipe_crc_source *source,
-				 uint32_t *val)
-{
-	bool need_stable_symbols = false;
-
-	if (*source == INTEL_PIPE_CRC_SOURCE_AUTO) {
-		int ret = i9xx_pipe_crc_auto_source(dev_priv, pipe, source);
-		if (ret)
-			return ret;
-	}
-
-	switch (*source) {
-	case INTEL_PIPE_CRC_SOURCE_PIPE:
-		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_PIPE_I9XX;
-		break;
-	case INTEL_PIPE_CRC_SOURCE_TV:
-		if (!SUPPORTS_TV(dev_priv))
-			return -EINVAL;
-		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_TV_PRE;
-		break;
-	case INTEL_PIPE_CRC_SOURCE_DP_B:
-		if (!IS_G4X(dev_priv))
-			return -EINVAL;
-		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_DP_B_G4X;
-		need_stable_symbols = true;
-		break;
-	case INTEL_PIPE_CRC_SOURCE_DP_C:
-		if (!IS_G4X(dev_priv))
-			return -EINVAL;
-		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_DP_C_G4X;
-		need_stable_symbols = true;
-		break;
-	case INTEL_PIPE_CRC_SOURCE_DP_D:
-		if (!IS_G4X(dev_priv))
-			return -EINVAL;
-		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_DP_D_G4X;
-		need_stable_symbols = true;
-		break;
-	case INTEL_PIPE_CRC_SOURCE_NONE:
-		*val = 0;
-		break;
-	default:
-		return -EINVAL;
-	}
-
-	/*
-	 * When the pipe CRC tap point is after the transcoders we need
-	 * to tweak symbol-level features to produce a deterministic series of
-	 * symbols for a given frame. We need to reset those features only once
-	 * a frame (instead of every nth symbol):
-	 *   - DC-balance: used to ensure a better clock recovery from the data
-	 *     link (SDVO)
-	 *   - DisplayPort scrambling: used for EMI reduction
-	 */
-	if (need_stable_symbols) {
-		uint32_t tmp = I915_READ(PORT_DFT2_G4X);
-
-		WARN_ON(!IS_G4X(dev_priv));
-
-		I915_WRITE(PORT_DFT_I9XX,
-			   I915_READ(PORT_DFT_I9XX) | DC_BALANCE_RESET);
-
-		if (pipe == PIPE_A)
-			tmp |= PIPE_A_SCRAMBLE_RESET;
-		else
-			tmp |= PIPE_B_SCRAMBLE_RESET;
-
-		I915_WRITE(PORT_DFT2_G4X, tmp);
-	}
-
-	return 0;
-}
-
-static void vlv_undo_pipe_scramble_reset(struct drm_i915_private *dev_priv,
-					 enum pipe pipe)
-{
-	uint32_t tmp = I915_READ(PORT_DFT2_G4X);
-
-	switch (pipe) {
-	case PIPE_A:
-		tmp &= ~PIPE_A_SCRAMBLE_RESET;
-		break;
-	case PIPE_B:
-		tmp &= ~PIPE_B_SCRAMBLE_RESET;
-		break;
-	case PIPE_C:
-		tmp &= ~PIPE_C_SCRAMBLE_RESET;
-		break;
-	default:
-		return;
-	}
-	if (!(tmp & PIPE_SCRAMBLE_RESET_MASK))
-		tmp &= ~DC_BALANCE_RESET_VLV;
-	I915_WRITE(PORT_DFT2_G4X, tmp);
-
-}
-
-static void g4x_undo_pipe_scramble_reset(struct drm_i915_private *dev_priv,
-					 enum pipe pipe)
-{
-	uint32_t tmp = I915_READ(PORT_DFT2_G4X);
-
-	if (pipe == PIPE_A)
-		tmp &= ~PIPE_A_SCRAMBLE_RESET;
-	else
-		tmp &= ~PIPE_B_SCRAMBLE_RESET;
-	I915_WRITE(PORT_DFT2_G4X, tmp);
-
-	if (!(tmp & PIPE_SCRAMBLE_RESET_MASK)) {
-		I915_WRITE(PORT_DFT_I9XX,
-			   I915_READ(PORT_DFT_I9XX) & ~DC_BALANCE_RESET);
-	}
-}
-
-static int ilk_pipe_crc_ctl_reg(enum intel_pipe_crc_source *source,
-				uint32_t *val)
-{
-	if (*source == INTEL_PIPE_CRC_SOURCE_AUTO)
-		*source = INTEL_PIPE_CRC_SOURCE_PIPE;
-
-	switch (*source) {
-	case INTEL_PIPE_CRC_SOURCE_PLANE1:
-		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_PRIMARY_ILK;
-		break;
-	case INTEL_PIPE_CRC_SOURCE_PLANE2:
-		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_SPRITE_ILK;
-		break;
-	case INTEL_PIPE_CRC_SOURCE_PIPE:
-		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_PIPE_ILK;
-		break;
-	case INTEL_PIPE_CRC_SOURCE_NONE:
-		*val = 0;
-		break;
-	default:
-		return -EINVAL;
-	}
-
-	return 0;
-}
-
-static void hsw_trans_edp_pipe_A_crc_wa(struct drm_i915_private *dev_priv,
-					bool enable)
-{
-	struct drm_device *dev = &dev_priv->drm;
-	struct intel_crtc *crtc =
-		to_intel_crtc(dev_priv->pipe_to_crtc_mapping[PIPE_A]);
-	struct intel_crtc_state *pipe_config;
-	struct drm_atomic_state *state;
-	int ret = 0;
-
-	drm_modeset_lock_all(dev);
-	state = drm_atomic_state_alloc(dev);
-	if (!state) {
-		ret = -ENOMEM;
-		goto out;
-	}
-
-	state->acquire_ctx = drm_modeset_legacy_acquire_ctx(&crtc->base);
-	pipe_config = intel_atomic_get_crtc_state(state, crtc);
-	if (IS_ERR(pipe_config)) {
-		ret = PTR_ERR(pipe_config);
-		goto out;
-	}
-
-	pipe_config->pch_pfit.force_thru = enable;
-	if (pipe_config->cpu_transcoder == TRANSCODER_EDP &&
-	    pipe_config->pch_pfit.enabled != enable)
-		pipe_config->base.connectors_changed = true;
-
-	ret = drm_atomic_commit(state);
-out:
-	drm_modeset_unlock_all(dev);
-	WARN(ret, "Toggling workaround to %i returns %i\n", enable, ret);
-	if (ret)
-		drm_atomic_state_free(state);
-}
-
-static int ivb_pipe_crc_ctl_reg(struct drm_i915_private *dev_priv,
-				enum pipe pipe,
-				enum intel_pipe_crc_source *source,
-				uint32_t *val)
-{
-	if (*source == INTEL_PIPE_CRC_SOURCE_AUTO)
-		*source = INTEL_PIPE_CRC_SOURCE_PF;
-
-	switch (*source) {
-	case INTEL_PIPE_CRC_SOURCE_PLANE1:
-		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_PRIMARY_IVB;
-		break;
-	case INTEL_PIPE_CRC_SOURCE_PLANE2:
-		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_SPRITE_IVB;
-		break;
-	case INTEL_PIPE_CRC_SOURCE_PF:
-		if (IS_HASWELL(dev_priv) && pipe == PIPE_A)
-			hsw_trans_edp_pipe_A_crc_wa(dev_priv, true);
-
-		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_PF_IVB;
-		break;
-	case INTEL_PIPE_CRC_SOURCE_NONE:
-		*val = 0;
-		break;
-	default:
-		return -EINVAL;
-	}
-
-	return 0;
-}
-
-static int pipe_crc_set_source(struct drm_i915_private *dev_priv,
-			       enum pipe pipe,
-			       enum intel_pipe_crc_source source)
-{
-	struct drm_device *dev = &dev_priv->drm;
-	struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[pipe];
-	struct intel_crtc *crtc =
-			to_intel_crtc(intel_get_crtc_for_pipe(dev, pipe));
-	enum intel_display_power_domain power_domain;
-	u32 val = 0; /* shut up gcc */
-	int ret;
-
-	if (pipe_crc->source == source)
-		return 0;
-
-	/* forbid changing the source without going back to 'none' */
-	if (pipe_crc->source && source)
-		return -EINVAL;
-
-	power_domain = POWER_DOMAIN_PIPE(pipe);
-	if (!intel_display_power_get_if_enabled(dev_priv, power_domain)) {
-		DRM_DEBUG_KMS("Trying to capture CRC while pipe is off\n");
-		return -EIO;
-	}
-
-	if (IS_GEN2(dev_priv))
-		ret = i8xx_pipe_crc_ctl_reg(&source, &val);
-	else if (INTEL_GEN(dev_priv) < 5)
-		ret = i9xx_pipe_crc_ctl_reg(dev_priv, pipe, &source, &val);
-	else if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
-		ret = vlv_pipe_crc_ctl_reg(dev_priv, pipe, &source, &val);
-	else if (IS_GEN5(dev_priv) || IS_GEN6(dev_priv))
-		ret = ilk_pipe_crc_ctl_reg(&source, &val);
-	else
-		ret = ivb_pipe_crc_ctl_reg(dev_priv, pipe, &source, &val);
-
-	if (ret != 0)
-		goto out;
-
-	/* none -> real source transition */
-	if (source) {
-		struct intel_pipe_crc_entry *entries;
-
-		DRM_DEBUG_DRIVER("collecting CRCs for pipe %c, %s\n",
-				 pipe_name(pipe), pipe_crc_source_name(source));
-
-		entries = kcalloc(INTEL_PIPE_CRC_ENTRIES_NR,
-				  sizeof(pipe_crc->entries[0]),
-				  GFP_KERNEL);
-		if (!entries) {
-			ret = -ENOMEM;
-			goto out;
-		}
-
-		/*
-		 * When IPS gets enabled, the pipe CRC changes. Since IPS gets
-		 * enabled and disabled dynamically based on package C states,
-		 * user space can't make reliable use of the CRCs, so let's just
-		 * completely disable it.
-		 */
-		hsw_disable_ips(crtc);
-
-		spin_lock_irq(&pipe_crc->lock);
-		kfree(pipe_crc->entries);
-		pipe_crc->entries = entries;
-		pipe_crc->head = 0;
-		pipe_crc->tail = 0;
-		spin_unlock_irq(&pipe_crc->lock);
-	}
-
-	pipe_crc->source = source;
-
-	I915_WRITE(PIPE_CRC_CTL(pipe), val);
-	POSTING_READ(PIPE_CRC_CTL(pipe));
-
-	/* real source -> none transition */
-	if (source == INTEL_PIPE_CRC_SOURCE_NONE) {
-		struct intel_pipe_crc_entry *entries;
-		struct intel_crtc *crtc =
-			to_intel_crtc(dev_priv->pipe_to_crtc_mapping[pipe]);
-
-		DRM_DEBUG_DRIVER("stopping CRCs for pipe %c\n",
-				 pipe_name(pipe));
-
-		drm_modeset_lock(&crtc->base.mutex, NULL);
-		if (crtc->base.state->active)
-			intel_wait_for_vblank(dev, pipe);
-		drm_modeset_unlock(&crtc->base.mutex);
-
-		spin_lock_irq(&pipe_crc->lock);
-		entries = pipe_crc->entries;
-		pipe_crc->entries = NULL;
-		pipe_crc->head = 0;
-		pipe_crc->tail = 0;
-		spin_unlock_irq(&pipe_crc->lock);
-
-		kfree(entries);
-
-		if (IS_G4X(dev_priv))
-			g4x_undo_pipe_scramble_reset(dev_priv, pipe);
-		else if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
-			vlv_undo_pipe_scramble_reset(dev_priv, pipe);
-		else if (IS_HASWELL(dev_priv) && pipe == PIPE_A)
-			hsw_trans_edp_pipe_A_crc_wa(dev_priv, false);
-
-		hsw_enable_ips(crtc);
-	}
-
-	ret = 0;
-
-out:
-	intel_display_power_put(dev_priv, power_domain);
-
-	return ret;
-}
-
-/*
- * Parse pipe CRC command strings:
- *   command: wsp* object wsp+ name wsp+ source wsp*
- *   object: 'pipe'
- *   name: (A | B | C)
- *   source: (none | plane1 | plane2 | pf)
- *   wsp: (#0x20 | #0x9 | #0xA)+
- *
- * eg.:
- *  "pipe A plane1"  ->  Start CRC computations on plane1 of pipe A
- *  "pipe A none"    ->  Stop CRC
- */
-static int display_crc_ctl_tokenize(char *buf, char *words[], int max_words)
-{
-	int n_words = 0;
-
-	while (*buf) {
-		char *end;
-
-		/* skip leading white space */
-		buf = skip_spaces(buf);
-		if (!*buf)
-			break;	/* end of buffer */
-
-		/* find end of word */
-		for (end = buf; *end && !isspace(*end); end++)
-			;
-
-		if (n_words == max_words) {
-			DRM_DEBUG_DRIVER("too many words, allowed <= %d\n",
-					 max_words);
-			return -EINVAL;	/* ran out of words[] before bytes */
-		}
-
-		if (*end)
-			*end++ = '\0';
-		words[n_words++] = buf;
-		buf = end;
-	}
-
-	return n_words;
-}
-
-enum intel_pipe_crc_object {
-	PIPE_CRC_OBJECT_PIPE,
-};
-
-static const char * const pipe_crc_objects[] = {
-	"pipe",
-};
-
-static int
-display_crc_ctl_parse_object(const char *buf, enum intel_pipe_crc_object *o)
-{
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(pipe_crc_objects); i++)
-		if (!strcmp(buf, pipe_crc_objects[i])) {
-			*o = i;
-			return 0;
-		    }
-
-	return -EINVAL;
-}
-
-static int display_crc_ctl_parse_pipe(const char *buf, enum pipe *pipe)
-{
-	const char name = buf[0];
-
-	if (name < 'A' || name >= pipe_name(I915_MAX_PIPES))
-		return -EINVAL;
-
-	*pipe = name - 'A';
-
-	return 0;
-}
-
-static int
-display_crc_ctl_parse_source(const char *buf, enum intel_pipe_crc_source *s)
-{
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(pipe_crc_sources); i++)
-		if (!strcmp(buf, pipe_crc_sources[i])) {
-			*s = i;
-			return 0;
-		    }
-
-	return -EINVAL;
-}
-
-static int display_crc_ctl_parse(struct drm_i915_private *dev_priv,
-				 char *buf, size_t len)
-{
-#define N_WORDS 3
-	int n_words;
-	char *words[N_WORDS];
-	enum pipe pipe;
-	enum intel_pipe_crc_object object;
-	enum intel_pipe_crc_source source;
-
-	n_words = display_crc_ctl_tokenize(buf, words, N_WORDS);
-	if (n_words != N_WORDS) {
-		DRM_DEBUG_DRIVER("tokenize failed, a command is %d words\n",
-				 N_WORDS);
-		return -EINVAL;
-	}
-
-	if (display_crc_ctl_parse_object(words[0], &object) < 0) {
-		DRM_DEBUG_DRIVER("unknown object %s\n", words[0]);
-		return -EINVAL;
-	}
-
-	if (display_crc_ctl_parse_pipe(words[1], &pipe) < 0) {
-		DRM_DEBUG_DRIVER("unknown pipe %s\n", words[1]);
-		return -EINVAL;
-	}
-
-	if (display_crc_ctl_parse_source(words[2], &source) < 0) {
-		DRM_DEBUG_DRIVER("unknown source %s\n", words[2]);
-		return -EINVAL;
-	}
-
-	return pipe_crc_set_source(dev_priv, pipe, source);
-}
-
-static ssize_t display_crc_ctl_write(struct file *file, const char __user *ubuf,
-				     size_t len, loff_t *offp)
-{
-	struct seq_file *m = file->private_data;
-	struct drm_i915_private *dev_priv = m->private;
-	char *tmpbuf;
-	int ret;
-
-	if (len == 0)
-		return 0;
-
-	if (len > PAGE_SIZE - 1) {
-		DRM_DEBUG_DRIVER("expected <%lu bytes into pipe crc control\n",
-				 PAGE_SIZE);
-		return -E2BIG;
-	}
-
-	tmpbuf = kmalloc(len + 1, GFP_KERNEL);
-	if (!tmpbuf)
-		return -ENOMEM;
-
-	if (copy_from_user(tmpbuf, ubuf, len)) {
-		ret = -EFAULT;
-		goto out;
-	}
-	tmpbuf[len] = '\0';
-
-	ret = display_crc_ctl_parse(dev_priv, tmpbuf, len);
-
-out:
-	kfree(tmpbuf);
-	if (ret < 0)
-		return ret;
-
-	*offp += len;
-	return len;
-}
-
-static const struct file_operations i915_display_crc_ctl_fops = {
-	.owner = THIS_MODULE,
-	.open = display_crc_ctl_open,
-	.read = seq_read,
-	.llseek = seq_lseek,
-	.release = single_release,
-	.write = display_crc_ctl_write
-};
-
 static ssize_t i915_displayport_test_active_write(struct file *file,
 						  const char __user *ubuf,
 						  size_t len, loff_t *offp)
@@ -5345,19 +4487,6 @@ static const struct i915_debugfs_files {
 	{"i915_dp_test_active", &i915_displayport_test_active_fops}
 };
 
-void intel_display_crc_init(struct drm_i915_private *dev_priv)
-{
-	enum pipe pipe;
-
-	for_each_pipe(dev_priv, pipe) {
-		struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[pipe];
-
-		pipe_crc->opened = false;
-		spin_lock_init(&pipe_crc->lock);
-		init_waitqueue_head(&pipe_crc->wq);
-	}
-}
-
 int i915_debugfs_register(struct drm_i915_private *dev_priv)
 {
 	struct drm_minor *minor = dev_priv->drm.primary;
@@ -5367,11 +4496,9 @@ int i915_debugfs_register(struct drm_i915_private *dev_priv)
 	if (ret)
 		return ret;
 
-	for (i = 0; i < ARRAY_SIZE(i915_pipe_crc_data); i++) {
-		ret = i915_pipe_crc_create(minor->debugfs_root, minor, i);
-		if (ret)
-			return ret;
-	}
+	ret = intel_pipe_crc_create(minor);
+	if (ret)
+		return ret;
 
 	for (i = 0; i < ARRAY_SIZE(i915_debugfs_files); i++) {
 		ret = i915_debugfs_create(minor->debugfs_root, minor,
@@ -5397,12 +4524,7 @@ void i915_debugfs_unregister(struct drm_i915_private *dev_priv)
 	drm_debugfs_remove_files((struct drm_info_list *)&i915_forcewake_fops,
 				 1, minor);
 
-	for (i = 0; i < ARRAY_SIZE(i915_pipe_crc_data); i++) {
-		struct drm_info_list *info_list =
-			(struct drm_info_list *)&i915_pipe_crc_data[i];
-
-		drm_debugfs_remove_files(info_list, 1, minor);
-	}
+	intel_pipe_crc_cleanup(minor);
 
 	for (i = 0; i < ARRAY_SIZE(i915_debugfs_files); i++) {
 		struct drm_info_list *info_list =
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index f48e79ae2ac6..737261b09110 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1841,4 +1841,9 @@ int intel_color_check(struct drm_crtc *crtc, struct drm_crtc_state *state);
 void intel_color_set_csc(struct drm_crtc_state *crtc_state);
 void intel_color_load_luts(struct drm_crtc_state *crtc_state);
 
+/* intel_pipe_crc.c */
+int intel_pipe_crc_create(struct drm_minor *minor);
+void intel_pipe_crc_cleanup(struct drm_minor *minor);
+extern const struct file_operations i915_display_crc_ctl_fops;
+
 #endif /* __INTEL_DRV_H__ */
diff --git a/drivers/gpu/drm/i915/intel_pipe_crc.c b/drivers/gpu/drm/i915/intel_pipe_crc.c
new file mode 100644
index 000000000000..6c38d4fdcaef
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_pipe_crc.c
@@ -0,0 +1,943 @@
+/*
+ * Copyright © 2013 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Author: Damien Lespiau <damien.lespiau@intel.com>
+ *
+ */
+
+#include <linux/seq_file.h>
+#include <linux/circ_buf.h>
+#include <linux/ctype.h>
+#include <linux/debugfs.h>
+#include "intel_drv.h"
+
+struct pipe_crc_info {
+	const char *name;
+	struct drm_i915_private *dev_priv;
+	enum pipe pipe;
+};
+
+/* As the drm_debugfs_init() routines are called before dev->dev_private is
+ * allocated we need to hook into the minor for release.
+ */
+static int drm_add_fake_info_node(struct drm_minor *minor,
+				  struct dentry *ent, const void *key)
+{
+	struct drm_info_node *node;
+
+	node = kmalloc(sizeof(*node), GFP_KERNEL);
+	if (node == NULL) {
+		debugfs_remove(ent);
+		return -ENOMEM;
+	}
+
+	node->minor = minor;
+	node->dent = ent;
+	node->info_ent = (void *) key;
+
+	mutex_lock(&minor->debugfs_lock);
+	list_add(&node->list, &minor->debugfs_list);
+	mutex_unlock(&minor->debugfs_lock);
+
+	return 0;
+}
+
+static int i915_pipe_crc_open(struct inode *inode, struct file *filep)
+{
+	struct pipe_crc_info *info = inode->i_private;
+	struct drm_i915_private *dev_priv = info->dev_priv;
+	struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[info->pipe];
+
+	if (info->pipe >= INTEL_INFO(dev_priv)->num_pipes)
+		return -ENODEV;
+
+	spin_lock_irq(&pipe_crc->lock);
+
+	if (pipe_crc->opened) {
+		spin_unlock_irq(&pipe_crc->lock);
+		return -EBUSY; /* already open */
+	}
+
+	pipe_crc->opened = true;
+	filep->private_data = inode->i_private;
+
+	spin_unlock_irq(&pipe_crc->lock);
+
+	return 0;
+}
+
+static int i915_pipe_crc_release(struct inode *inode, struct file *filep)
+{
+	struct pipe_crc_info *info = inode->i_private;
+	struct drm_i915_private *dev_priv = info->dev_priv;
+	struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[info->pipe];
+
+	spin_lock_irq(&pipe_crc->lock);
+	pipe_crc->opened = false;
+	spin_unlock_irq(&pipe_crc->lock);
+
+	return 0;
+}
+
+/* (6 fields, 8 chars each, space separated (5) + '\n') */
+#define PIPE_CRC_LINE_LEN	(6 * 8 + 5 + 1)
+/* account for \'0' */
+#define PIPE_CRC_BUFFER_LEN	(PIPE_CRC_LINE_LEN + 1)
+
+static int pipe_crc_data_count(struct intel_pipe_crc *pipe_crc)
+{
+	assert_spin_locked(&pipe_crc->lock);
+	return CIRC_CNT(pipe_crc->head, pipe_crc->tail,
+			INTEL_PIPE_CRC_ENTRIES_NR);
+}
+
+static ssize_t
+i915_pipe_crc_read(struct file *filep, char __user *user_buf, size_t count,
+		   loff_t *pos)
+{
+	struct pipe_crc_info *info = filep->private_data;
+	struct drm_i915_private *dev_priv = info->dev_priv;
+	struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[info->pipe];
+	char buf[PIPE_CRC_BUFFER_LEN];
+	int n_entries;
+	ssize_t bytes_read;
+
+	/*
+	 * Don't allow user space to provide buffers not big enough to hold
+	 * a line of data.
+	 */
+	if (count < PIPE_CRC_LINE_LEN)
+		return -EINVAL;
+
+	if (pipe_crc->source == INTEL_PIPE_CRC_SOURCE_NONE)
+		return 0;
+
+	/* nothing to read */
+	spin_lock_irq(&pipe_crc->lock);
+	while (pipe_crc_data_count(pipe_crc) == 0) {
+		int ret;
+
+		if (filep->f_flags & O_NONBLOCK) {
+			spin_unlock_irq(&pipe_crc->lock);
+			return -EAGAIN;
+		}
+
+		ret = wait_event_interruptible_lock_irq(pipe_crc->wq,
+				pipe_crc_data_count(pipe_crc), pipe_crc->lock);
+		if (ret) {
+			spin_unlock_irq(&pipe_crc->lock);
+			return ret;
+		}
+	}
+
+	/* We now have one or more entries to read */
+	n_entries = count / PIPE_CRC_LINE_LEN;
+
+	bytes_read = 0;
+	while (n_entries > 0) {
+		struct intel_pipe_crc_entry *entry =
+			&pipe_crc->entries[pipe_crc->tail];
+
+		if (CIRC_CNT(pipe_crc->head, pipe_crc->tail,
+			     INTEL_PIPE_CRC_ENTRIES_NR) < 1)
+			break;
+
+		BUILD_BUG_ON_NOT_POWER_OF_2(INTEL_PIPE_CRC_ENTRIES_NR);
+		pipe_crc->tail = (pipe_crc->tail + 1) &
+				 (INTEL_PIPE_CRC_ENTRIES_NR - 1);
+
+		bytes_read += snprintf(buf, PIPE_CRC_BUFFER_LEN,
+				       "%8u %8x %8x %8x %8x %8x\n",
+				       entry->frame, entry->crc[0],
+				       entry->crc[1], entry->crc[2],
+				       entry->crc[3], entry->crc[4]);
+
+		spin_unlock_irq(&pipe_crc->lock);
+
+		if (copy_to_user(user_buf, buf, PIPE_CRC_LINE_LEN))
+			return -EFAULT;
+
+		user_buf += PIPE_CRC_LINE_LEN;
+		n_entries--;
+
+		spin_lock_irq(&pipe_crc->lock);
+	}
+
+	spin_unlock_irq(&pipe_crc->lock);
+
+	return bytes_read;
+}
+
+static const struct file_operations i915_pipe_crc_fops = {
+	.owner = THIS_MODULE,
+	.open = i915_pipe_crc_open,
+	.read = i915_pipe_crc_read,
+	.release = i915_pipe_crc_release,
+};
+
+static struct pipe_crc_info i915_pipe_crc_data[I915_MAX_PIPES] = {
+	{
+		.name = "i915_pipe_A_crc",
+		.pipe = PIPE_A,
+	},
+	{
+		.name = "i915_pipe_B_crc",
+		.pipe = PIPE_B,
+	},
+	{
+		.name = "i915_pipe_C_crc",
+		.pipe = PIPE_C,
+	},
+};
+
+static int i915_pipe_crc_create(struct dentry *root, struct drm_minor *minor,
+				enum pipe pipe)
+{
+	struct drm_i915_private *dev_priv = to_i915(minor->dev);
+	struct dentry *ent;
+	struct pipe_crc_info *info = &i915_pipe_crc_data[pipe];
+
+	info->dev_priv = dev_priv;
+	ent = debugfs_create_file(info->name, S_IRUGO, root, info,
+				  &i915_pipe_crc_fops);
+	if (!ent)
+		return -ENOMEM;
+
+	return drm_add_fake_info_node(minor, ent, info);
+}
+
+static const char * const pipe_crc_sources[] = {
+	"none",
+	"plane1",
+	"plane2",
+	"pf",
+	"pipe",
+	"TV",
+	"DP-B",
+	"DP-C",
+	"DP-D",
+	"auto",
+};
+
+static const char *pipe_crc_source_name(enum intel_pipe_crc_source source)
+{
+	BUILD_BUG_ON(ARRAY_SIZE(pipe_crc_sources) != INTEL_PIPE_CRC_SOURCE_MAX);
+	return pipe_crc_sources[source];
+}
+
+static int display_crc_ctl_show(struct seq_file *m, void *data)
+{
+	struct drm_i915_private *dev_priv = m->private;
+	int i;
+
+	for (i = 0; i < I915_MAX_PIPES; i++)
+		seq_printf(m, "%c %s\n", pipe_name(i),
+			   pipe_crc_source_name(dev_priv->pipe_crc[i].source));
+
+	return 0;
+}
+
+static int display_crc_ctl_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, display_crc_ctl_show, inode->i_private);
+}
+
+static int i8xx_pipe_crc_ctl_reg(enum intel_pipe_crc_source *source,
+				 uint32_t *val)
+{
+	if (*source == INTEL_PIPE_CRC_SOURCE_AUTO)
+		*source = INTEL_PIPE_CRC_SOURCE_PIPE;
+
+	switch (*source) {
+	case INTEL_PIPE_CRC_SOURCE_PIPE:
+		*val = PIPE_CRC_ENABLE | PIPE_CRC_INCLUDE_BORDER_I8XX;
+		break;
+	case INTEL_PIPE_CRC_SOURCE_NONE:
+		*val = 0;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int i9xx_pipe_crc_auto_source(struct drm_i915_private *dev_priv,
+				     enum pipe pipe,
+				     enum intel_pipe_crc_source *source)
+{
+	struct drm_device *dev = &dev_priv->drm;
+	struct intel_encoder *encoder;
+	struct intel_crtc *crtc;
+	struct intel_digital_port *dig_port;
+	int ret = 0;
+
+	*source = INTEL_PIPE_CRC_SOURCE_PIPE;
+
+	drm_modeset_lock_all(dev);
+	for_each_intel_encoder(dev, encoder) {
+		if (!encoder->base.crtc)
+			continue;
+
+		crtc = to_intel_crtc(encoder->base.crtc);
+
+		if (crtc->pipe != pipe)
+			continue;
+
+		switch (encoder->type) {
+		case INTEL_OUTPUT_TVOUT:
+			*source = INTEL_PIPE_CRC_SOURCE_TV;
+			break;
+		case INTEL_OUTPUT_DP:
+		case INTEL_OUTPUT_EDP:
+			dig_port = enc_to_dig_port(&encoder->base);
+			switch (dig_port->port) {
+			case PORT_B:
+				*source = INTEL_PIPE_CRC_SOURCE_DP_B;
+				break;
+			case PORT_C:
+				*source = INTEL_PIPE_CRC_SOURCE_DP_C;
+				break;
+			case PORT_D:
+				*source = INTEL_PIPE_CRC_SOURCE_DP_D;
+				break;
+			default:
+				WARN(1, "nonexisting DP port %c\n",
+				     port_name(dig_port->port));
+				break;
+			}
+			break;
+		default:
+			break;
+		}
+	}
+	drm_modeset_unlock_all(dev);
+
+	return ret;
+}
+
+static int vlv_pipe_crc_ctl_reg(struct drm_i915_private *dev_priv,
+				enum pipe pipe,
+				enum intel_pipe_crc_source *source,
+				uint32_t *val)
+{
+	bool need_stable_symbols = false;
+
+	if (*source == INTEL_PIPE_CRC_SOURCE_AUTO) {
+		int ret = i9xx_pipe_crc_auto_source(dev_priv, pipe, source);
+		if (ret)
+			return ret;
+	}
+
+	switch (*source) {
+	case INTEL_PIPE_CRC_SOURCE_PIPE:
+		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_PIPE_VLV;
+		break;
+	case INTEL_PIPE_CRC_SOURCE_DP_B:
+		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_DP_B_VLV;
+		need_stable_symbols = true;
+		break;
+	case INTEL_PIPE_CRC_SOURCE_DP_C:
+		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_DP_C_VLV;
+		need_stable_symbols = true;
+		break;
+	case INTEL_PIPE_CRC_SOURCE_DP_D:
+		if (!IS_CHERRYVIEW(dev_priv))
+			return -EINVAL;
+		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_DP_D_VLV;
+		need_stable_symbols = true;
+		break;
+	case INTEL_PIPE_CRC_SOURCE_NONE:
+		*val = 0;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/*
+	 * When the pipe CRC tap point is after the transcoders we need
+	 * to tweak symbol-level features to produce a deterministic series of
+	 * symbols for a given frame. We need to reset those features only once
+	 * a frame (instead of every nth symbol):
+	 *   - DC-balance: used to ensure a better clock recovery from the data
+	 *     link (SDVO)
+	 *   - DisplayPort scrambling: used for EMI reduction
+	 */
+	if (need_stable_symbols) {
+		uint32_t tmp = I915_READ(PORT_DFT2_G4X);
+
+		tmp |= DC_BALANCE_RESET_VLV;
+		switch (pipe) {
+		case PIPE_A:
+			tmp |= PIPE_A_SCRAMBLE_RESET;
+			break;
+		case PIPE_B:
+			tmp |= PIPE_B_SCRAMBLE_RESET;
+			break;
+		case PIPE_C:
+			tmp |= PIPE_C_SCRAMBLE_RESET;
+			break;
+		default:
+			return -EINVAL;
+		}
+		I915_WRITE(PORT_DFT2_G4X, tmp);
+	}
+
+	return 0;
+}
+
+static int i9xx_pipe_crc_ctl_reg(struct drm_i915_private *dev_priv,
+				 enum pipe pipe,
+				 enum intel_pipe_crc_source *source,
+				 uint32_t *val)
+{
+	bool need_stable_symbols = false;
+
+	if (*source == INTEL_PIPE_CRC_SOURCE_AUTO) {
+		int ret = i9xx_pipe_crc_auto_source(dev_priv, pipe, source);
+		if (ret)
+			return ret;
+	}
+
+	switch (*source) {
+	case INTEL_PIPE_CRC_SOURCE_PIPE:
+		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_PIPE_I9XX;
+		break;
+	case INTEL_PIPE_CRC_SOURCE_TV:
+		if (!SUPPORTS_TV(dev_priv))
+			return -EINVAL;
+		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_TV_PRE;
+		break;
+	case INTEL_PIPE_CRC_SOURCE_DP_B:
+		if (!IS_G4X(dev_priv))
+			return -EINVAL;
+		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_DP_B_G4X;
+		need_stable_symbols = true;
+		break;
+	case INTEL_PIPE_CRC_SOURCE_DP_C:
+		if (!IS_G4X(dev_priv))
+			return -EINVAL;
+		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_DP_C_G4X;
+		need_stable_symbols = true;
+		break;
+	case INTEL_PIPE_CRC_SOURCE_DP_D:
+		if (!IS_G4X(dev_priv))
+			return -EINVAL;
+		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_DP_D_G4X;
+		need_stable_symbols = true;
+		break;
+	case INTEL_PIPE_CRC_SOURCE_NONE:
+		*val = 0;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/*
+	 * When the pipe CRC tap point is after the transcoders we need
+	 * to tweak symbol-level features to produce a deterministic series of
+	 * symbols for a given frame. We need to reset those features only once
+	 * a frame (instead of every nth symbol):
+	 *   - DC-balance: used to ensure a better clock recovery from the data
+	 *     link (SDVO)
+	 *   - DisplayPort scrambling: used for EMI reduction
+	 */
+	if (need_stable_symbols) {
+		uint32_t tmp = I915_READ(PORT_DFT2_G4X);
+
+		WARN_ON(!IS_G4X(dev_priv));
+
+		I915_WRITE(PORT_DFT_I9XX,
+			   I915_READ(PORT_DFT_I9XX) | DC_BALANCE_RESET);
+
+		if (pipe == PIPE_A)
+			tmp |= PIPE_A_SCRAMBLE_RESET;
+		else
+			tmp |= PIPE_B_SCRAMBLE_RESET;
+
+		I915_WRITE(PORT_DFT2_G4X, tmp);
+	}
+
+	return 0;
+}
+
+static void vlv_undo_pipe_scramble_reset(struct drm_i915_private *dev_priv,
+					 enum pipe pipe)
+{
+	uint32_t tmp = I915_READ(PORT_DFT2_G4X);
+
+	switch (pipe) {
+	case PIPE_A:
+		tmp &= ~PIPE_A_SCRAMBLE_RESET;
+		break;
+	case PIPE_B:
+		tmp &= ~PIPE_B_SCRAMBLE_RESET;
+		break;
+	case PIPE_C:
+		tmp &= ~PIPE_C_SCRAMBLE_RESET;
+		break;
+	default:
+		return;
+	}
+	if (!(tmp & PIPE_SCRAMBLE_RESET_MASK))
+		tmp &= ~DC_BALANCE_RESET_VLV;
+	I915_WRITE(PORT_DFT2_G4X, tmp);
+
+}
+
+static void g4x_undo_pipe_scramble_reset(struct drm_i915_private *dev_priv,
+					 enum pipe pipe)
+{
+	uint32_t tmp = I915_READ(PORT_DFT2_G4X);
+
+	if (pipe == PIPE_A)
+		tmp &= ~PIPE_A_SCRAMBLE_RESET;
+	else
+		tmp &= ~PIPE_B_SCRAMBLE_RESET;
+	I915_WRITE(PORT_DFT2_G4X, tmp);
+
+	if (!(tmp & PIPE_SCRAMBLE_RESET_MASK)) {
+		I915_WRITE(PORT_DFT_I9XX,
+			   I915_READ(PORT_DFT_I9XX) & ~DC_BALANCE_RESET);
+	}
+}
+
+static int ilk_pipe_crc_ctl_reg(enum intel_pipe_crc_source *source,
+				uint32_t *val)
+{
+	if (*source == INTEL_PIPE_CRC_SOURCE_AUTO)
+		*source = INTEL_PIPE_CRC_SOURCE_PIPE;
+
+	switch (*source) {
+	case INTEL_PIPE_CRC_SOURCE_PLANE1:
+		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_PRIMARY_ILK;
+		break;
+	case INTEL_PIPE_CRC_SOURCE_PLANE2:
+		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_SPRITE_ILK;
+		break;
+	case INTEL_PIPE_CRC_SOURCE_PIPE:
+		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_PIPE_ILK;
+		break;
+	case INTEL_PIPE_CRC_SOURCE_NONE:
+		*val = 0;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void hsw_trans_edp_pipe_A_crc_wa(struct drm_i915_private *dev_priv,
+					bool enable)
+{
+	struct drm_device *dev = &dev_priv->drm;
+	struct intel_crtc *crtc =
+		to_intel_crtc(dev_priv->pipe_to_crtc_mapping[PIPE_A]);
+	struct intel_crtc_state *pipe_config;
+	struct drm_atomic_state *state;
+	int ret = 0;
+
+	drm_modeset_lock_all(dev);
+	state = drm_atomic_state_alloc(dev);
+	if (!state) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	state->acquire_ctx = drm_modeset_legacy_acquire_ctx(&crtc->base);
+	pipe_config = intel_atomic_get_crtc_state(state, crtc);
+	if (IS_ERR(pipe_config)) {
+		ret = PTR_ERR(pipe_config);
+		goto out;
+	}
+
+	pipe_config->pch_pfit.force_thru = enable;
+	if (pipe_config->cpu_transcoder == TRANSCODER_EDP &&
+	    pipe_config->pch_pfit.enabled != enable)
+		pipe_config->base.connectors_changed = true;
+
+	ret = drm_atomic_commit(state);
+out:
+	drm_modeset_unlock_all(dev);
+	WARN(ret, "Toggling workaround to %i returns %i\n", enable, ret);
+	if (ret)
+		drm_atomic_state_free(state);
+}
+
+static int ivb_pipe_crc_ctl_reg(struct drm_i915_private *dev_priv,
+				enum pipe pipe,
+				enum intel_pipe_crc_source *source,
+				uint32_t *val)
+{
+	if (*source == INTEL_PIPE_CRC_SOURCE_AUTO)
+		*source = INTEL_PIPE_CRC_SOURCE_PF;
+
+	switch (*source) {
+	case INTEL_PIPE_CRC_SOURCE_PLANE1:
+		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_PRIMARY_IVB;
+		break;
+	case INTEL_PIPE_CRC_SOURCE_PLANE2:
+		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_SPRITE_IVB;
+		break;
+	case INTEL_PIPE_CRC_SOURCE_PF:
+		if (IS_HASWELL(dev_priv) && pipe == PIPE_A)
+			hsw_trans_edp_pipe_A_crc_wa(dev_priv, true);
+
+		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_PF_IVB;
+		break;
+	case INTEL_PIPE_CRC_SOURCE_NONE:
+		*val = 0;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int pipe_crc_set_source(struct drm_i915_private *dev_priv,
+			       enum pipe pipe,
+			       enum intel_pipe_crc_source source)
+{
+	struct drm_device *dev = &dev_priv->drm;
+	struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[pipe];
+	struct intel_crtc *crtc =
+			to_intel_crtc(intel_get_crtc_for_pipe(dev, pipe));
+	enum intel_display_power_domain power_domain;
+	u32 val = 0; /* shut up gcc */
+	int ret;
+
+	if (pipe_crc->source == source)
+		return 0;
+
+	/* forbid changing the source without going back to 'none' */
+	if (pipe_crc->source && source)
+		return -EINVAL;
+
+	power_domain = POWER_DOMAIN_PIPE(pipe);
+	if (!intel_display_power_get_if_enabled(dev_priv, power_domain)) {
+		DRM_DEBUG_KMS("Trying to capture CRC while pipe is off\n");
+		return -EIO;
+	}
+
+	if (IS_GEN2(dev_priv))
+		ret = i8xx_pipe_crc_ctl_reg(&source, &val);
+	else if (INTEL_GEN(dev_priv) < 5)
+		ret = i9xx_pipe_crc_ctl_reg(dev_priv, pipe, &source, &val);
+	else if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
+		ret = vlv_pipe_crc_ctl_reg(dev_priv, pipe, &source, &val);
+	else if (IS_GEN5(dev_priv) || IS_GEN6(dev_priv))
+		ret = ilk_pipe_crc_ctl_reg(&source, &val);
+	else
+		ret = ivb_pipe_crc_ctl_reg(dev_priv, pipe, &source, &val);
+
+	if (ret != 0)
+		goto out;
+
+	/* none -> real source transition */
+	if (source) {
+		struct intel_pipe_crc_entry *entries;
+
+		DRM_DEBUG_DRIVER("collecting CRCs for pipe %c, %s\n",
+				 pipe_name(pipe), pipe_crc_source_name(source));
+
+		entries = kcalloc(INTEL_PIPE_CRC_ENTRIES_NR,
+				  sizeof(pipe_crc->entries[0]),
+				  GFP_KERNEL);
+		if (!entries) {
+			ret = -ENOMEM;
+			goto out;
+		}
+
+		/*
+		 * When IPS gets enabled, the pipe CRC changes. Since IPS gets
+		 * enabled and disabled dynamically based on package C states,
+		 * user space can't make reliable use of the CRCs, so let's just
+		 * completely disable it.
+		 */
+		hsw_disable_ips(crtc);
+
+		spin_lock_irq(&pipe_crc->lock);
+		kfree(pipe_crc->entries);
+		pipe_crc->entries = entries;
+		pipe_crc->head = 0;
+		pipe_crc->tail = 0;
+		spin_unlock_irq(&pipe_crc->lock);
+	}
+
+	pipe_crc->source = source;
+
+	I915_WRITE(PIPE_CRC_CTL(pipe), val);
+	POSTING_READ(PIPE_CRC_CTL(pipe));
+
+	/* real source -> none transition */
+	if (source == INTEL_PIPE_CRC_SOURCE_NONE) {
+		struct intel_pipe_crc_entry *entries;
+		struct intel_crtc *crtc =
+			to_intel_crtc(dev_priv->pipe_to_crtc_mapping[pipe]);
+
+		DRM_DEBUG_DRIVER("stopping CRCs for pipe %c\n",
+				 pipe_name(pipe));
+
+		drm_modeset_lock(&crtc->base.mutex, NULL);
+		if (crtc->base.state->active)
+			intel_wait_for_vblank(dev, pipe);
+		drm_modeset_unlock(&crtc->base.mutex);
+
+		spin_lock_irq(&pipe_crc->lock);
+		entries = pipe_crc->entries;
+		pipe_crc->entries = NULL;
+		pipe_crc->head = 0;
+		pipe_crc->tail = 0;
+		spin_unlock_irq(&pipe_crc->lock);
+
+		kfree(entries);
+
+		if (IS_G4X(dev_priv))
+			g4x_undo_pipe_scramble_reset(dev_priv, pipe);
+		else if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
+			vlv_undo_pipe_scramble_reset(dev_priv, pipe);
+		else if (IS_HASWELL(dev_priv) && pipe == PIPE_A)
+			hsw_trans_edp_pipe_A_crc_wa(dev_priv, false);
+
+		hsw_enable_ips(crtc);
+	}
+
+	ret = 0;
+
+out:
+	intel_display_power_put(dev_priv, power_domain);
+
+	return ret;
+}
+
+/*
+ * Parse pipe CRC command strings:
+ *   command: wsp* object wsp+ name wsp+ source wsp*
+ *   object: 'pipe'
+ *   name: (A | B | C)
+ *   source: (none | plane1 | plane2 | pf)
+ *   wsp: (#0x20 | #0x9 | #0xA)+
+ *
+ * eg.:
+ *  "pipe A plane1"  ->  Start CRC computations on plane1 of pipe A
+ *  "pipe A none"    ->  Stop CRC
+ */
+static int display_crc_ctl_tokenize(char *buf, char *words[], int max_words)
+{
+	int n_words = 0;
+
+	while (*buf) {
+		char *end;
+
+		/* skip leading white space */
+		buf = skip_spaces(buf);
+		if (!*buf)
+			break;	/* end of buffer */
+
+		/* find end of word */
+		for (end = buf; *end && !isspace(*end); end++)
+			;
+
+		if (n_words == max_words) {
+			DRM_DEBUG_DRIVER("too many words, allowed <= %d\n",
+					 max_words);
+			return -EINVAL;	/* ran out of words[] before bytes */
+		}
+
+		if (*end)
+			*end++ = '\0';
+		words[n_words++] = buf;
+		buf = end;
+	}
+
+	return n_words;
+}
+
+enum intel_pipe_crc_object {
+	PIPE_CRC_OBJECT_PIPE,
+};
+
+static const char * const pipe_crc_objects[] = {
+	"pipe",
+};
+
+static int
+display_crc_ctl_parse_object(const char *buf, enum intel_pipe_crc_object *o)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(pipe_crc_objects); i++)
+		if (!strcmp(buf, pipe_crc_objects[i])) {
+			*o = i;
+			return 0;
+		}
+
+	return -EINVAL;
+}
+
+static int display_crc_ctl_parse_pipe(const char *buf, enum pipe *pipe)
+{
+	const char name = buf[0];
+
+	if (name < 'A' || name >= pipe_name(I915_MAX_PIPES))
+		return -EINVAL;
+
+	*pipe = name - 'A';
+
+	return 0;
+}
+
+static int
+display_crc_ctl_parse_source(const char *buf, enum intel_pipe_crc_source *s)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(pipe_crc_sources); i++)
+		if (!strcmp(buf, pipe_crc_sources[i])) {
+			*s = i;
+			return 0;
+		}
+
+	return -EINVAL;
+}
+
+static int display_crc_ctl_parse(struct drm_i915_private *dev_priv,
+				 char *buf, size_t len)
+{
+#define N_WORDS 3
+	int n_words;
+	char *words[N_WORDS];
+	enum pipe pipe;
+	enum intel_pipe_crc_object object;
+	enum intel_pipe_crc_source source;
+
+	n_words = display_crc_ctl_tokenize(buf, words, N_WORDS);
+	if (n_words != N_WORDS) {
+		DRM_DEBUG_DRIVER("tokenize failed, a command is %d words\n",
+				 N_WORDS);
+		return -EINVAL;
+	}
+
+	if (display_crc_ctl_parse_object(words[0], &object) < 0) {
+		DRM_DEBUG_DRIVER("unknown object %s\n", words[0]);
+		return -EINVAL;
+	}
+
+	if (display_crc_ctl_parse_pipe(words[1], &pipe) < 0) {
+		DRM_DEBUG_DRIVER("unknown pipe %s\n", words[1]);
+		return -EINVAL;
+	}
+
+	if (display_crc_ctl_parse_source(words[2], &source) < 0) {
+		DRM_DEBUG_DRIVER("unknown source %s\n", words[2]);
+		return -EINVAL;
+	}
+
+	return pipe_crc_set_source(dev_priv, pipe, source);
+}
+
+static ssize_t display_crc_ctl_write(struct file *file, const char __user *ubuf,
+				     size_t len, loff_t *offp)
+{
+	struct seq_file *m = file->private_data;
+	struct drm_i915_private *dev_priv = m->private;
+	char *tmpbuf;
+	int ret;
+
+	if (len == 0)
+		return 0;
+
+	if (len > PAGE_SIZE - 1) {
+		DRM_DEBUG_DRIVER("expected <%lu bytes into pipe crc control\n",
+				 PAGE_SIZE);
+		return -E2BIG;
+	}
+
+	tmpbuf = kmalloc(len + 1, GFP_KERNEL);
+	if (!tmpbuf)
+		return -ENOMEM;
+
+	if (copy_from_user(tmpbuf, ubuf, len)) {
+		ret = -EFAULT;
+		goto out;
+	}
+	tmpbuf[len] = '\0';
+
+	ret = display_crc_ctl_parse(dev_priv, tmpbuf, len);
+
+out:
+	kfree(tmpbuf);
+	if (ret < 0)
+		return ret;
+
+	*offp += len;
+	return len;
+}
+
+const struct file_operations i915_display_crc_ctl_fops = {
+	.owner = THIS_MODULE,
+	.open = display_crc_ctl_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+	.write = display_crc_ctl_write
+};
+
+void intel_display_crc_init(struct drm_i915_private *dev_priv)
+{
+	enum pipe pipe;
+
+	for_each_pipe(dev_priv, pipe) {
+		struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[pipe];
+
+		pipe_crc->opened = false;
+		spin_lock_init(&pipe_crc->lock);
+		init_waitqueue_head(&pipe_crc->wq);
+	}
+}
+
+int intel_pipe_crc_create(struct drm_minor *minor)
+{
+	int ret, i;
+
+	for (i = 0; i < ARRAY_SIZE(i915_pipe_crc_data); i++) {
+		ret = i915_pipe_crc_create(minor->debugfs_root, minor, i);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+void intel_pipe_crc_cleanup(struct drm_minor *minor)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(i915_pipe_crc_data); i++) {
+		struct drm_info_list *info_list =
+			(struct drm_info_list *)&i915_pipe_crc_data[i];
+
+		drm_debugfs_remove_files(info_list, 1, minor);
+	}
+}
-- 
2.7.4

[PATCH v11 2/4] drm: Add API for capturing frame CRCs

[Tomeu Vizoso]

Adds files and directories to debugfs for controlling and reading frame
CRCs, per CRTC:

dri/0/crtc-0/crc
dri/0/crtc-0/crc/control
dri/0/crtc-0/crc/data

Drivers can implement the set_crc_source callback() in drm_crtc_funcs to
start and stop generating frame CRCs and can add entries to the output
by calling drm_crtc_add_crc_entry.

v2:
    - Lots of good fixes suggested by Thierry.
    - Added documentation.
    - Changed the debugfs layout.
    - Moved to allocate the entries circular queue once when frame
      generation gets enabled for the first time.
v3:
    - Use the control file just to select the source, and start and stop
      capture when the data file is opened and closed, respectively.
    - Make variable the number of CRC values per entry, per source.
    - Allocate entries queue each time we start capturing as now there
      isn't a fixed number of CRC values per entry.
    - Store the frame counter in the data file as a 8-digit hex number.
    - For sources that cannot provide useful frame numbers, place
      XXXXXXXX in the frame field.

v4:
    - Build only if CONFIG_DEBUG_FS is enabled.
    - Use memdup_user_nul.
    - Consolidate calculation of the size of an entry in a helper.
    - Add 0x prefix to hex numbers in the data file.
    - Remove unnecessary snprintf and strlen usage in read callback.

v5:
    - Made the crcs array in drm_crtc_crc_entry fixed-size
    - Lots of other smaller improvements suggested by Emil Velikov

v7:
    - Move definition of drm_debugfs_crtc_crc_add to drm_internal.h

v8:
    - Call debugfs_remove_recursive when we fail to create the minor
      device

v9:
    - Register the debugfs directory for a crtc from
      drm_crtc_register_all()

v10:
    - Don't let debugfs failures interrupt CRTC registration (Emil
      Velikov)

v11:
    - Remove extra brace that broke compilation. Sorry!

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
---

 Documentation/gpu/drm-uapi.rst    |   6 +
 drivers/gpu/drm/Makefile          |   3 +-
 drivers/gpu/drm/drm_crtc.c        |  34 +++-
 drivers/gpu/drm/drm_debugfs.c     |  34 +++-
 drivers/gpu/drm/drm_debugfs_crc.c | 351 ++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/drm_internal.h    |  16 ++
 include/drm/drm_crtc.h            |  41 +++++
 include/drm/drm_debugfs_crc.h     |  73 ++++++++
 8 files changed, 555 insertions(+), 3 deletions(-)
 create mode 100644 drivers/gpu/drm/drm_debugfs_crc.c
 create mode 100644 include/drm/drm_debugfs_crc.h

diff --git a/Documentation/gpu/drm-uapi.rst b/Documentation/gpu/drm-uapi.rst
index 1ba301cebe16..de3ac9f90f8f 100644
--- a/Documentation/gpu/drm-uapi.rst
+++ b/Documentation/gpu/drm-uapi.rst
@@ -216,3 +216,9 @@ interfaces. Especially since all hardware-acceleration interfaces to
 userspace are driver specific for efficiency and other reasons these
 interfaces can be rather substantial. Hence every driver has its own
 chapter.
+
+Testing and validation
+======================
+
+.. kernel-doc:: drivers/gpu/drm/drm_debugfs_crc.c
+   :doc: CRC ABI
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 25c720454017..74579d2e796e 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -9,7 +9,7 @@ drm-y       :=	drm_auth.o drm_bufs.o drm_cache.o \
 		drm_scatter.o drm_pci.o \
 		drm_platform.o drm_sysfs.o drm_hashtab.o drm_mm.o \
 		drm_crtc.o drm_fourcc.o drm_modes.o drm_edid.o \
-		drm_info.o drm_debugfs.o drm_encoder_slave.o \
+		drm_info.o drm_encoder_slave.o \
 		drm_trace_points.o drm_global.o drm_prime.o \
 		drm_rect.o drm_vma_manager.o drm_flip_work.o \
 		drm_modeset_lock.o drm_atomic.o drm_bridge.o \
@@ -23,6 +23,7 @@ drm-$(CONFIG_PCI) += ati_pcigart.o
 drm-$(CONFIG_DRM_PANEL) += drm_panel.o
 drm-$(CONFIG_OF) += drm_of.o
 drm-$(CONFIG_AGP) += drm_agpsupport.o
+drm-$(CONFIG_DEBUG_FS) += drm_debugfs.o drm_debugfs_crc.o
 
 drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \
 		drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o \
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 2d7bedf28647..60403bf7a4ff 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -40,7 +40,7 @@
 #include <drm/drm_modeset_lock.h>
 #include <drm/drm_atomic.h>
 #include <drm/drm_auth.h>
-#include <drm/drm_framebuffer.h>
+#include <drm/drm_debugfs_crc.h>
 
 #include "drm_crtc_internal.h"
 #include "drm_internal.h"
@@ -122,6 +122,10 @@ static int drm_crtc_register_all(struct drm_device *dev)
 	int ret = 0;
 
 	drm_for_each_crtc(crtc, dev) {
+		if (drm_debugfs_crtc_add(crtc))
+			DRM_ERROR("Failed to initialize debugfs entry for CRTC '%s'.\n",
+				  crtc->name);
+
 		if (crtc->funcs->late_register)
 			ret = crtc->funcs->late_register(crtc);
 		if (ret)
@@ -138,9 +142,29 @@ static void drm_crtc_unregister_all(struct drm_device *dev)
 	drm_for_each_crtc(crtc, dev) {
 		if (crtc->funcs->early_unregister)
 			crtc->funcs->early_unregister(crtc);
+		drm_debugfs_crtc_remove(crtc);
 	}
 }
 
+static int drm_crtc_crc_init(struct drm_crtc *crtc)
+{
+#ifdef CONFIG_DEBUG_FS
+	spin_lock_init(&crtc->crc.lock);
+	init_waitqueue_head(&crtc->crc.wq);
+	crtc->crc.source = kstrdup("auto", GFP_KERNEL);
+	if (!crtc->crc.source)
+		return -ENOMEM;
+#endif
+	return 0;
+}
+
+static void drm_crtc_crc_fini(struct drm_crtc *crtc)
+{
+#ifdef CONFIG_DEBUG_FS
+	kfree(crtc->crc.source);
+#endif
+}
+
 /**
  * drm_crtc_init_with_planes - Initialise a new CRTC object with
  *    specified primary and cursor planes.
@@ -210,6 +234,12 @@ int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc,
 	if (cursor)
 		cursor->possible_crtcs = 1 << drm_crtc_index(crtc);
 
+	ret = drm_crtc_crc_init(crtc);
+	if (ret) {
+		drm_mode_object_unregister(dev, &crtc->base);
+		return ret;
+	}
+
 	if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
 		drm_object_attach_property(&crtc->base, config->prop_active, 0);
 		drm_object_attach_property(&crtc->base, config->prop_mode_id, 0);
@@ -236,6 +266,8 @@ void drm_crtc_cleanup(struct drm_crtc *crtc)
 	 * the indices on the drm_crtc after us in the crtc_list.
 	 */
 
+	drm_crtc_crc_fini(crtc);
+
 	kfree(crtc->gamma_store);
 	crtc->gamma_store = NULL;
 
diff --git a/drivers/gpu/drm/drm_debugfs.c b/drivers/gpu/drm/drm_debugfs.c
index 1205790ed960..800055c39cdb 100644
--- a/drivers/gpu/drm/drm_debugfs.c
+++ b/drivers/gpu/drm/drm_debugfs.c
@@ -415,5 +415,37 @@ void drm_debugfs_connector_remove(struct drm_connector *connector)
 	connector->debugfs_entry = NULL;
 }
 
-#endif /* CONFIG_DEBUG_FS */
+int drm_debugfs_crtc_add(struct drm_crtc *crtc)
+{
+	struct drm_minor *minor = crtc->dev->primary;
+	struct dentry *root;
+	char *name;
+
+	name = kasprintf(GFP_KERNEL, "crtc-%d", crtc->index);
+	if (!name)
+		return -ENOMEM;
+
+	root = debugfs_create_dir(name, minor->debugfs_root);
+	kfree(name);
+	if (!root)
+		return -ENOMEM;
+
+	crtc->debugfs_entry = root;
+
+	if (drm_debugfs_crtc_crc_add(crtc))
+		goto error;
 
+	return 0;
+
+error:
+	drm_debugfs_crtc_remove(crtc);
+	return -ENOMEM;
+}
+
+void drm_debugfs_crtc_remove(struct drm_crtc *crtc)
+{
+	debugfs_remove_recursive(crtc->debugfs_entry);
+	crtc->debugfs_entry = NULL;
+}
+
+#endif /* CONFIG_DEBUG_FS */
diff --git a/drivers/gpu/drm/drm_debugfs_crc.c b/drivers/gpu/drm/drm_debugfs_crc.c
new file mode 100644
index 000000000000..4129405d17c0
--- /dev/null
+++ b/drivers/gpu/drm/drm_debugfs_crc.c
@@ -0,0 +1,351 @@
+/*
+ * Copyright © 2008 Intel Corporation
+ * Copyright © 2016 Collabora Ltd
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Based on code from the i915 driver.
+ * Original author: Damien Lespiau <damien.lespiau@intel.com>
+ *
+ */
+
+#include <linux/circ_buf.h>
+#include <linux/ctype.h>
+#include <linux/debugfs.h>
+#include <drm/drmP.h>
+
+/**
+ * DOC: CRC ABI
+ *
+ * DRM device drivers can provide to userspace CRC information of each frame as
+ * it reached a given hardware component (a "source").
+ *
+ * Userspace can control generation of CRCs in a given CRTC by writing to the
+ * file dri/0/crtc-N/crc/control in debugfs, with N being the index of the CRTC.
+ * Accepted values are source names (which are driver-specific) and the "auto"
+ * keyword, which will let the driver select a default source of frame CRCs
+ * for this CRTC.
+ *
+ * Once frame CRC generation is enabled, userspace can capture them by reading
+ * the dri/0/crtc-N/crc/data file. Each line in that file contains the frame
+ * number in the first field and then a number of unsigned integer fields
+ * containing the CRC data. Fields are separated by a single space and the number
+ * of CRC fields is source-specific.
+ *
+ * Note that though in some cases the CRC is computed in a specified way and on
+ * the frame contents as supplied by userspace (eDP 1.3), in general the CRC
+ * computation is performed in an unspecified way and on frame contents that have
+ * been already processed in also an unspecified way and thus userspace cannot
+ * rely on being able to generate matching CRC values for the frame contents that
+ * it submits. In this general case, the maximum userspace can do is to compare
+ * the reported CRCs of frames that should have the same contents.
+ */
+
+static int crc_control_show(struct seq_file *m, void *data)
+{
+	struct drm_crtc *crtc = m->private;
+
+	seq_printf(m, "%s\n", crtc->crc.source);
+
+	return 0;
+}
+
+static int crc_control_open(struct inode *inode, struct file *file)
+{
+	struct drm_crtc *crtc = inode->i_private;
+
+	return single_open(file, crc_control_show, crtc);
+}
+
+static ssize_t crc_control_write(struct file *file, const char __user *ubuf,
+				 size_t len, loff_t *offp)
+{
+	struct seq_file *m = file->private_data;
+	struct drm_crtc *crtc = m->private;
+	struct drm_crtc_crc *crc = &crtc->crc;
+	char *source;
+
+	if (len == 0)
+		return 0;
+
+	if (len > PAGE_SIZE - 1) {
+		DRM_DEBUG_KMS("Expected < %lu bytes into crtc crc control\n",
+			      PAGE_SIZE);
+		return -E2BIG;
+	}
+
+	source = memdup_user_nul(ubuf, len);
+	if (IS_ERR(source))
+		return PTR_ERR(source);
+
+	if (source[len] == '\n')
+		source[len] = '\0';
+
+	spin_lock_irq(&crc->lock);
+
+	if (crc->opened) {
+		spin_unlock_irq(&crc->lock);
+		kfree(source);
+		return -EBUSY;
+	}
+
+	kfree(crc->source);
+	crc->source = source;
+
+	spin_unlock_irq(&crc->lock);
+
+	*offp += len;
+	return len;
+}
+
+const struct file_operations drm_crtc_crc_control_fops = {
+	.owner = THIS_MODULE,
+	.open = crc_control_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+	.write = crc_control_write
+};
+
+static int crtc_crc_open(struct inode *inode, struct file *filep)
+{
+	struct drm_crtc *crtc = inode->i_private;
+	struct drm_crtc_crc *crc = &crtc->crc;
+	struct drm_crtc_crc_entry *entries = NULL;
+	size_t values_cnt;
+	int ret;
+
+	if (crc->opened)
+		return -EBUSY;
+
+	ret = crtc->funcs->set_crc_source(crtc, crc->source, &values_cnt);
+	if (ret)
+		return ret;
+
+	if (WARN_ON(values_cnt > DRM_MAX_CRC_NR)) {
+		ret = -EINVAL;
+		goto err_disable;
+	}
+
+	if (WARN_ON(values_cnt == 0)) {
+		ret = -EINVAL;
+		goto err_disable;
+	}
+
+	entries = kcalloc(DRM_CRC_ENTRIES_NR, sizeof(*entries), GFP_KERNEL);
+	if (!entries) {
+		ret = -ENOMEM;
+		goto err_disable;
+	}
+
+	spin_lock_irq(&crc->lock);
+	crc->entries = entries;
+	crc->values_cnt = values_cnt;
+	crc->opened = true;
+	spin_unlock_irq(&crc->lock);
+
+	return 0;
+
+err_disable:
+	crtc->funcs->set_crc_source(crtc, NULL, &values_cnt);
+	return ret;
+}
+
+static int crtc_crc_release(struct inode *inode, struct file *filep)
+{
+	struct drm_crtc *crtc = filep->f_inode->i_private;
+	struct drm_crtc_crc *crc = &crtc->crc;
+	size_t values_cnt;
+
+	spin_lock_irq(&crc->lock);
+	kfree(crc->entries);
+	crc->entries = NULL;
+	crc->head = 0;
+	crc->tail = 0;
+	crc->values_cnt = 0;
+	crc->opened = false;
+	spin_unlock_irq(&crc->lock);
+
+	crtc->funcs->set_crc_source(crtc, NULL, &values_cnt);
+
+	return 0;
+}
+
+static int crtc_crc_data_count(struct drm_crtc_crc *crc)
+{
+	assert_spin_locked(&crc->lock);
+	return CIRC_CNT(crc->head, crc->tail, DRM_CRC_ENTRIES_NR);
+}
+
+/*
+ * 1 frame field of 10 chars plus a number of CRC fields of 10 chars each, space
+ * separated, with a newline at the end and null-terminated.
+ */
+#define LINE_LEN(values_cnt)	(10 + 11 * values_cnt + 1 + 1)
+#define MAX_LINE_LEN		(LINE_LEN(DRM_MAX_CRC_NR))
+
+static ssize_t crtc_crc_read(struct file *filep, char __user *user_buf,
+			     size_t count, loff_t *pos)
+{
+	struct drm_crtc *crtc = filep->f_inode->i_private;
+	struct drm_crtc_crc *crc = &crtc->crc;
+	struct drm_crtc_crc_entry *entry;
+	char buf[MAX_LINE_LEN];
+	int ret, i;
+
+	spin_lock_irq(&crc->lock);
+
+	if (!crc->source) {
+		spin_unlock_irq(&crc->lock);
+		return 0;
+	}
+
+	/* Nothing to read? */
+	while (crtc_crc_data_count(crc) == 0) {
+		if (filep->f_flags & O_NONBLOCK) {
+			spin_unlock_irq(&crc->lock);
+			return -EAGAIN;
+		}
+
+		ret = wait_event_interruptible_lock_irq(crc->wq,
+							crtc_crc_data_count(crc),
+							crc->lock);
+		if (ret) {
+			spin_unlock_irq(&crc->lock);
+			return ret;
+		}
+	}
+
+	/* We know we have an entry to be read */
+	entry = &crc->entries[crc->tail];
+
+	if (count < LINE_LEN(crc->values_cnt)) {
+		spin_unlock_irq(&crc->lock);
+		return -EINVAL;
+	}
+
+	BUILD_BUG_ON_NOT_POWER_OF_2(DRM_CRC_ENTRIES_NR);
+	crc->tail = (crc->tail + 1) & (DRM_CRC_ENTRIES_NR - 1);
+
+	spin_unlock_irq(&crc->lock);
+
+	if (entry->has_frame_counter)
+		sprintf(buf, "0x%08x", entry->frame);
+	else
+		sprintf(buf, "XXXXXXXXXX");
+
+	for (i = 0; i < crc->values_cnt; i++)
+		sprintf(buf + 10 + i * 11, " 0x%08x", entry->crcs[i]);
+	sprintf(buf + 10 + crc->values_cnt * 11, "\n");
+
+	if (copy_to_user(user_buf, buf, LINE_LEN(crc->values_cnt)))
+		return -EFAULT;
+
+	return LINE_LEN(crc->values_cnt);
+}
+
+const struct file_operations drm_crtc_crc_data_fops = {
+	.owner = THIS_MODULE,
+	.open = crtc_crc_open,
+	.read = crtc_crc_read,
+	.release = crtc_crc_release,
+};
+
+/**
+ * drm_debugfs_crtc_crc_add - Add files to debugfs for capture of frame CRCs
+ * @crtc: CRTC to whom the frames will belong
+ *
+ * Adds files to debugfs directory that allows userspace to control the
+ * generation of frame CRCs and to read them.
+ *
+ * Returns:
+ * Zero on success, error code on failure.
+ */
+int drm_debugfs_crtc_crc_add(struct drm_crtc *crtc)
+{
+	struct dentry *crc_ent, *ent;
+
+	if (!crtc->funcs->set_crc_source)
+		return 0;
+
+	crc_ent = debugfs_create_dir("crc", crtc->debugfs_entry);
+	if (!crc_ent)
+		return -ENOMEM;
+
+	ent = debugfs_create_file("control", S_IRUGO, crc_ent, crtc,
+				  &drm_crtc_crc_control_fops);
+	if (!ent)
+		goto error;
+
+	ent = debugfs_create_file("data", S_IRUGO, crc_ent, crtc,
+				  &drm_crtc_crc_data_fops);
+	if (!ent)
+		goto error;
+
+	return 0;
+
+error:
+	debugfs_remove_recursive(crc_ent);
+
+	return -ENOMEM;
+}
+
+/**
+ * drm_crtc_add_crc_entry - Add entry with CRC information for a frame
+ * @crtc: CRTC to which the frame belongs
+ * @has_frame: whether this entry has a frame number to go with
+ * @frame: number of the frame these CRCs are about
+ * @crcs: array of CRC values, with length matching #drm_crtc_crc.values_cnt
+ *
+ * For each frame, the driver polls the source of CRCs for new data and calls
+ * this function to add them to the buffer from where userspace reads.
+ */
+int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame,
+			   uint32_t frame, uint32_t *crcs)
+{
+	struct drm_crtc_crc *crc = &crtc->crc;
+	struct drm_crtc_crc_entry *entry;
+	int head, tail;
+
+	assert_spin_locked(&crc->lock);
+
+	/* Caller may not have noticed yet that userspace has stopped reading */
+	if (!crc->opened)
+		return -EINVAL;
+
+	head = crc->head;
+	tail = crc->tail;
+
+	if (CIRC_SPACE(head, tail, DRM_CRC_ENTRIES_NR) < 1) {
+		DRM_ERROR("Overflow of CRC buffer, userspace reads too slow.\n");
+		return -ENOBUFS;
+	}
+
+	entry = &crc->entries[head];
+	entry->frame = frame;
+	entry->has_frame_counter = has_frame;
+	memcpy(&entry->crcs, crcs, sizeof(*crcs) * crc->values_cnt);
+
+	head = (head + 1) & (DRM_CRC_ENTRIES_NR - 1);
+	crc->head = head;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(drm_crtc_add_crc_entry);
diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h
index e66af289a016..abd209863ef4 100644
--- a/drivers/gpu/drm/drm_internal.h
+++ b/drivers/gpu/drm/drm_internal.h
@@ -100,6 +100,9 @@ int drm_debugfs_init(struct drm_minor *minor, int minor_id,
 int drm_debugfs_cleanup(struct drm_minor *minor);
 int drm_debugfs_connector_add(struct drm_connector *connector);
 void drm_debugfs_connector_remove(struct drm_connector *connector);
+int drm_debugfs_crtc_add(struct drm_crtc *crtc);
+void drm_debugfs_crtc_remove(struct drm_crtc *crtc);
+int drm_debugfs_crtc_crc_add(struct drm_crtc *crtc);
 #else
 static inline int drm_debugfs_init(struct drm_minor *minor, int minor_id,
 				   struct dentry *root)
@@ -119,4 +122,17 @@ static inline int drm_debugfs_connector_add(struct drm_connector *connector)
 static inline void drm_debugfs_connector_remove(struct drm_connector *connector)
 {
 }
+
+static inline int drm_debugfs_crtc_add(struct drm_crtc *crtc)
+{
+	return 0;
+}
+static inline void drm_debugfs_crtc_remove(struct drm_crtc *crtc)
+{
+}
+
+static inline int drm_debugfs_crtc_crc_add(struct drm_crtc *crtc)
+{
+	return 0;
+}
 #endif
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 61932f55f788..0908b2cf6c2c 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -47,6 +47,7 @@
 #include <drm/drm_plane.h>
 #include <drm/drm_blend.h>
 #include <drm/drm_color_mgmt.h>
+#include <drm/drm_debugfs_crc.h>
 
 struct drm_device;
 struct drm_mode_set;
@@ -564,6 +565,30 @@ struct drm_crtc_funcs {
 	 * before data structures are torndown.
 	 */
 	void (*early_unregister)(struct drm_crtc *crtc);
+
+	/**
+	 * @set_crc_source:
+	 *
+	 * Changes the source of CRC checksums of frames at the request of
+	 * userspace, typically for testing purposes. The sources available are
+	 * specific of each driver and a %NULL value indicates that CRC
+	 * generation is to be switched off.
+	 *
+	 * When CRC generation is enabled, the driver should call
+	 * drm_crtc_add_crc_entry() at each frame, providing any information
+	 * that characterizes the frame contents in the crcN arguments, as
+	 * provided from the configured source. Drivers must accept a "auto"
+	 * source name that will select a default source for this CRTC.
+	 *
+	 * This callback is optional if the driver does not support any CRC
+	 * generation functionality.
+	 *
+	 * RETURNS:
+	 *
+	 * 0 on success or a negative error code on failure.
+	 */
+	int (*set_crc_source)(struct drm_crtc *crtc, const char *source,
+			      size_t *values_cnt);
 };
 
 /**
@@ -680,6 +705,22 @@ struct drm_crtc {
 	 * context.
 	 */
 	struct drm_modeset_acquire_ctx *acquire_ctx;
+
+#ifdef CONFIG_DEBUG_FS
+	/**
+	 * @debugfs_entry:
+	 *
+	 * Debugfs directory for this CRTC.
+	 */
+	struct dentry *debugfs_entry;
+
+	/**
+	 * @crc:
+	 *
+	 * Configuration settings of CRC capture.
+	 */
+	struct drm_crtc_crc crc;
+#endif
 };
 
 /**
diff --git a/include/drm/drm_debugfs_crc.h b/include/drm/drm_debugfs_crc.h
new file mode 100644
index 000000000000..7d63b1d4adb9
--- /dev/null
+++ b/include/drm/drm_debugfs_crc.h
@@ -0,0 +1,73 @@
+/*
+ * Copyright © 2016 Collabora Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+#ifndef __DRM_DEBUGFS_CRC_H__
+#define __DRM_DEBUGFS_CRC_H__
+
+#define DRM_MAX_CRC_NR		10
+
+/**
+ * struct drm_crtc_crc_entry - entry describing a frame's content
+ * @has_frame_counter: whether the source was able to provide a frame number
+ * @frame: number of the frame this CRC is about, if @has_frame_counter is true
+ * @crc: array of values that characterize the frame
+ */
+struct drm_crtc_crc_entry {
+	bool has_frame_counter;
+	uint32_t frame;
+	uint32_t crcs[DRM_MAX_CRC_NR];
+};
+
+#define DRM_CRC_ENTRIES_NR	128
+
+/**
+ * struct drm_crtc_crc - data supporting CRC capture on a given CRTC
+ * @lock: protects the fields in this struct
+ * @source: name of the currently configured source of CRCs
+ * @opened: whether userspace has opened the data file for reading
+ * @entries: array of entries, with size of %DRM_CRC_ENTRIES_NR
+ * @head: head of circular queue
+ * @tail: tail of circular queue
+ * @values_cnt: number of CRC values per entry, up to %DRM_MAX_CRC_NR
+ * @wq: workqueue used to synchronize reading and writing
+ */
+struct drm_crtc_crc {
+	spinlock_t lock;
+	const char *source;
+	bool opened;
+	struct drm_crtc_crc_entry *entries;
+	int head, tail;
+	size_t values_cnt;
+	wait_queue_head_t wq;
+};
+
+#if defined(CONFIG_DEBUG_FS)
+int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame,
+			   uint32_t frame, uint32_t *crcs);
+#else
+static inline int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame,
+					 uint32_t frame, uint32_t *crcs)
+{
+	return -EINVAL;
+}
+#endif /* defined(CONFIG_DEBUG_FS) */
+
+#endif /* __DRM_DEBUGFS_CRC_H__ */
-- 
2.7.4

Re: [PATCH v11 2/4] drm: Add API for capturing frame CRCs

[Tomeu Vizoso]

Adding Benjamin Gaignard to CC in case he wants to comment on the
usage of the registration functions, as suggested by Daniel Vetter.

Regards,

Tomeu

On 6 October 2016 at 17:21, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote:
> Adds files and directories to debugfs for controlling and reading frame
> CRCs, per CRTC:
>
> dri/0/crtc-0/crc
> dri/0/crtc-0/crc/control
> dri/0/crtc-0/crc/data
>
> Drivers can implement the set_crc_source callback() in drm_crtc_funcs to
> start and stop generating frame CRCs and can add entries to the output
> by calling drm_crtc_add_crc_entry.
>
> v2:
>     - Lots of good fixes suggested by Thierry.
>     - Added documentation.
>     - Changed the debugfs layout.
>     - Moved to allocate the entries circular queue once when frame
>       generation gets enabled for the first time.
> v3:
>     - Use the control file just to select the source, and start and stop
>       capture when the data file is opened and closed, respectively.
>     - Make variable the number of CRC values per entry, per source.
>     - Allocate entries queue each time we start capturing as now there
>       isn't a fixed number of CRC values per entry.
>     - Store the frame counter in the data file as a 8-digit hex number.
>     - For sources that cannot provide useful frame numbers, place
>       XXXXXXXX in the frame field.
>
> v4:
>     - Build only if CONFIG_DEBUG_FS is enabled.
>     - Use memdup_user_nul.
>     - Consolidate calculation of the size of an entry in a helper.
>     - Add 0x prefix to hex numbers in the data file.
>     - Remove unnecessary snprintf and strlen usage in read callback.
>
> v5:
>     - Made the crcs array in drm_crtc_crc_entry fixed-size
>     - Lots of other smaller improvements suggested by Emil Velikov
>
> v7:
>     - Move definition of drm_debugfs_crtc_crc_add to drm_internal.h
>
> v8:
>     - Call debugfs_remove_recursive when we fail to create the minor
>       device
>
> v9:
>     - Register the debugfs directory for a crtc from
>       drm_crtc_register_all()
>
> v10:
>     - Don't let debugfs failures interrupt CRTC registration (Emil
>       Velikov)
>
> v11:
>     - Remove extra brace that broke compilation. Sorry!
>
> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
> ---
>
>  Documentation/gpu/drm-uapi.rst    |   6 +
>  drivers/gpu/drm/Makefile          |   3 +-
>  drivers/gpu/drm/drm_crtc.c        |  34 +++-
>  drivers/gpu/drm/drm_debugfs.c     |  34 +++-
>  drivers/gpu/drm/drm_debugfs_crc.c | 351 ++++++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/drm_internal.h    |  16 ++
>  include/drm/drm_crtc.h            |  41 +++++
>  include/drm/drm_debugfs_crc.h     |  73 ++++++++
>  8 files changed, 555 insertions(+), 3 deletions(-)
>  create mode 100644 drivers/gpu/drm/drm_debugfs_crc.c
>  create mode 100644 include/drm/drm_debugfs_crc.h
>
> diff --git a/Documentation/gpu/drm-uapi.rst b/Documentation/gpu/drm-uapi.rst
> index 1ba301cebe16..de3ac9f90f8f 100644
> --- a/Documentation/gpu/drm-uapi.rst
> +++ b/Documentation/gpu/drm-uapi.rst
> @@ -216,3 +216,9 @@ interfaces. Especially since all hardware-acceleration interfaces to
>  userspace are driver specific for efficiency and other reasons these
>  interfaces can be rather substantial. Hence every driver has its own
>  chapter.
> +
> +Testing and validation
> +======================
> +
> +.. kernel-doc:: drivers/gpu/drm/drm_debugfs_crc.c
> +   :doc: CRC ABI
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index 25c720454017..74579d2e796e 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -9,7 +9,7 @@ drm-y       :=  drm_auth.o drm_bufs.o drm_cache.o \
>                 drm_scatter.o drm_pci.o \
>                 drm_platform.o drm_sysfs.o drm_hashtab.o drm_mm.o \
>                 drm_crtc.o drm_fourcc.o drm_modes.o drm_edid.o \
> -               drm_info.o drm_debugfs.o drm_encoder_slave.o \
> +               drm_info.o drm_encoder_slave.o \
>                 drm_trace_points.o drm_global.o drm_prime.o \
>                 drm_rect.o drm_vma_manager.o drm_flip_work.o \
>                 drm_modeset_lock.o drm_atomic.o drm_bridge.o \
> @@ -23,6 +23,7 @@ drm-$(CONFIG_PCI) += ati_pcigart.o
>  drm-$(CONFIG_DRM_PANEL) += drm_panel.o
>  drm-$(CONFIG_OF) += drm_of.o
>  drm-$(CONFIG_AGP) += drm_agpsupport.o
> +drm-$(CONFIG_DEBUG_FS) += drm_debugfs.o drm_debugfs_crc.o
>
>  drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \
>                 drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o \
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index 2d7bedf28647..60403bf7a4ff 100644
> --- a/drivers/gpu/drm/drm_crtc.c
> +++ b/drivers/gpu/drm/drm_crtc.c
> @@ -40,7 +40,7 @@
>  #include <drm/drm_modeset_lock.h>
>  #include <drm/drm_atomic.h>
>  #include <drm/drm_auth.h>
> -#include <drm/drm_framebuffer.h>
> +#include <drm/drm_debugfs_crc.h>
>
>  #include "drm_crtc_internal.h"
>  #include "drm_internal.h"
> @@ -122,6 +122,10 @@ static int drm_crtc_register_all(struct drm_device *dev)
>         int ret = 0;
>
>         drm_for_each_crtc(crtc, dev) {
> +               if (drm_debugfs_crtc_add(crtc))
> +                       DRM_ERROR("Failed to initialize debugfs entry for CRTC '%s'.\n",
> +                                 crtc->name);
> +
>                 if (crtc->funcs->late_register)
>                         ret = crtc->funcs->late_register(crtc);
>                 if (ret)
> @@ -138,9 +142,29 @@ static void drm_crtc_unregister_all(struct drm_device *dev)
>         drm_for_each_crtc(crtc, dev) {
>                 if (crtc->funcs->early_unregister)
>                         crtc->funcs->early_unregister(crtc);
> +               drm_debugfs_crtc_remove(crtc);
>         }
>  }
>
> +static int drm_crtc_crc_init(struct drm_crtc *crtc)
> +{
> +#ifdef CONFIG_DEBUG_FS
> +       spin_lock_init(&crtc->crc.lock);
> +       init_waitqueue_head(&crtc->crc.wq);
> +       crtc->crc.source = kstrdup("auto", GFP_KERNEL);
> +       if (!crtc->crc.source)
> +               return -ENOMEM;
> +#endif
> +       return 0;
> +}
> +
> +static void drm_crtc_crc_fini(struct drm_crtc *crtc)
> +{
> +#ifdef CONFIG_DEBUG_FS
> +       kfree(crtc->crc.source);
> +#endif
> +}
> +
>  /**
>   * drm_crtc_init_with_planes - Initialise a new CRTC object with
>   *    specified primary and cursor planes.
> @@ -210,6 +234,12 @@ int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc,
>         if (cursor)
>                 cursor->possible_crtcs = 1 << drm_crtc_index(crtc);
>
> +       ret = drm_crtc_crc_init(crtc);
> +       if (ret) {
> +               drm_mode_object_unregister(dev, &crtc->base);
> +               return ret;
> +       }
> +
>         if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
>                 drm_object_attach_property(&crtc->base, config->prop_active, 0);
>                 drm_object_attach_property(&crtc->base, config->prop_mode_id, 0);
> @@ -236,6 +266,8 @@ void drm_crtc_cleanup(struct drm_crtc *crtc)
>          * the indices on the drm_crtc after us in the crtc_list.
>          */
>
> +       drm_crtc_crc_fini(crtc);
> +
>         kfree(crtc->gamma_store);
>         crtc->gamma_store = NULL;
>
> diff --git a/drivers/gpu/drm/drm_debugfs.c b/drivers/gpu/drm/drm_debugfs.c
> index 1205790ed960..800055c39cdb 100644
> --- a/drivers/gpu/drm/drm_debugfs.c
> +++ b/drivers/gpu/drm/drm_debugfs.c
> @@ -415,5 +415,37 @@ void drm_debugfs_connector_remove(struct drm_connector *connector)
>         connector->debugfs_entry = NULL;
>  }
>
> -#endif /* CONFIG_DEBUG_FS */
> +int drm_debugfs_crtc_add(struct drm_crtc *crtc)
> +{
> +       struct drm_minor *minor = crtc->dev->primary;
> +       struct dentry *root;
> +       char *name;
> +
> +       name = kasprintf(GFP_KERNEL, "crtc-%d", crtc->index);
> +       if (!name)
> +               return -ENOMEM;
> +
> +       root = debugfs_create_dir(name, minor->debugfs_root);
> +       kfree(name);
> +       if (!root)
> +               return -ENOMEM;
> +
> +       crtc->debugfs_entry = root;
> +
> +       if (drm_debugfs_crtc_crc_add(crtc))
> +               goto error;
>
> +       return 0;
> +
> +error:
> +       drm_debugfs_crtc_remove(crtc);
> +       return -ENOMEM;
> +}
> +
> +void drm_debugfs_crtc_remove(struct drm_crtc *crtc)
> +{
> +       debugfs_remove_recursive(crtc->debugfs_entry);
> +       crtc->debugfs_entry = NULL;
> +}
> +
> +#endif /* CONFIG_DEBUG_FS */
> diff --git a/drivers/gpu/drm/drm_debugfs_crc.c b/drivers/gpu/drm/drm_debugfs_crc.c
> new file mode 100644
> index 000000000000..4129405d17c0
> --- /dev/null
> +++ b/drivers/gpu/drm/drm_debugfs_crc.c
> @@ -0,0 +1,351 @@
> +/*
> + * Copyright © 2008 Intel Corporation
> + * Copyright © 2016 Collabora Ltd
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> + * IN THE SOFTWARE.
> + *
> + * Based on code from the i915 driver.
> + * Original author: Damien Lespiau <damien.lespiau@intel.com>
> + *
> + */
> +
> +#include <linux/circ_buf.h>
> +#include <linux/ctype.h>
> +#include <linux/debugfs.h>
> +#include <drm/drmP.h>
> +
> +/**
> + * DOC: CRC ABI
> + *
> + * DRM device drivers can provide to userspace CRC information of each frame as
> + * it reached a given hardware component (a "source").
> + *
> + * Userspace can control generation of CRCs in a given CRTC by writing to the
> + * file dri/0/crtc-N/crc/control in debugfs, with N being the index of the CRTC.
> + * Accepted values are source names (which are driver-specific) and the "auto"
> + * keyword, which will let the driver select a default source of frame CRCs
> + * for this CRTC.
> + *
> + * Once frame CRC generation is enabled, userspace can capture them by reading
> + * the dri/0/crtc-N/crc/data file. Each line in that file contains the frame
> + * number in the first field and then a number of unsigned integer fields
> + * containing the CRC data. Fields are separated by a single space and the number
> + * of CRC fields is source-specific.
> + *
> + * Note that though in some cases the CRC is computed in a specified way and on
> + * the frame contents as supplied by userspace (eDP 1.3), in general the CRC
> + * computation is performed in an unspecified way and on frame contents that have
> + * been already processed in also an unspecified way and thus userspace cannot
> + * rely on being able to generate matching CRC values for the frame contents that
> + * it submits. In this general case, the maximum userspace can do is to compare
> + * the reported CRCs of frames that should have the same contents.
> + */
> +
> +static int crc_control_show(struct seq_file *m, void *data)
> +{
> +       struct drm_crtc *crtc = m->private;
> +
> +       seq_printf(m, "%s\n", crtc->crc.source);
> +
> +       return 0;
> +}
> +
> +static int crc_control_open(struct inode *inode, struct file *file)
> +{
> +       struct drm_crtc *crtc = inode->i_private;
> +
> +       return single_open(file, crc_control_show, crtc);
> +}
> +
> +static ssize_t crc_control_write(struct file *file, const char __user *ubuf,
> +                                size_t len, loff_t *offp)
> +{
> +       struct seq_file *m = file->private_data;
> +       struct drm_crtc *crtc = m->private;
> +       struct drm_crtc_crc *crc = &crtc->crc;
> +       char *source;
> +
> +       if (len == 0)
> +               return 0;
> +
> +       if (len > PAGE_SIZE - 1) {
> +               DRM_DEBUG_KMS("Expected < %lu bytes into crtc crc control\n",
> +                             PAGE_SIZE);
> +               return -E2BIG;
> +       }
> +
> +       source = memdup_user_nul(ubuf, len);
> +       if (IS_ERR(source))
> +               return PTR_ERR(source);
> +
> +       if (source[len] == '\n')
> +               source[len] = '\0';
> +
> +       spin_lock_irq(&crc->lock);
> +
> +       if (crc->opened) {
> +               spin_unlock_irq(&crc->lock);
> +               kfree(source);
> +               return -EBUSY;
> +       }
> +
> +       kfree(crc->source);
> +       crc->source = source;
> +
> +       spin_unlock_irq(&crc->lock);
> +
> +       *offp += len;
> +       return len;
> +}
> +
> +const struct file_operations drm_crtc_crc_control_fops = {
> +       .owner = THIS_MODULE,
> +       .open = crc_control_open,
> +       .read = seq_read,
> +       .llseek = seq_lseek,
> +       .release = single_release,
> +       .write = crc_control_write
> +};
> +
> +static int crtc_crc_open(struct inode *inode, struct file *filep)
> +{
> +       struct drm_crtc *crtc = inode->i_private;
> +       struct drm_crtc_crc *crc = &crtc->crc;
> +       struct drm_crtc_crc_entry *entries = NULL;
> +       size_t values_cnt;
> +       int ret;
> +
> +       if (crc->opened)
> +               return -EBUSY;
> +
> +       ret = crtc->funcs->set_crc_source(crtc, crc->source, &values_cnt);
> +       if (ret)
> +               return ret;
> +
> +       if (WARN_ON(values_cnt > DRM_MAX_CRC_NR)) {
> +               ret = -EINVAL;
> +               goto err_disable;
> +       }
> +
> +       if (WARN_ON(values_cnt == 0)) {
> +               ret = -EINVAL;
> +               goto err_disable;
> +       }
> +
> +       entries = kcalloc(DRM_CRC_ENTRIES_NR, sizeof(*entries), GFP_KERNEL);
> +       if (!entries) {
> +               ret = -ENOMEM;
> +               goto err_disable;
> +       }
> +
> +       spin_lock_irq(&crc->lock);
> +       crc->entries = entries;
> +       crc->values_cnt = values_cnt;
> +       crc->opened = true;
> +       spin_unlock_irq(&crc->lock);
> +
> +       return 0;
> +
> +err_disable:
> +       crtc->funcs->set_crc_source(crtc, NULL, &values_cnt);
> +       return ret;
> +}
> +
> +static int crtc_crc_release(struct inode *inode, struct file *filep)
> +{
> +       struct drm_crtc *crtc = filep->f_inode->i_private;
> +       struct drm_crtc_crc *crc = &crtc->crc;
> +       size_t values_cnt;
> +
> +       spin_lock_irq(&crc->lock);
> +       kfree(crc->entries);
> +       crc->entries = NULL;
> +       crc->head = 0;
> +       crc->tail = 0;
> +       crc->values_cnt = 0;
> +       crc->opened = false;
> +       spin_unlock_irq(&crc->lock);
> +
> +       crtc->funcs->set_crc_source(crtc, NULL, &values_cnt);
> +
> +       return 0;
> +}
> +
> +static int crtc_crc_data_count(struct drm_crtc_crc *crc)
> +{
> +       assert_spin_locked(&crc->lock);
> +       return CIRC_CNT(crc->head, crc->tail, DRM_CRC_ENTRIES_NR);
> +}
> +
> +/*
> + * 1 frame field of 10 chars plus a number of CRC fields of 10 chars each, space
> + * separated, with a newline at the end and null-terminated.
> + */
> +#define LINE_LEN(values_cnt)   (10 + 11 * values_cnt + 1 + 1)
> +#define MAX_LINE_LEN           (LINE_LEN(DRM_MAX_CRC_NR))
> +
> +static ssize_t crtc_crc_read(struct file *filep, char __user *user_buf,
> +                            size_t count, loff_t *pos)
> +{
> +       struct drm_crtc *crtc = filep->f_inode->i_private;
> +       struct drm_crtc_crc *crc = &crtc->crc;
> +       struct drm_crtc_crc_entry *entry;
> +       char buf[MAX_LINE_LEN];
> +       int ret, i;
> +
> +       spin_lock_irq(&crc->lock);
> +
> +       if (!crc->source) {
> +               spin_unlock_irq(&crc->lock);
> +               return 0;
> +       }
> +
> +       /* Nothing to read? */
> +       while (crtc_crc_data_count(crc) == 0) {
> +               if (filep->f_flags & O_NONBLOCK) {
> +                       spin_unlock_irq(&crc->lock);
> +                       return -EAGAIN;
> +               }
> +
> +               ret = wait_event_interruptible_lock_irq(crc->wq,
> +                                                       crtc_crc_data_count(crc),
> +                                                       crc->lock);
> +               if (ret) {
> +                       spin_unlock_irq(&crc->lock);
> +                       return ret;
> +               }
> +       }
> +
> +       /* We know we have an entry to be read */
> +       entry = &crc->entries[crc->tail];
> +
> +       if (count < LINE_LEN(crc->values_cnt)) {
> +               spin_unlock_irq(&crc->lock);
> +               return -EINVAL;
> +       }
> +
> +       BUILD_BUG_ON_NOT_POWER_OF_2(DRM_CRC_ENTRIES_NR);
> +       crc->tail = (crc->tail + 1) & (DRM_CRC_ENTRIES_NR - 1);
> +
> +       spin_unlock_irq(&crc->lock);
> +
> +       if (entry->has_frame_counter)
> +               sprintf(buf, "0x%08x", entry->frame);
> +       else
> +               sprintf(buf, "XXXXXXXXXX");
> +
> +       for (i = 0; i < crc->values_cnt; i++)
> +               sprintf(buf + 10 + i * 11, " 0x%08x", entry->crcs[i]);
> +       sprintf(buf + 10 + crc->values_cnt * 11, "\n");
> +
> +       if (copy_to_user(user_buf, buf, LINE_LEN(crc->values_cnt)))
> +               return -EFAULT;
> +
> +       return LINE_LEN(crc->values_cnt);
> +}
> +
> +const struct file_operations drm_crtc_crc_data_fops = {
> +       .owner = THIS_MODULE,
> +       .open = crtc_crc_open,
> +       .read = crtc_crc_read,
> +       .release = crtc_crc_release,
> +};
> +
> +/**
> + * drm_debugfs_crtc_crc_add - Add files to debugfs for capture of frame CRCs
> + * @crtc: CRTC to whom the frames will belong
> + *
> + * Adds files to debugfs directory that allows userspace to control the
> + * generation of frame CRCs and to read them.
> + *
> + * Returns:
> + * Zero on success, error code on failure.
> + */
> +int drm_debugfs_crtc_crc_add(struct drm_crtc *crtc)
> +{
> +       struct dentry *crc_ent, *ent;
> +
> +       if (!crtc->funcs->set_crc_source)
> +               return 0;
> +
> +       crc_ent = debugfs_create_dir("crc", crtc->debugfs_entry);
> +       if (!crc_ent)
> +               return -ENOMEM;
> +
> +       ent = debugfs_create_file("control", S_IRUGO, crc_ent, crtc,
> +                                 &drm_crtc_crc_control_fops);
> +       if (!ent)
> +               goto error;
> +
> +       ent = debugfs_create_file("data", S_IRUGO, crc_ent, crtc,
> +                                 &drm_crtc_crc_data_fops);
> +       if (!ent)
> +               goto error;
> +
> +       return 0;
> +
> +error:
> +       debugfs_remove_recursive(crc_ent);
> +
> +       return -ENOMEM;
> +}
> +
> +/**
> + * drm_crtc_add_crc_entry - Add entry with CRC information for a frame
> + * @crtc: CRTC to which the frame belongs
> + * @has_frame: whether this entry has a frame number to go with
> + * @frame: number of the frame these CRCs are about
> + * @crcs: array of CRC values, with length matching #drm_crtc_crc.values_cnt
> + *
> + * For each frame, the driver polls the source of CRCs for new data and calls
> + * this function to add them to the buffer from where userspace reads.
> + */
> +int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame,
> +                          uint32_t frame, uint32_t *crcs)
> +{
> +       struct drm_crtc_crc *crc = &crtc->crc;
> +       struct drm_crtc_crc_entry *entry;
> +       int head, tail;
> +
> +       assert_spin_locked(&crc->lock);
> +
> +       /* Caller may not have noticed yet that userspace has stopped reading */
> +       if (!crc->opened)
> +               return -EINVAL;
> +
> +       head = crc->head;
> +       tail = crc->tail;
> +
> +       if (CIRC_SPACE(head, tail, DRM_CRC_ENTRIES_NR) < 1) {
> +               DRM_ERROR("Overflow of CRC buffer, userspace reads too slow.\n");
> +               return -ENOBUFS;
> +       }
> +
> +       entry = &crc->entries[head];
> +       entry->frame = frame;
> +       entry->has_frame_counter = has_frame;
> +       memcpy(&entry->crcs, crcs, sizeof(*crcs) * crc->values_cnt);
> +
> +       head = (head + 1) & (DRM_CRC_ENTRIES_NR - 1);
> +       crc->head = head;
> +
> +       return 0;
> +}
> +EXPORT_SYMBOL_GPL(drm_crtc_add_crc_entry);
> diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h
> index e66af289a016..abd209863ef4 100644
> --- a/drivers/gpu/drm/drm_internal.h
> +++ b/drivers/gpu/drm/drm_internal.h
> @@ -100,6 +100,9 @@ int drm_debugfs_init(struct drm_minor *minor, int minor_id,
>  int drm_debugfs_cleanup(struct drm_minor *minor);
>  int drm_debugfs_connector_add(struct drm_connector *connector);
>  void drm_debugfs_connector_remove(struct drm_connector *connector);
> +int drm_debugfs_crtc_add(struct drm_crtc *crtc);
> +void drm_debugfs_crtc_remove(struct drm_crtc *crtc);
> +int drm_debugfs_crtc_crc_add(struct drm_crtc *crtc);
>  #else
>  static inline int drm_debugfs_init(struct drm_minor *minor, int minor_id,
>                                    struct dentry *root)
> @@ -119,4 +122,17 @@ static inline int drm_debugfs_connector_add(struct drm_connector *connector)
>  static inline void drm_debugfs_connector_remove(struct drm_connector *connector)
>  {
>  }
> +
> +static inline int drm_debugfs_crtc_add(struct drm_crtc *crtc)
> +{
> +       return 0;
> +}
> +static inline void drm_debugfs_crtc_remove(struct drm_crtc *crtc)
> +{
> +}
> +
> +static inline int drm_debugfs_crtc_crc_add(struct drm_crtc *crtc)
> +{
> +       return 0;
> +}
>  #endif
> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> index 61932f55f788..0908b2cf6c2c 100644
> --- a/include/drm/drm_crtc.h
> +++ b/include/drm/drm_crtc.h
> @@ -47,6 +47,7 @@
>  #include <drm/drm_plane.h>
>  #include <drm/drm_blend.h>
>  #include <drm/drm_color_mgmt.h>
> +#include <drm/drm_debugfs_crc.h>
>
>  struct drm_device;
>  struct drm_mode_set;
> @@ -564,6 +565,30 @@ struct drm_crtc_funcs {
>          * before data structures are torndown.
>          */
>         void (*early_unregister)(struct drm_crtc *crtc);
> +
> +       /**
> +        * @set_crc_source:
> +        *
> +        * Changes the source of CRC checksums of frames at the request of
> +        * userspace, typically for testing purposes. The sources available are
> +        * specific of each driver and a %NULL value indicates that CRC
> +        * generation is to be switched off.
> +        *
> +        * When CRC generation is enabled, the driver should call
> +        * drm_crtc_add_crc_entry() at each frame, providing any information
> +        * that characterizes the frame contents in the crcN arguments, as
> +        * provided from the configured source. Drivers must accept a "auto"
> +        * source name that will select a default source for this CRTC.
> +        *
> +        * This callback is optional if the driver does not support any CRC
> +        * generation functionality.
> +        *
> +        * RETURNS:
> +        *
> +        * 0 on success or a negative error code on failure.
> +        */
> +       int (*set_crc_source)(struct drm_crtc *crtc, const char *source,
> +                             size_t *values_cnt);
>  };
>
>  /**
> @@ -680,6 +705,22 @@ struct drm_crtc {
>          * context.
>          */
>         struct drm_modeset_acquire_ctx *acquire_ctx;
> +
> +#ifdef CONFIG_DEBUG_FS
> +       /**
> +        * @debugfs_entry:
> +        *
> +        * Debugfs directory for this CRTC.
> +        */
> +       struct dentry *debugfs_entry;
> +
> +       /**
> +        * @crc:
> +        *
> +        * Configuration settings of CRC capture.
> +        */
> +       struct drm_crtc_crc crc;
> +#endif
>  };
>
>  /**
> diff --git a/include/drm/drm_debugfs_crc.h b/include/drm/drm_debugfs_crc.h
> new file mode 100644
> index 000000000000..7d63b1d4adb9
> --- /dev/null
> +++ b/include/drm/drm_debugfs_crc.h
> @@ -0,0 +1,73 @@
> +/*
> + * Copyright © 2016 Collabora Ltd.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
> + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
> + * OTHER DEALINGS IN THE SOFTWARE.
> + */
> +#ifndef __DRM_DEBUGFS_CRC_H__
> +#define __DRM_DEBUGFS_CRC_H__
> +
> +#define DRM_MAX_CRC_NR         10
> +
> +/**
> + * struct drm_crtc_crc_entry - entry describing a frame's content
> + * @has_frame_counter: whether the source was able to provide a frame number
> + * @frame: number of the frame this CRC is about, if @has_frame_counter is true
> + * @crc: array of values that characterize the frame
> + */
> +struct drm_crtc_crc_entry {
> +       bool has_frame_counter;
> +       uint32_t frame;
> +       uint32_t crcs[DRM_MAX_CRC_NR];
> +};
> +
> +#define DRM_CRC_ENTRIES_NR     128
> +
> +/**
> + * struct drm_crtc_crc - data supporting CRC capture on a given CRTC
> + * @lock: protects the fields in this struct
> + * @source: name of the currently configured source of CRCs
> + * @opened: whether userspace has opened the data file for reading
> + * @entries: array of entries, with size of %DRM_CRC_ENTRIES_NR
> + * @head: head of circular queue
> + * @tail: tail of circular queue
> + * @values_cnt: number of CRC values per entry, up to %DRM_MAX_CRC_NR
> + * @wq: workqueue used to synchronize reading and writing
> + */
> +struct drm_crtc_crc {
> +       spinlock_t lock;
> +       const char *source;
> +       bool opened;
> +       struct drm_crtc_crc_entry *entries;
> +       int head, tail;
> +       size_t values_cnt;
> +       wait_queue_head_t wq;
> +};
> +
> +#if defined(CONFIG_DEBUG_FS)
> +int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame,
> +                          uint32_t frame, uint32_t *crcs);
> +#else
> +static inline int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame,
> +                                        uint32_t frame, uint32_t *crcs)
> +{
> +       return -EINVAL;
> +}
> +#endif /* defined(CONFIG_DEBUG_FS) */
> +
> +#endif /* __DRM_DEBUGFS_CRC_H__ */
> --
> 2.7.4
>

Re: [PATCH v11 2/4] drm: Add API for capturing frame CRCs

[Emil Velikov]

On 6 October 2016 at 16:21, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote:
> Adds files and directories to debugfs for controlling and reading frame
> CRCs, per CRTC:
>
> dri/0/crtc-0/crc
> dri/0/crtc-0/crc/control
> dri/0/crtc-0/crc/data
>
> Drivers can implement the set_crc_source callback() in drm_crtc_funcs to
> start and stop generating frame CRCs and can add entries to the output
> by calling drm_crtc_add_crc_entry.
>
> v2:
>     - Lots of good fixes suggested by Thierry.
>     - Added documentation.
>     - Changed the debugfs layout.
>     - Moved to allocate the entries circular queue once when frame
>       generation gets enabled for the first time.
> v3:
>     - Use the control file just to select the source, and start and stop
>       capture when the data file is opened and closed, respectively.
>     - Make variable the number of CRC values per entry, per source.
>     - Allocate entries queue each time we start capturing as now there
>       isn't a fixed number of CRC values per entry.
>     - Store the frame counter in the data file as a 8-digit hex number.
>     - For sources that cannot provide useful frame numbers, place
>       XXXXXXXX in the frame field.
>
> v4:
>     - Build only if CONFIG_DEBUG_FS is enabled.
>     - Use memdup_user_nul.
>     - Consolidate calculation of the size of an entry in a helper.
>     - Add 0x prefix to hex numbers in the data file.
>     - Remove unnecessary snprintf and strlen usage in read callback.
>
> v5:
>     - Made the crcs array in drm_crtc_crc_entry fixed-size
>     - Lots of other smaller improvements suggested by Emil Velikov
>
> v7:
>     - Move definition of drm_debugfs_crtc_crc_add to drm_internal.h
>
> v8:
>     - Call debugfs_remove_recursive when we fail to create the minor
>       device
>
> v9:
>     - Register the debugfs directory for a crtc from
>       drm_crtc_register_all()
>
> v10:
>     - Don't let debugfs failures interrupt CRTC registration (Emil
>       Velikov)
>
> v11:
>     - Remove extra brace that broke compilation. Sorry!
>
> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>

Reviewed-by: Emil Velikov <emil.velikov@collabora.com>

Emil

Re: [PATCH v11 2/4] drm: Add API for capturing frame CRCs

[Benjamin Gaignard]

Hello,

I have been able to test it on my setup and, after implementing
set_crc_source function,
I have crc/data and crc/control entries for each of my crtc.

"cat /sys/kernel/debug/dri/0/crtc-0/crc/data" is blocking but I'm
really sure of my driver implementation...

Anyway you could add my ack on this patch

Regards,
Benjamin

2016-10-10 15:12 GMT+02:00 Emil Velikov <emil.l.velikov@gmail.com>:
> On 6 October 2016 at 16:21, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote:
>> Adds files and directories to debugfs for controlling and reading frame
>> CRCs, per CRTC:
>>
>> dri/0/crtc-0/crc
>> dri/0/crtc-0/crc/control
>> dri/0/crtc-0/crc/data
>>
>> Drivers can implement the set_crc_source callback() in drm_crtc_funcs to
>> start and stop generating frame CRCs and can add entries to the output
>> by calling drm_crtc_add_crc_entry.
>>
>> v2:
>>     - Lots of good fixes suggested by Thierry.
>>     - Added documentation.
>>     - Changed the debugfs layout.
>>     - Moved to allocate the entries circular queue once when frame
>>       generation gets enabled for the first time.
>> v3:
>>     - Use the control file just to select the source, and start and stop
>>       capture when the data file is opened and closed, respectively.
>>     - Make variable the number of CRC values per entry, per source.
>>     - Allocate entries queue each time we start capturing as now there
>>       isn't a fixed number of CRC values per entry.
>>     - Store the frame counter in the data file as a 8-digit hex number.
>>     - For sources that cannot provide useful frame numbers, place
>>       XXXXXXXX in the frame field.
>>
>> v4:
>>     - Build only if CONFIG_DEBUG_FS is enabled.
>>     - Use memdup_user_nul.
>>     - Consolidate calculation of the size of an entry in a helper.
>>     - Add 0x prefix to hex numbers in the data file.
>>     - Remove unnecessary snprintf and strlen usage in read callback.
>>
>> v5:
>>     - Made the crcs array in drm_crtc_crc_entry fixed-size
>>     - Lots of other smaller improvements suggested by Emil Velikov
>>
>> v7:
>>     - Move definition of drm_debugfs_crtc_crc_add to drm_internal.h
>>
>> v8:
>>     - Call debugfs_remove_recursive when we fail to create the minor
>>       device
>>
>> v9:
>>     - Register the debugfs directory for a crtc from
>>       drm_crtc_register_all()
>>
>> v10:
>>     - Don't let debugfs failures interrupt CRTC registration (Emil
>>       Velikov)
>>
>> v11:
>>     - Remove extra brace that broke compilation. Sorry!
>>
>> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
>
> Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
>
> Emil
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel



-- 
Benjamin Gaignard

Graphic Study Group

Linaro.org │ Open source software for ARM SoCs

Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v11 2/4] drm: Add API for capturing frame CRCs

[Daniel Vetter]

On Thu, Oct 06, 2016 at 05:21:06PM +0200, Tomeu Vizoso wrote:
> Adds files and directories to debugfs for controlling and reading frame
> CRCs, per CRTC:
> 
> dri/0/crtc-0/crc
> dri/0/crtc-0/crc/control
> dri/0/crtc-0/crc/data
> 
> Drivers can implement the set_crc_source callback() in drm_crtc_funcs to
> start and stop generating frame CRCs and can add entries to the output
> by calling drm_crtc_add_crc_entry.
> 
> v2:
>     - Lots of good fixes suggested by Thierry.
>     - Added documentation.
>     - Changed the debugfs layout.
>     - Moved to allocate the entries circular queue once when frame
>       generation gets enabled for the first time.
> v3:
>     - Use the control file just to select the source, and start and stop
>       capture when the data file is opened and closed, respectively.
>     - Make variable the number of CRC values per entry, per source.
>     - Allocate entries queue each time we start capturing as now there
>       isn't a fixed number of CRC values per entry.
>     - Store the frame counter in the data file as a 8-digit hex number.
>     - For sources that cannot provide useful frame numbers, place
>       XXXXXXXX in the frame field.
> 
> v4:
>     - Build only if CONFIG_DEBUG_FS is enabled.
>     - Use memdup_user_nul.
>     - Consolidate calculation of the size of an entry in a helper.
>     - Add 0x prefix to hex numbers in the data file.
>     - Remove unnecessary snprintf and strlen usage in read callback.
> 
> v5:
>     - Made the crcs array in drm_crtc_crc_entry fixed-size
>     - Lots of other smaller improvements suggested by Emil Velikov
> 
> v7:
>     - Move definition of drm_debugfs_crtc_crc_add to drm_internal.h
> 
> v8:
>     - Call debugfs_remove_recursive when we fail to create the minor
>       device
> 
> v9:
>     - Register the debugfs directory for a crtc from
>       drm_crtc_register_all()
> 
> v10:
>     - Don't let debugfs failures interrupt CRTC registration (Emil
>       Velikov)
> 
> v11:
>     - Remove extra brace that broke compilation. Sorry!
> 
> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
> ---
> 
>  Documentation/gpu/drm-uapi.rst    |   6 +
>  drivers/gpu/drm/Makefile          |   3 +-
>  drivers/gpu/drm/drm_crtc.c        |  34 +++-
>  drivers/gpu/drm/drm_debugfs.c     |  34 +++-
>  drivers/gpu/drm/drm_debugfs_crc.c | 351 ++++++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/drm_internal.h    |  16 ++
>  include/drm/drm_crtc.h            |  41 +++++
>  include/drm/drm_debugfs_crc.h     |  73 ++++++++
>  8 files changed, 555 insertions(+), 3 deletions(-)
>  create mode 100644 drivers/gpu/drm/drm_debugfs_crc.c
>  create mode 100644 include/drm/drm_debugfs_crc.h
> 
> diff --git a/Documentation/gpu/drm-uapi.rst b/Documentation/gpu/drm-uapi.rst
> index 1ba301cebe16..de3ac9f90f8f 100644
> --- a/Documentation/gpu/drm-uapi.rst
> +++ b/Documentation/gpu/drm-uapi.rst
> @@ -216,3 +216,9 @@ interfaces. Especially since all hardware-acceleration interfaces to
>  userspace are driver specific for efficiency and other reasons these
>  interfaces can be rather substantial. Hence every driver has its own
>  chapter.
> +
> +Testing and validation
> +======================
> +
> +.. kernel-doc:: drivers/gpu/drm/drm_debugfs_crc.c
> +   :doc: CRC ABI

Just realized that you don't pull in the abi docs itself drom
drm_debugfs_crc.[hc]. Can you pls address that in a follow-up patch?

Merged this one here meanwhile to drm-misc. I couldn't apply the i915
patches to drm-misc, stuff is diverging too much :( I think it's better to
get the i915 patches in once I've done a backmerge from drm-misc to
drm-intel.

Thanks, Daniel

> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index 25c720454017..74579d2e796e 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -9,7 +9,7 @@ drm-y       :=	drm_auth.o drm_bufs.o drm_cache.o \
>  		drm_scatter.o drm_pci.o \
>  		drm_platform.o drm_sysfs.o drm_hashtab.o drm_mm.o \
>  		drm_crtc.o drm_fourcc.o drm_modes.o drm_edid.o \
> -		drm_info.o drm_debugfs.o drm_encoder_slave.o \
> +		drm_info.o drm_encoder_slave.o \
>  		drm_trace_points.o drm_global.o drm_prime.o \
>  		drm_rect.o drm_vma_manager.o drm_flip_work.o \
>  		drm_modeset_lock.o drm_atomic.o drm_bridge.o \
> @@ -23,6 +23,7 @@ drm-$(CONFIG_PCI) += ati_pcigart.o
>  drm-$(CONFIG_DRM_PANEL) += drm_panel.o
>  drm-$(CONFIG_OF) += drm_of.o
>  drm-$(CONFIG_AGP) += drm_agpsupport.o
> +drm-$(CONFIG_DEBUG_FS) += drm_debugfs.o drm_debugfs_crc.o
>  
>  drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \
>  		drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o \
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index 2d7bedf28647..60403bf7a4ff 100644
> --- a/drivers/gpu/drm/drm_crtc.c
> +++ b/drivers/gpu/drm/drm_crtc.c
> @@ -40,7 +40,7 @@
>  #include <drm/drm_modeset_lock.h>
>  #include <drm/drm_atomic.h>
>  #include <drm/drm_auth.h>
> -#include <drm/drm_framebuffer.h>
> +#include <drm/drm_debugfs_crc.h>
>  
>  #include "drm_crtc_internal.h"
>  #include "drm_internal.h"
> @@ -122,6 +122,10 @@ static int drm_crtc_register_all(struct drm_device *dev)
>  	int ret = 0;
>  
>  	drm_for_each_crtc(crtc, dev) {
> +		if (drm_debugfs_crtc_add(crtc))
> +			DRM_ERROR("Failed to initialize debugfs entry for CRTC '%s'.\n",
> +				  crtc->name);
> +
>  		if (crtc->funcs->late_register)
>  			ret = crtc->funcs->late_register(crtc);
>  		if (ret)
> @@ -138,9 +142,29 @@ static void drm_crtc_unregister_all(struct drm_device *dev)
>  	drm_for_each_crtc(crtc, dev) {
>  		if (crtc->funcs->early_unregister)
>  			crtc->funcs->early_unregister(crtc);
> +		drm_debugfs_crtc_remove(crtc);
>  	}
>  }
>  
> +static int drm_crtc_crc_init(struct drm_crtc *crtc)
> +{
> +#ifdef CONFIG_DEBUG_FS
> +	spin_lock_init(&crtc->crc.lock);
> +	init_waitqueue_head(&crtc->crc.wq);
> +	crtc->crc.source = kstrdup("auto", GFP_KERNEL);
> +	if (!crtc->crc.source)
> +		return -ENOMEM;
> +#endif
> +	return 0;
> +}
> +
> +static void drm_crtc_crc_fini(struct drm_crtc *crtc)
> +{
> +#ifdef CONFIG_DEBUG_FS
> +	kfree(crtc->crc.source);
> +#endif
> +}
> +
>  /**
>   * drm_crtc_init_with_planes - Initialise a new CRTC object with
>   *    specified primary and cursor planes.
> @@ -210,6 +234,12 @@ int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc,
>  	if (cursor)
>  		cursor->possible_crtcs = 1 << drm_crtc_index(crtc);
>  
> +	ret = drm_crtc_crc_init(crtc);
> +	if (ret) {
> +		drm_mode_object_unregister(dev, &crtc->base);
> +		return ret;
> +	}
> +
>  	if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
>  		drm_object_attach_property(&crtc->base, config->prop_active, 0);
>  		drm_object_attach_property(&crtc->base, config->prop_mode_id, 0);
> @@ -236,6 +266,8 @@ void drm_crtc_cleanup(struct drm_crtc *crtc)
>  	 * the indices on the drm_crtc after us in the crtc_list.
>  	 */
>  
> +	drm_crtc_crc_fini(crtc);
> +
>  	kfree(crtc->gamma_store);
>  	crtc->gamma_store = NULL;
>  
> diff --git a/drivers/gpu/drm/drm_debugfs.c b/drivers/gpu/drm/drm_debugfs.c
> index 1205790ed960..800055c39cdb 100644
> --- a/drivers/gpu/drm/drm_debugfs.c
> +++ b/drivers/gpu/drm/drm_debugfs.c
> @@ -415,5 +415,37 @@ void drm_debugfs_connector_remove(struct drm_connector *connector)
>  	connector->debugfs_entry = NULL;
>  }
>  
> -#endif /* CONFIG_DEBUG_FS */
> +int drm_debugfs_crtc_add(struct drm_crtc *crtc)
> +{
> +	struct drm_minor *minor = crtc->dev->primary;
> +	struct dentry *root;
> +	char *name;
> +
> +	name = kasprintf(GFP_KERNEL, "crtc-%d", crtc->index);
> +	if (!name)
> +		return -ENOMEM;
> +
> +	root = debugfs_create_dir(name, minor->debugfs_root);
> +	kfree(name);
> +	if (!root)
> +		return -ENOMEM;
> +
> +	crtc->debugfs_entry = root;
> +
> +	if (drm_debugfs_crtc_crc_add(crtc))
> +		goto error;
>  
> +	return 0;
> +
> +error:
> +	drm_debugfs_crtc_remove(crtc);
> +	return -ENOMEM;
> +}
> +
> +void drm_debugfs_crtc_remove(struct drm_crtc *crtc)
> +{
> +	debugfs_remove_recursive(crtc->debugfs_entry);
> +	crtc->debugfs_entry = NULL;
> +}
> +
> +#endif /* CONFIG_DEBUG_FS */
> diff --git a/drivers/gpu/drm/drm_debugfs_crc.c b/drivers/gpu/drm/drm_debugfs_crc.c
> new file mode 100644
> index 000000000000..4129405d17c0
> --- /dev/null
> +++ b/drivers/gpu/drm/drm_debugfs_crc.c
> @@ -0,0 +1,351 @@
> +/*
> + * Copyright © 2008 Intel Corporation
> + * Copyright © 2016 Collabora Ltd
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> + * IN THE SOFTWARE.
> + *
> + * Based on code from the i915 driver.
> + * Original author: Damien Lespiau <damien.lespiau@intel.com>
> + *
> + */
> +
> +#include <linux/circ_buf.h>
> +#include <linux/ctype.h>
> +#include <linux/debugfs.h>
> +#include <drm/drmP.h>
> +
> +/**
> + * DOC: CRC ABI
> + *
> + * DRM device drivers can provide to userspace CRC information of each frame as
> + * it reached a given hardware component (a "source").
> + *
> + * Userspace can control generation of CRCs in a given CRTC by writing to the
> + * file dri/0/crtc-N/crc/control in debugfs, with N being the index of the CRTC.
> + * Accepted values are source names (which are driver-specific) and the "auto"
> + * keyword, which will let the driver select a default source of frame CRCs
> + * for this CRTC.
> + *
> + * Once frame CRC generation is enabled, userspace can capture them by reading
> + * the dri/0/crtc-N/crc/data file. Each line in that file contains the frame
> + * number in the first field and then a number of unsigned integer fields
> + * containing the CRC data. Fields are separated by a single space and the number
> + * of CRC fields is source-specific.
> + *
> + * Note that though in some cases the CRC is computed in a specified way and on
> + * the frame contents as supplied by userspace (eDP 1.3), in general the CRC
> + * computation is performed in an unspecified way and on frame contents that have
> + * been already processed in also an unspecified way and thus userspace cannot
> + * rely on being able to generate matching CRC values for the frame contents that
> + * it submits. In this general case, the maximum userspace can do is to compare
> + * the reported CRCs of frames that should have the same contents.
> + */
> +
> +static int crc_control_show(struct seq_file *m, void *data)
> +{
> +	struct drm_crtc *crtc = m->private;
> +
> +	seq_printf(m, "%s\n", crtc->crc.source);
> +
> +	return 0;
> +}
> +
> +static int crc_control_open(struct inode *inode, struct file *file)
> +{
> +	struct drm_crtc *crtc = inode->i_private;
> +
> +	return single_open(file, crc_control_show, crtc);
> +}
> +
> +static ssize_t crc_control_write(struct file *file, const char __user *ubuf,
> +				 size_t len, loff_t *offp)
> +{
> +	struct seq_file *m = file->private_data;
> +	struct drm_crtc *crtc = m->private;
> +	struct drm_crtc_crc *crc = &crtc->crc;
> +	char *source;
> +
> +	if (len == 0)
> +		return 0;
> +
> +	if (len > PAGE_SIZE - 1) {
> +		DRM_DEBUG_KMS("Expected < %lu bytes into crtc crc control\n",
> +			      PAGE_SIZE);
> +		return -E2BIG;
> +	}
> +
> +	source = memdup_user_nul(ubuf, len);
> +	if (IS_ERR(source))
> +		return PTR_ERR(source);
> +
> +	if (source[len] == '\n')
> +		source[len] = '\0';
> +
> +	spin_lock_irq(&crc->lock);
> +
> +	if (crc->opened) {
> +		spin_unlock_irq(&crc->lock);
> +		kfree(source);
> +		return -EBUSY;
> +	}
> +
> +	kfree(crc->source);
> +	crc->source = source;
> +
> +	spin_unlock_irq(&crc->lock);
> +
> +	*offp += len;
> +	return len;
> +}
> +
> +const struct file_operations drm_crtc_crc_control_fops = {
> +	.owner = THIS_MODULE,
> +	.open = crc_control_open,
> +	.read = seq_read,
> +	.llseek = seq_lseek,
> +	.release = single_release,
> +	.write = crc_control_write
> +};
> +
> +static int crtc_crc_open(struct inode *inode, struct file *filep)
> +{
> +	struct drm_crtc *crtc = inode->i_private;
> +	struct drm_crtc_crc *crc = &crtc->crc;
> +	struct drm_crtc_crc_entry *entries = NULL;
> +	size_t values_cnt;
> +	int ret;
> +
> +	if (crc->opened)
> +		return -EBUSY;
> +
> +	ret = crtc->funcs->set_crc_source(crtc, crc->source, &values_cnt);
> +	if (ret)
> +		return ret;
> +
> +	if (WARN_ON(values_cnt > DRM_MAX_CRC_NR)) {
> +		ret = -EINVAL;
> +		goto err_disable;
> +	}
> +
> +	if (WARN_ON(values_cnt == 0)) {
> +		ret = -EINVAL;
> +		goto err_disable;
> +	}
> +
> +	entries = kcalloc(DRM_CRC_ENTRIES_NR, sizeof(*entries), GFP_KERNEL);
> +	if (!entries) {
> +		ret = -ENOMEM;
> +		goto err_disable;
> +	}
> +
> +	spin_lock_irq(&crc->lock);
> +	crc->entries = entries;
> +	crc->values_cnt = values_cnt;
> +	crc->opened = true;
> +	spin_unlock_irq(&crc->lock);
> +
> +	return 0;
> +
> +err_disable:
> +	crtc->funcs->set_crc_source(crtc, NULL, &values_cnt);
> +	return ret;
> +}
> +
> +static int crtc_crc_release(struct inode *inode, struct file *filep)
> +{
> +	struct drm_crtc *crtc = filep->f_inode->i_private;
> +	struct drm_crtc_crc *crc = &crtc->crc;
> +	size_t values_cnt;
> +
> +	spin_lock_irq(&crc->lock);
> +	kfree(crc->entries);
> +	crc->entries = NULL;
> +	crc->head = 0;
> +	crc->tail = 0;
> +	crc->values_cnt = 0;
> +	crc->opened = false;
> +	spin_unlock_irq(&crc->lock);
> +
> +	crtc->funcs->set_crc_source(crtc, NULL, &values_cnt);
> +
> +	return 0;
> +}
> +
> +static int crtc_crc_data_count(struct drm_crtc_crc *crc)
> +{
> +	assert_spin_locked(&crc->lock);
> +	return CIRC_CNT(crc->head, crc->tail, DRM_CRC_ENTRIES_NR);
> +}
> +
> +/*
> + * 1 frame field of 10 chars plus a number of CRC fields of 10 chars each, space
> + * separated, with a newline at the end and null-terminated.
> + */
> +#define LINE_LEN(values_cnt)	(10 + 11 * values_cnt + 1 + 1)
> +#define MAX_LINE_LEN		(LINE_LEN(DRM_MAX_CRC_NR))
> +
> +static ssize_t crtc_crc_read(struct file *filep, char __user *user_buf,
> +			     size_t count, loff_t *pos)
> +{
> +	struct drm_crtc *crtc = filep->f_inode->i_private;
> +	struct drm_crtc_crc *crc = &crtc->crc;
> +	struct drm_crtc_crc_entry *entry;
> +	char buf[MAX_LINE_LEN];
> +	int ret, i;
> +
> +	spin_lock_irq(&crc->lock);
> +
> +	if (!crc->source) {
> +		spin_unlock_irq(&crc->lock);
> +		return 0;
> +	}
> +
> +	/* Nothing to read? */
> +	while (crtc_crc_data_count(crc) == 0) {
> +		if (filep->f_flags & O_NONBLOCK) {
> +			spin_unlock_irq(&crc->lock);
> +			return -EAGAIN;
> +		}
> +
> +		ret = wait_event_interruptible_lock_irq(crc->wq,
> +							crtc_crc_data_count(crc),
> +							crc->lock);
> +		if (ret) {
> +			spin_unlock_irq(&crc->lock);
> +			return ret;
> +		}
> +	}
> +
> +	/* We know we have an entry to be read */
> +	entry = &crc->entries[crc->tail];
> +
> +	if (count < LINE_LEN(crc->values_cnt)) {
> +		spin_unlock_irq(&crc->lock);
> +		return -EINVAL;
> +	}
> +
> +	BUILD_BUG_ON_NOT_POWER_OF_2(DRM_CRC_ENTRIES_NR);
> +	crc->tail = (crc->tail + 1) & (DRM_CRC_ENTRIES_NR - 1);
> +
> +	spin_unlock_irq(&crc->lock);
> +
> +	if (entry->has_frame_counter)
> +		sprintf(buf, "0x%08x", entry->frame);
> +	else
> +		sprintf(buf, "XXXXXXXXXX");
> +
> +	for (i = 0; i < crc->values_cnt; i++)
> +		sprintf(buf + 10 + i * 11, " 0x%08x", entry->crcs[i]);
> +	sprintf(buf + 10 + crc->values_cnt * 11, "\n");
> +
> +	if (copy_to_user(user_buf, buf, LINE_LEN(crc->values_cnt)))
> +		return -EFAULT;
> +
> +	return LINE_LEN(crc->values_cnt);
> +}
> +
> +const struct file_operations drm_crtc_crc_data_fops = {
> +	.owner = THIS_MODULE,
> +	.open = crtc_crc_open,
> +	.read = crtc_crc_read,
> +	.release = crtc_crc_release,
> +};
> +
> +/**
> + * drm_debugfs_crtc_crc_add - Add files to debugfs for capture of frame CRCs
> + * @crtc: CRTC to whom the frames will belong
> + *
> + * Adds files to debugfs directory that allows userspace to control the
> + * generation of frame CRCs and to read them.
> + *
> + * Returns:
> + * Zero on success, error code on failure.
> + */
> +int drm_debugfs_crtc_crc_add(struct drm_crtc *crtc)
> +{
> +	struct dentry *crc_ent, *ent;
> +
> +	if (!crtc->funcs->set_crc_source)
> +		return 0;
> +
> +	crc_ent = debugfs_create_dir("crc", crtc->debugfs_entry);
> +	if (!crc_ent)
> +		return -ENOMEM;
> +
> +	ent = debugfs_create_file("control", S_IRUGO, crc_ent, crtc,
> +				  &drm_crtc_crc_control_fops);
> +	if (!ent)
> +		goto error;
> +
> +	ent = debugfs_create_file("data", S_IRUGO, crc_ent, crtc,
> +				  &drm_crtc_crc_data_fops);
> +	if (!ent)
> +		goto error;
> +
> +	return 0;
> +
> +error:
> +	debugfs_remove_recursive(crc_ent);
> +
> +	return -ENOMEM;
> +}
> +
> +/**
> + * drm_crtc_add_crc_entry - Add entry with CRC information for a frame
> + * @crtc: CRTC to which the frame belongs
> + * @has_frame: whether this entry has a frame number to go with
> + * @frame: number of the frame these CRCs are about
> + * @crcs: array of CRC values, with length matching #drm_crtc_crc.values_cnt
> + *
> + * For each frame, the driver polls the source of CRCs for new data and calls
> + * this function to add them to the buffer from where userspace reads.
> + */
> +int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame,
> +			   uint32_t frame, uint32_t *crcs)
> +{
> +	struct drm_crtc_crc *crc = &crtc->crc;
> +	struct drm_crtc_crc_entry *entry;
> +	int head, tail;
> +
> +	assert_spin_locked(&crc->lock);
> +
> +	/* Caller may not have noticed yet that userspace has stopped reading */
> +	if (!crc->opened)
> +		return -EINVAL;
> +
> +	head = crc->head;
> +	tail = crc->tail;
> +
> +	if (CIRC_SPACE(head, tail, DRM_CRC_ENTRIES_NR) < 1) {
> +		DRM_ERROR("Overflow of CRC buffer, userspace reads too slow.\n");
> +		return -ENOBUFS;
> +	}
> +
> +	entry = &crc->entries[head];
> +	entry->frame = frame;
> +	entry->has_frame_counter = has_frame;
> +	memcpy(&entry->crcs, crcs, sizeof(*crcs) * crc->values_cnt);
> +
> +	head = (head + 1) & (DRM_CRC_ENTRIES_NR - 1);
> +	crc->head = head;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(drm_crtc_add_crc_entry);
> diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h
> index e66af289a016..abd209863ef4 100644
> --- a/drivers/gpu/drm/drm_internal.h
> +++ b/drivers/gpu/drm/drm_internal.h
> @@ -100,6 +100,9 @@ int drm_debugfs_init(struct drm_minor *minor, int minor_id,
>  int drm_debugfs_cleanup(struct drm_minor *minor);
>  int drm_debugfs_connector_add(struct drm_connector *connector);
>  void drm_debugfs_connector_remove(struct drm_connector *connector);
> +int drm_debugfs_crtc_add(struct drm_crtc *crtc);
> +void drm_debugfs_crtc_remove(struct drm_crtc *crtc);
> +int drm_debugfs_crtc_crc_add(struct drm_crtc *crtc);
>  #else
>  static inline int drm_debugfs_init(struct drm_minor *minor, int minor_id,
>  				   struct dentry *root)
> @@ -119,4 +122,17 @@ static inline int drm_debugfs_connector_add(struct drm_connector *connector)
>  static inline void drm_debugfs_connector_remove(struct drm_connector *connector)
>  {
>  }
> +
> +static inline int drm_debugfs_crtc_add(struct drm_crtc *crtc)
> +{
> +	return 0;
> +}
> +static inline void drm_debugfs_crtc_remove(struct drm_crtc *crtc)
> +{
> +}
> +
> +static inline int drm_debugfs_crtc_crc_add(struct drm_crtc *crtc)
> +{
> +	return 0;
> +}
>  #endif
> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> index 61932f55f788..0908b2cf6c2c 100644
> --- a/include/drm/drm_crtc.h
> +++ b/include/drm/drm_crtc.h
> @@ -47,6 +47,7 @@
>  #include <drm/drm_plane.h>
>  #include <drm/drm_blend.h>
>  #include <drm/drm_color_mgmt.h>
> +#include <drm/drm_debugfs_crc.h>
>  
>  struct drm_device;
>  struct drm_mode_set;
> @@ -564,6 +565,30 @@ struct drm_crtc_funcs {
>  	 * before data structures are torndown.
>  	 */
>  	void (*early_unregister)(struct drm_crtc *crtc);
> +
> +	/**
> +	 * @set_crc_source:
> +	 *
> +	 * Changes the source of CRC checksums of frames at the request of
> +	 * userspace, typically for testing purposes. The sources available are
> +	 * specific of each driver and a %NULL value indicates that CRC
> +	 * generation is to be switched off.
> +	 *
> +	 * When CRC generation is enabled, the driver should call
> +	 * drm_crtc_add_crc_entry() at each frame, providing any information
> +	 * that characterizes the frame contents in the crcN arguments, as
> +	 * provided from the configured source. Drivers must accept a "auto"
> +	 * source name that will select a default source for this CRTC.
> +	 *
> +	 * This callback is optional if the driver does not support any CRC
> +	 * generation functionality.
> +	 *
> +	 * RETURNS:
> +	 *
> +	 * 0 on success or a negative error code on failure.
> +	 */
> +	int (*set_crc_source)(struct drm_crtc *crtc, const char *source,
> +			      size_t *values_cnt);
>  };
>  
>  /**
> @@ -680,6 +705,22 @@ struct drm_crtc {
>  	 * context.
>  	 */
>  	struct drm_modeset_acquire_ctx *acquire_ctx;
> +
> +#ifdef CONFIG_DEBUG_FS
> +	/**
> +	 * @debugfs_entry:
> +	 *
> +	 * Debugfs directory for this CRTC.
> +	 */
> +	struct dentry *debugfs_entry;
> +
> +	/**
> +	 * @crc:
> +	 *
> +	 * Configuration settings of CRC capture.
> +	 */
> +	struct drm_crtc_crc crc;
> +#endif
>  };
>  
>  /**
> diff --git a/include/drm/drm_debugfs_crc.h b/include/drm/drm_debugfs_crc.h
> new file mode 100644
> index 000000000000..7d63b1d4adb9
> --- /dev/null
> +++ b/include/drm/drm_debugfs_crc.h
> @@ -0,0 +1,73 @@
> +/*
> + * Copyright © 2016 Collabora Ltd.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
> + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
> + * OTHER DEALINGS IN THE SOFTWARE.
> + */
> +#ifndef __DRM_DEBUGFS_CRC_H__
> +#define __DRM_DEBUGFS_CRC_H__
> +
> +#define DRM_MAX_CRC_NR		10
> +
> +/**
> + * struct drm_crtc_crc_entry - entry describing a frame's content
> + * @has_frame_counter: whether the source was able to provide a frame number
> + * @frame: number of the frame this CRC is about, if @has_frame_counter is true
> + * @crc: array of values that characterize the frame
> + */
> +struct drm_crtc_crc_entry {
> +	bool has_frame_counter;
> +	uint32_t frame;
> +	uint32_t crcs[DRM_MAX_CRC_NR];
> +};
> +
> +#define DRM_CRC_ENTRIES_NR	128
> +
> +/**
> + * struct drm_crtc_crc - data supporting CRC capture on a given CRTC
> + * @lock: protects the fields in this struct
> + * @source: name of the currently configured source of CRCs
> + * @opened: whether userspace has opened the data file for reading
> + * @entries: array of entries, with size of %DRM_CRC_ENTRIES_NR
> + * @head: head of circular queue
> + * @tail: tail of circular queue
> + * @values_cnt: number of CRC values per entry, up to %DRM_MAX_CRC_NR
> + * @wq: workqueue used to synchronize reading and writing
> + */
> +struct drm_crtc_crc {
> +	spinlock_t lock;
> +	const char *source;
> +	bool opened;
> +	struct drm_crtc_crc_entry *entries;
> +	int head, tail;
> +	size_t values_cnt;
> +	wait_queue_head_t wq;
> +};
> +
> +#if defined(CONFIG_DEBUG_FS)
> +int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame,
> +			   uint32_t frame, uint32_t *crcs);
> +#else
> +static inline int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame,
> +					 uint32_t frame, uint32_t *crcs)
> +{
> +	return -EINVAL;
> +}
> +#endif /* defined(CONFIG_DEBUG_FS) */
> +
> +#endif /* __DRM_DEBUGFS_CRC_H__ */
> -- 
> 2.7.4
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

[PATCH v11 3/4] drm/i915: Use new CRC debugfs API

[Tomeu Vizoso]

The core provides now an ABI to userspace for generation of frame CRCs,
so implement the ->set_crc_source() callback and reuse as much code as
possible with the previous ABI implementation.

When handling the pageflip interrupt, we skip 1 or 2 frames depending on
the HW because they contain wrong values. For the legacy ABI for
generating frame CRCs, this was done in userspace but now that we have a
generic ABI it's better if it's not exposed by the kernel.

v2:
    - Leave the legacy implementation in place as the ABI implementation
      in the core is incompatible with it.
v3:
    - Use the "cooked" vblank counter so we have a whole 32 bits.
    - Make sure we don't mess with the state of the legacy CRC capture
      ABI implementation.
v4:
    - Keep use of get_vblank_counter as in the legacy code, will be
      changed in a followup commit.

v5:
    - Skip first frame or two as it's known that they contain wrong
      data.
    - A few fixes suggested by Emil Velikov.

v6:
    - Rework programming of the HW registers to preserve previous
      behavior.

v7:
    - Address whitespace issue.
    - Added a comment on why in the implementation of the new ABI we
      skip the 1st or 2nd frames.

v9:
    - Add stub for intel_crtc_set_crc_source.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
---

 drivers/gpu/drm/i915/i915_drv.h       |  1 +
 drivers/gpu/drm/i915/i915_irq.c       | 83 +++++++++++++++++++++----------
 drivers/gpu/drm/i915/intel_display.c  |  1 +
 drivers/gpu/drm/i915/intel_drv.h      |  8 +++
 drivers/gpu/drm/i915/intel_pipe_crc.c | 94 ++++++++++++++++++++++++++++++-----
 5 files changed, 149 insertions(+), 38 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index f8c66eea06bc..20522f0a4c57 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1713,6 +1713,7 @@ struct intel_pipe_crc {
 	enum intel_pipe_crc_source source;
 	int head, tail;
 	wait_queue_head_t wq;
+	int skipped;
 };
 
 struct i915_frontbuffer_tracking {
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index bd6c8b0eeaef..1549cc4f88ec 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1491,41 +1491,72 @@ static void display_pipe_crc_irq_handler(struct drm_i915_private *dev_priv,
 {
 	struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[pipe];
 	struct intel_pipe_crc_entry *entry;
-	int head, tail;
+	struct drm_crtc *crtc = intel_get_crtc_for_pipe(&dev_priv->drm, pipe);
+	struct drm_driver *driver = dev_priv->drm.driver;
+	uint32_t crcs[5];
+	int head, tail, ret;
+	u32 frame;
 
 	spin_lock(&pipe_crc->lock);
+	if (pipe_crc->source) {
+		if (!pipe_crc->entries) {
+			spin_unlock(&pipe_crc->lock);
+			DRM_DEBUG_KMS("spurious interrupt\n");
+			return;
+		}
 
-	if (!pipe_crc->entries) {
-		spin_unlock(&pipe_crc->lock);
-		DRM_DEBUG_KMS("spurious interrupt\n");
-		return;
-	}
-
-	head = pipe_crc->head;
-	tail = pipe_crc->tail;
+		head = pipe_crc->head;
+		tail = pipe_crc->tail;
 
-	if (CIRC_SPACE(head, tail, INTEL_PIPE_CRC_ENTRIES_NR) < 1) {
-		spin_unlock(&pipe_crc->lock);
-		DRM_ERROR("CRC buffer overflowing\n");
-		return;
-	}
+		if (CIRC_SPACE(head, tail, INTEL_PIPE_CRC_ENTRIES_NR) < 1) {
+			spin_unlock(&pipe_crc->lock);
+			DRM_ERROR("CRC buffer overflowing\n");
+			return;
+		}
 
-	entry = &pipe_crc->entries[head];
+		entry = &pipe_crc->entries[head];
 
-	entry->frame = dev_priv->drm.driver->get_vblank_counter(&dev_priv->drm,
-								 pipe);
-	entry->crc[0] = crc0;
-	entry->crc[1] = crc1;
-	entry->crc[2] = crc2;
-	entry->crc[3] = crc3;
-	entry->crc[4] = crc4;
+		entry->frame = driver->get_vblank_counter(&dev_priv->drm, pipe);
+		entry->crc[0] = crc0;
+		entry->crc[1] = crc1;
+		entry->crc[2] = crc2;
+		entry->crc[3] = crc3;
+		entry->crc[4] = crc4;
 
-	head = (head + 1) & (INTEL_PIPE_CRC_ENTRIES_NR - 1);
-	pipe_crc->head = head;
+		head = (head + 1) & (INTEL_PIPE_CRC_ENTRIES_NR - 1);
+		pipe_crc->head = head;
 
-	spin_unlock(&pipe_crc->lock);
+		spin_unlock(&pipe_crc->lock);
 
-	wake_up_interruptible(&pipe_crc->wq);
+		wake_up_interruptible(&pipe_crc->wq);
+	} else {
+		/*
+		 * For some not yet identified reason, the first CRC is
+		 * bonkers. So let's just wait for the next vblank and read
+		 * out the buggy result.
+		 *
+		 * On CHV sometimes the second CRC is bonkers as well, so
+		 * don't trust that one either.
+		 */
+		if (pipe_crc->skipped == 0 ||
+		    (IS_CHERRYVIEW(dev_priv) && pipe_crc->skipped == 1)) {
+			pipe_crc->skipped++;
+			spin_unlock(&pipe_crc->lock);
+			return;
+		}
+		spin_unlock(&pipe_crc->lock);
+		spin_lock(&crtc->crc.lock);
+		crcs[0] = crc0;
+		crcs[1] = crc1;
+		crcs[2] = crc2;
+		crcs[3] = crc3;
+		crcs[4] = crc4;
+		frame = driver->get_vblank_counter(&dev_priv->drm, pipe);
+		ret = drm_crtc_add_crc_entry(crtc, true, frame, crcs);
+		spin_unlock(&crtc->crc.lock);
+		if (!ret)
+			wake_up_interruptible(&crtc->crc.wq);
+	}
 }
 #else
 static inline void
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 23a6c7213eca..7412a05fa5d9 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -14636,6 +14636,7 @@ static const struct drm_crtc_funcs intel_crtc_funcs = {
 	.page_flip = intel_crtc_page_flip,
 	.atomic_duplicate_state = intel_crtc_duplicate_state,
 	.atomic_destroy_state = intel_crtc_destroy_state,
+	.set_crc_source = intel_crtc_set_crc_source,
 };
 
 /**
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 737261b09110..31894b7c6517 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1844,6 +1844,14 @@ void intel_color_load_luts(struct drm_crtc_state *crtc_state);
 /* intel_pipe_crc.c */
 int intel_pipe_crc_create(struct drm_minor *minor);
 void intel_pipe_crc_cleanup(struct drm_minor *minor);
+#ifdef CONFIG_DEBUG_FS
+int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name,
+			      size_t *values_cnt);
+#else
+static inline int intel_crtc_set_crc_source(struct drm_crtc *crtc,
+					    const char *source_name,
+					    size_t *values_cnt) { return 0; }
+#endif
 extern const struct file_operations i915_display_crc_ctl_fops;
 
 #endif /* __INTEL_DRV_H__ */
diff --git a/drivers/gpu/drm/i915/intel_pipe_crc.c b/drivers/gpu/drm/i915/intel_pipe_crc.c
index 6c38d4fdcaef..1a51e174e9e5 100644
--- a/drivers/gpu/drm/i915/intel_pipe_crc.c
+++ b/drivers/gpu/drm/i915/intel_pipe_crc.c
@@ -615,6 +615,22 @@ static int ivb_pipe_crc_ctl_reg(struct drm_i915_private *dev_priv,
 	return 0;
 }
 
+static int get_new_crc_ctl_reg(struct drm_i915_private *dev_priv,
+			       enum pipe pipe,
+			       enum intel_pipe_crc_source *source, u32 *val)
+{
+	if (IS_GEN2(dev_priv))
+		return i8xx_pipe_crc_ctl_reg(source, val);
+	else if (INTEL_GEN(dev_priv) < 5)
+		return i9xx_pipe_crc_ctl_reg(dev_priv, pipe, source, val);
+	else if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
+		return vlv_pipe_crc_ctl_reg(dev_priv, pipe, source, val);
+	else if (IS_GEN5(dev_priv) || IS_GEN6(dev_priv))
+		return ilk_pipe_crc_ctl_reg(source, val);
+	else
+		return ivb_pipe_crc_ctl_reg(dev_priv, pipe, source, val);
+}
+
 static int pipe_crc_set_source(struct drm_i915_private *dev_priv,
 			       enum pipe pipe,
 			       enum intel_pipe_crc_source source)
@@ -640,17 +656,7 @@ static int pipe_crc_set_source(struct drm_i915_private *dev_priv,
 		return -EIO;
 	}
 
-	if (IS_GEN2(dev_priv))
-		ret = i8xx_pipe_crc_ctl_reg(&source, &val);
-	else if (INTEL_GEN(dev_priv) < 5)
-		ret = i9xx_pipe_crc_ctl_reg(dev_priv, pipe, &source, &val);
-	else if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
-		ret = vlv_pipe_crc_ctl_reg(dev_priv, pipe, &source, &val);
-	else if (IS_GEN5(dev_priv) || IS_GEN6(dev_priv))
-		ret = ilk_pipe_crc_ctl_reg(&source, &val);
-	else
-		ret = ivb_pipe_crc_ctl_reg(dev_priv, pipe, &source, &val);
-
+	ret = get_new_crc_ctl_reg(dev_priv, pipe, &source, &val);
 	if (ret != 0)
 		goto out;
 
@@ -691,7 +697,7 @@ static int pipe_crc_set_source(struct drm_i915_private *dev_priv,
 	POSTING_READ(PIPE_CRC_CTL(pipe));
 
 	/* real source -> none transition */
-	if (source == INTEL_PIPE_CRC_SOURCE_NONE) {
+	if (!source) {
 		struct intel_pipe_crc_entry *entries;
 		struct intel_crtc *crtc =
 			to_intel_crtc(dev_priv->pipe_to_crtc_mapping[pipe]);
@@ -813,6 +819,11 @@ display_crc_ctl_parse_source(const char *buf, enum intel_pipe_crc_source *s)
 {
 	int i;
 
+	if (!buf) {
+		*s = INTEL_PIPE_CRC_SOURCE_NONE;
+		return 0;
+	}
+
 	for (i = 0; i < ARRAY_SIZE(pipe_crc_sources); i++)
 		if (!strcmp(buf, pipe_crc_sources[i])) {
 			*s = i;
@@ -941,3 +952,62 @@ void intel_pipe_crc_cleanup(struct drm_minor *minor)
 		drm_debugfs_remove_files(info_list, 1, minor);
 	}
 }
+
+int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name,
+			      size_t *values_cnt)
+{
+	struct drm_i915_private *dev_priv = crtc->dev->dev_private;
+	struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[crtc->index];
+	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+	enum intel_display_power_domain power_domain;
+	enum intel_pipe_crc_source source;
+	u32 val = 0; /* shut up gcc */
+	int ret = 0;
+
+	if (display_crc_ctl_parse_source(source_name, &source) < 0) {
+		DRM_DEBUG_DRIVER("unknown source %s\n", source_name);
+		return -EINVAL;
+	}
+
+	power_domain = POWER_DOMAIN_PIPE(crtc->index);
+	if (!intel_display_power_get_if_enabled(dev_priv, power_domain)) {
+		DRM_DEBUG_KMS("Trying to capture CRC while pipe is off\n");
+		return -EIO;
+	}
+
+	ret = get_new_crc_ctl_reg(dev_priv, crtc->index, &source, &val);
+	if (ret != 0)
+		goto out;
+
+	if (source) {
+		/*
+		 * When IPS gets enabled, the pipe CRC changes. Since IPS gets
+		 * enabled and disabled dynamically based on package C states,
+		 * user space can't make reliable use of the CRCs, so let's just
+		 * completely disable it.
+		 */
+		hsw_disable_ips(intel_crtc);
+	}
+
+	I915_WRITE(PIPE_CRC_CTL(crtc->index), val);
+	POSTING_READ(PIPE_CRC_CTL(crtc->index));
+
+	if (!source) {
+		if (IS_G4X(dev_priv))
+			g4x_undo_pipe_scramble_reset(dev_priv, crtc->index);
+		else if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
+			vlv_undo_pipe_scramble_reset(dev_priv, crtc->index);
+		else if (IS_HASWELL(dev_priv) && crtc->index == PIPE_A)
+			hsw_trans_edp_pipe_A_crc_wa(dev_priv, false);
+
+		hsw_enable_ips(intel_crtc);
+	}
+
+	pipe_crc->skipped = 0;
+	*values_cnt = 5;
+
+out:
+	intel_display_power_put(dev_priv, power_domain);
+
+	return ret;
+}
-- 
2.7.4

Re: [PATCH v11 3/4] drm/i915: Use new CRC debugfs API

[Jani Nikula]

On Thu, 06 Oct 2016, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote:
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 23a6c7213eca..7412a05fa5d9 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -14636,6 +14636,7 @@ static const struct drm_crtc_funcs intel_crtc_funcs = {
>  	.page_flip = intel_crtc_page_flip,
>  	.atomic_duplicate_state = intel_crtc_duplicate_state,
>  	.atomic_destroy_state = intel_crtc_destroy_state,
> +	.set_crc_source = intel_crtc_set_crc_source,
>  };
>  
>  /**
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 737261b09110..31894b7c6517 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1844,6 +1844,14 @@ void intel_color_load_luts(struct drm_crtc_state *crtc_state);
>  /* intel_pipe_crc.c */
>  int intel_pipe_crc_create(struct drm_minor *minor);
>  void intel_pipe_crc_cleanup(struct drm_minor *minor);
> +#ifdef CONFIG_DEBUG_FS
> +int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name,
> +			      size_t *values_cnt);
> +#else
> +static inline int intel_crtc_set_crc_source(struct drm_crtc *crtc,
> +					    const char *source_name,
> +					    size_t *values_cnt) { return 0; }
> +#endif

"inline" here doesn't work because it's used as a function pointer.

Is it better to have a function that returns 0 for .set_crc_source, or
to set .set_crc_source to NULL when CONFIG_DEBUG_FS=n?

BR,
Jani.


>  extern const struct file_operations i915_display_crc_ctl_fops;
>  
>  #endif /* __INTEL_DRV_H__ */
> diff --git a/drivers/gpu/drm/i915/intel_pipe_crc.c b/drivers/gpu/drm/i915/intel_pipe_crc.c
> index 6c38d4fdcaef..1a51e174e9e5 100644
> --- a/drivers/gpu/drm/i915/intel_pipe_crc.c
> +++ b/drivers/gpu/drm/i915/intel_pipe_crc.c
> @@ -615,6 +615,22 @@ static int ivb_pipe_crc_ctl_reg(struct drm_i915_private *dev_priv,
>  	return 0;
>  }
>  
> +static int get_new_crc_ctl_reg(struct drm_i915_private *dev_priv,
> +			       enum pipe pipe,
> +			       enum intel_pipe_crc_source *source, u32 *val)
> +{
> +	if (IS_GEN2(dev_priv))
> +		return i8xx_pipe_crc_ctl_reg(source, val);
> +	else if (INTEL_GEN(dev_priv) < 5)
> +		return i9xx_pipe_crc_ctl_reg(dev_priv, pipe, source, val);
> +	else if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
> +		return vlv_pipe_crc_ctl_reg(dev_priv, pipe, source, val);
> +	else if (IS_GEN5(dev_priv) || IS_GEN6(dev_priv))
> +		return ilk_pipe_crc_ctl_reg(source, val);
> +	else
> +		return ivb_pipe_crc_ctl_reg(dev_priv, pipe, source, val);
> +}
> +
>  static int pipe_crc_set_source(struct drm_i915_private *dev_priv,
>  			       enum pipe pipe,
>  			       enum intel_pipe_crc_source source)
> @@ -640,17 +656,7 @@ static int pipe_crc_set_source(struct drm_i915_private *dev_priv,
>  		return -EIO;
>  	}
>  
> -	if (IS_GEN2(dev_priv))
> -		ret = i8xx_pipe_crc_ctl_reg(&source, &val);
> -	else if (INTEL_GEN(dev_priv) < 5)
> -		ret = i9xx_pipe_crc_ctl_reg(dev_priv, pipe, &source, &val);
> -	else if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
> -		ret = vlv_pipe_crc_ctl_reg(dev_priv, pipe, &source, &val);
> -	else if (IS_GEN5(dev_priv) || IS_GEN6(dev_priv))
> -		ret = ilk_pipe_crc_ctl_reg(&source, &val);
> -	else
> -		ret = ivb_pipe_crc_ctl_reg(dev_priv, pipe, &source, &val);
> -
> +	ret = get_new_crc_ctl_reg(dev_priv, pipe, &source, &val);
>  	if (ret != 0)
>  		goto out;
>  
> @@ -691,7 +697,7 @@ static int pipe_crc_set_source(struct drm_i915_private *dev_priv,
>  	POSTING_READ(PIPE_CRC_CTL(pipe));
>  
>  	/* real source -> none transition */
> -	if (source == INTEL_PIPE_CRC_SOURCE_NONE) {
> +	if (!source) {
>  		struct intel_pipe_crc_entry *entries;
>  		struct intel_crtc *crtc =
>  			to_intel_crtc(dev_priv->pipe_to_crtc_mapping[pipe]);
> @@ -813,6 +819,11 @@ display_crc_ctl_parse_source(const char *buf, enum intel_pipe_crc_source *s)
>  {
>  	int i;
>  
> +	if (!buf) {
> +		*s = INTEL_PIPE_CRC_SOURCE_NONE;
> +		return 0;
> +	}
> +
>  	for (i = 0; i < ARRAY_SIZE(pipe_crc_sources); i++)
>  		if (!strcmp(buf, pipe_crc_sources[i])) {
>  			*s = i;
> @@ -941,3 +952,62 @@ void intel_pipe_crc_cleanup(struct drm_minor *minor)
>  		drm_debugfs_remove_files(info_list, 1, minor);
>  	}
>  }
> +
> +int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name,
> +			      size_t *values_cnt)
> +{
> +	struct drm_i915_private *dev_priv = crtc->dev->dev_private;
> +	struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[crtc->index];
> +	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> +	enum intel_display_power_domain power_domain;
> +	enum intel_pipe_crc_source source;
> +	u32 val = 0; /* shut up gcc */
> +	int ret = 0;
> +
> +	if (display_crc_ctl_parse_source(source_name, &source) < 0) {
> +		DRM_DEBUG_DRIVER("unknown source %s\n", source_name);
> +		return -EINVAL;
> +	}
> +
> +	power_domain = POWER_DOMAIN_PIPE(crtc->index);
> +	if (!intel_display_power_get_if_enabled(dev_priv, power_domain)) {
> +		DRM_DEBUG_KMS("Trying to capture CRC while pipe is off\n");
> +		return -EIO;
> +	}
> +
> +	ret = get_new_crc_ctl_reg(dev_priv, crtc->index, &source, &val);
> +	if (ret != 0)
> +		goto out;
> +
> +	if (source) {
> +		/*
> +		 * When IPS gets enabled, the pipe CRC changes. Since IPS gets
> +		 * enabled and disabled dynamically based on package C states,
> +		 * user space can't make reliable use of the CRCs, so let's just
> +		 * completely disable it.
> +		 */
> +		hsw_disable_ips(intel_crtc);
> +	}
> +
> +	I915_WRITE(PIPE_CRC_CTL(crtc->index), val);
> +	POSTING_READ(PIPE_CRC_CTL(crtc->index));
> +
> +	if (!source) {
> +		if (IS_G4X(dev_priv))
> +			g4x_undo_pipe_scramble_reset(dev_priv, crtc->index);
> +		else if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
> +			vlv_undo_pipe_scramble_reset(dev_priv, crtc->index);
> +		else if (IS_HASWELL(dev_priv) && crtc->index == PIPE_A)
> +			hsw_trans_edp_pipe_A_crc_wa(dev_priv, false);
> +
> +		hsw_enable_ips(intel_crtc);
> +	}
> +
> +	pipe_crc->skipped = 0;
> +	*values_cnt = 5;
> +
> +out:
> +	intel_display_power_put(dev_priv, power_domain);
> +
> +	return ret;
> +}

-- 
Jani Nikula, Intel Open Source Technology Center

Re: [Intel-gfx] [PATCH v11 3/4] drm/i915: Use new CRC debugfs API

[David Weinehall]

On Mon, Nov 14, 2016 at 12:44:25PM +0200, Jani Nikula wrote:
> On Thu, 06 Oct 2016, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote:
> > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> > index 23a6c7213eca..7412a05fa5d9 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -14636,6 +14636,7 @@ static const struct drm_crtc_funcs intel_crtc_funcs = {
> >  	.page_flip = intel_crtc_page_flip,
> >  	.atomic_duplicate_state = intel_crtc_duplicate_state,
> >  	.atomic_destroy_state = intel_crtc_destroy_state,
> > +	.set_crc_source = intel_crtc_set_crc_source,
> >  };
> >  
> >  /**
> > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> > index 737261b09110..31894b7c6517 100644
> > --- a/drivers/gpu/drm/i915/intel_drv.h
> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > @@ -1844,6 +1844,14 @@ void intel_color_load_luts(struct drm_crtc_state *crtc_state);
> >  /* intel_pipe_crc.c */
> >  int intel_pipe_crc_create(struct drm_minor *minor);
> >  void intel_pipe_crc_cleanup(struct drm_minor *minor);
> > +#ifdef CONFIG_DEBUG_FS
> > +int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name,
> > +			      size_t *values_cnt);
> > +#else
> > +static inline int intel_crtc_set_crc_source(struct drm_crtc *crtc,
> > +					    const char *source_name,
> > +					    size_t *values_cnt) { return 0; }
> > +#endif
> 
> "inline" here doesn't work because it's used as a function pointer.
> 
> Is it better to have a function that returns 0 for .set_crc_source, or
> to set .set_crc_source to NULL when CONFIG_DEBUG_FS=n?

I'd say that whenever we have a function pointer we should have a dummy
function without side-effects for this kind of things.


Kind regards, David

Re: [Intel-gfx] [PATCH v11 3/4] drm/i915: Use new CRC debugfs API

[Jani Nikula]

On Tue, 15 Nov 2016, David Weinehall <tao@kernel.org> wrote:
> On Mon, Nov 14, 2016 at 12:44:25PM +0200, Jani Nikula wrote:
>> On Thu, 06 Oct 2016, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote:
>> > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
>> > index 23a6c7213eca..7412a05fa5d9 100644
>> > --- a/drivers/gpu/drm/i915/intel_display.c
>> > +++ b/drivers/gpu/drm/i915/intel_display.c
>> > @@ -14636,6 +14636,7 @@ static const struct drm_crtc_funcs intel_crtc_funcs = {
>> >  	.page_flip = intel_crtc_page_flip,
>> >  	.atomic_duplicate_state = intel_crtc_duplicate_state,
>> >  	.atomic_destroy_state = intel_crtc_destroy_state,
>> > +	.set_crc_source = intel_crtc_set_crc_source,
>> >  };
>> >  
>> >  /**
>> > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>> > index 737261b09110..31894b7c6517 100644
>> > --- a/drivers/gpu/drm/i915/intel_drv.h
>> > +++ b/drivers/gpu/drm/i915/intel_drv.h
>> > @@ -1844,6 +1844,14 @@ void intel_color_load_luts(struct drm_crtc_state *crtc_state);
>> >  /* intel_pipe_crc.c */
>> >  int intel_pipe_crc_create(struct drm_minor *minor);
>> >  void intel_pipe_crc_cleanup(struct drm_minor *minor);
>> > +#ifdef CONFIG_DEBUG_FS
>> > +int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name,
>> > +			      size_t *values_cnt);
>> > +#else
>> > +static inline int intel_crtc_set_crc_source(struct drm_crtc *crtc,
>> > +					    const char *source_name,
>> > +					    size_t *values_cnt) { return 0; }
>> > +#endif
>> 
>> "inline" here doesn't work because it's used as a function pointer.
>> 
>> Is it better to have a function that returns 0 for .set_crc_source, or
>> to set .set_crc_source to NULL when CONFIG_DEBUG_FS=n?
>
> I'd say that whenever we have a function pointer we should have a dummy
> function without side-effects for this kind of things.

Whoever calls .set_crc_source could do smarter things depending on the
hook not being there vs. just silently plunging on.

BR,
Jani.


>
>
> Kind regards, David

-- 
Jani Nikula, Intel Open Source Technology Center

Re: [Intel-gfx] [PATCH v11 3/4] drm/i915: Use new CRC debugfs API

[Tomeu Vizoso]

On 15 November 2016 at 09:27, Jani Nikula <jani.nikula@linux.intel.com> wrote:
> On Tue, 15 Nov 2016, David Weinehall <tao@kernel.org> wrote:
>> On Mon, Nov 14, 2016 at 12:44:25PM +0200, Jani Nikula wrote:
>>> On Thu, 06 Oct 2016, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote:
>>> > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
>>> > index 23a6c7213eca..7412a05fa5d9 100644
>>> > --- a/drivers/gpu/drm/i915/intel_display.c
>>> > +++ b/drivers/gpu/drm/i915/intel_display.c
>>> > @@ -14636,6 +14636,7 @@ static const struct drm_crtc_funcs intel_crtc_funcs = {
>>> >    .page_flip = intel_crtc_page_flip,
>>> >    .atomic_duplicate_state = intel_crtc_duplicate_state,
>>> >    .atomic_destroy_state = intel_crtc_destroy_state,
>>> > +  .set_crc_source = intel_crtc_set_crc_source,
>>> >  };
>>> >
>>> >  /**
>>> > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>>> > index 737261b09110..31894b7c6517 100644
>>> > --- a/drivers/gpu/drm/i915/intel_drv.h
>>> > +++ b/drivers/gpu/drm/i915/intel_drv.h
>>> > @@ -1844,6 +1844,14 @@ void intel_color_load_luts(struct drm_crtc_state *crtc_state);
>>> >  /* intel_pipe_crc.c */
>>> >  int intel_pipe_crc_create(struct drm_minor *minor);
>>> >  void intel_pipe_crc_cleanup(struct drm_minor *minor);
>>> > +#ifdef CONFIG_DEBUG_FS
>>> > +int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name,
>>> > +                        size_t *values_cnt);
>>> > +#else
>>> > +static inline int intel_crtc_set_crc_source(struct drm_crtc *crtc,
>>> > +                                      const char *source_name,
>>> > +                                      size_t *values_cnt) { return 0; }
>>> > +#endif
>>>
>>> "inline" here doesn't work because it's used as a function pointer.
>>>
>>> Is it better to have a function that returns 0 for .set_crc_source, or
>>> to set .set_crc_source to NULL when CONFIG_DEBUG_FS=n?
>>
>> I'd say that whenever we have a function pointer we should have a dummy
>> function without side-effects for this kind of things.
>
> Whoever calls .set_crc_source could do smarter things depending on the
> hook not being there vs. just silently plunging on.

In this specific case, when CONFIG_DEBUG_FS=n it doesn't make any
sense to call that callback, so I think we should have a dummy
implementation to avoid adding an ifdef to the .c.

Regards,

Tomeu

Re: [Intel-gfx] [PATCH v11 3/4] drm/i915: Use new CRC debugfs API

[Jani Nikula]

On Wed, 16 Nov 2016, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote:
> On 15 November 2016 at 09:27, Jani Nikula <jani.nikula@linux.intel.com> wrote:
>> On Tue, 15 Nov 2016, David Weinehall <tao@kernel.org> wrote:
>>> On Mon, Nov 14, 2016 at 12:44:25PM +0200, Jani Nikula wrote:
>>>> On Thu, 06 Oct 2016, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote:
>>>> > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
>>>> > index 23a6c7213eca..7412a05fa5d9 100644
>>>> > --- a/drivers/gpu/drm/i915/intel_display.c
>>>> > +++ b/drivers/gpu/drm/i915/intel_display.c
>>>> > @@ -14636,6 +14636,7 @@ static const struct drm_crtc_funcs intel_crtc_funcs = {
>>>> >    .page_flip = intel_crtc_page_flip,
>>>> >    .atomic_duplicate_state = intel_crtc_duplicate_state,
>>>> >    .atomic_destroy_state = intel_crtc_destroy_state,
>>>> > +  .set_crc_source = intel_crtc_set_crc_source,
>>>> >  };
>>>> >
>>>> >  /**
>>>> > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>>>> > index 737261b09110..31894b7c6517 100644
>>>> > --- a/drivers/gpu/drm/i915/intel_drv.h
>>>> > +++ b/drivers/gpu/drm/i915/intel_drv.h
>>>> > @@ -1844,6 +1844,14 @@ void intel_color_load_luts(struct drm_crtc_state *crtc_state);
>>>> >  /* intel_pipe_crc.c */
>>>> >  int intel_pipe_crc_create(struct drm_minor *minor);
>>>> >  void intel_pipe_crc_cleanup(struct drm_minor *minor);
>>>> > +#ifdef CONFIG_DEBUG_FS
>>>> > +int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name,
>>>> > +                        size_t *values_cnt);
>>>> > +#else
>>>> > +static inline int intel_crtc_set_crc_source(struct drm_crtc *crtc,
>>>> > +                                      const char *source_name,
>>>> > +                                      size_t *values_cnt) { return 0; }
>>>> > +#endif
>>>>
>>>> "inline" here doesn't work because it's used as a function pointer.
>>>>
>>>> Is it better to have a function that returns 0 for .set_crc_source, or
>>>> to set .set_crc_source to NULL when CONFIG_DEBUG_FS=n?
>>>
>>> I'd say that whenever we have a function pointer we should have a dummy
>>> function without side-effects for this kind of things.
>>
>> Whoever calls .set_crc_source could do smarter things depending on the
>> hook not being there vs. just silently plunging on.
>
> In this specific case, when CONFIG_DEBUG_FS=n it doesn't make any
> sense to call that callback, so I think we should have a dummy
> implementation to avoid adding an ifdef to the .c.

We don't want the ifdef to the .c file, but we could do

#ifdef CONFIG_DEBUG_FS
int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name,
				size_t *values_cnt);
#else
#define intel_crtc_set_crc_source NULL
#endif

BR,
Jani.

-- 
Jani Nikula, Intel Open Source Technology Center

Re: [Intel-gfx] [PATCH v11 3/4] drm/i915: Use new CRC debugfs API

[Tomeu Vizoso]

On 16 November 2016 at 13:58, Jani Nikula <jani.nikula@linux.intel.com> wrote:
> On Wed, 16 Nov 2016, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote:
>> On 15 November 2016 at 09:27, Jani Nikula <jani.nikula@linux.intel.com> wrote:
>>> On Tue, 15 Nov 2016, David Weinehall <tao@kernel.org> wrote:
>>>> On Mon, Nov 14, 2016 at 12:44:25PM +0200, Jani Nikula wrote:
>>>>> On Thu, 06 Oct 2016, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote:
>>>>> > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
>>>>> > index 23a6c7213eca..7412a05fa5d9 100644
>>>>> > --- a/drivers/gpu/drm/i915/intel_display.c
>>>>> > +++ b/drivers/gpu/drm/i915/intel_display.c
>>>>> > @@ -14636,6 +14636,7 @@ static const struct drm_crtc_funcs intel_crtc_funcs = {
>>>>> >    .page_flip = intel_crtc_page_flip,
>>>>> >    .atomic_duplicate_state = intel_crtc_duplicate_state,
>>>>> >    .atomic_destroy_state = intel_crtc_destroy_state,
>>>>> > +  .set_crc_source = intel_crtc_set_crc_source,
>>>>> >  };
>>>>> >
>>>>> >  /**
>>>>> > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>>>>> > index 737261b09110..31894b7c6517 100644
>>>>> > --- a/drivers/gpu/drm/i915/intel_drv.h
>>>>> > +++ b/drivers/gpu/drm/i915/intel_drv.h
>>>>> > @@ -1844,6 +1844,14 @@ void intel_color_load_luts(struct drm_crtc_state *crtc_state);
>>>>> >  /* intel_pipe_crc.c */
>>>>> >  int intel_pipe_crc_create(struct drm_minor *minor);
>>>>> >  void intel_pipe_crc_cleanup(struct drm_minor *minor);
>>>>> > +#ifdef CONFIG_DEBUG_FS
>>>>> > +int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name,
>>>>> > +                        size_t *values_cnt);
>>>>> > +#else
>>>>> > +static inline int intel_crtc_set_crc_source(struct drm_crtc *crtc,
>>>>> > +                                      const char *source_name,
>>>>> > +                                      size_t *values_cnt) { return 0; }
>>>>> > +#endif
>>>>>
>>>>> "inline" here doesn't work because it's used as a function pointer.
>>>>>
>>>>> Is it better to have a function that returns 0 for .set_crc_source, or
>>>>> to set .set_crc_source to NULL when CONFIG_DEBUG_FS=n?
>>>>
>>>> I'd say that whenever we have a function pointer we should have a dummy
>>>> function without side-effects for this kind of things.
>>>
>>> Whoever calls .set_crc_source could do smarter things depending on the
>>> hook not being there vs. just silently plunging on.
>>
>> In this specific case, when CONFIG_DEBUG_FS=n it doesn't make any
>> sense to call that callback, so I think we should have a dummy
>> implementation to avoid adding an ifdef to the .c.
>
> We don't want the ifdef to the .c file, but we could do
>
> #ifdef CONFIG_DEBUG_FS
> int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name,
>                                 size_t *values_cnt);
> #else
> #define intel_crtc_set_crc_source NULL
> #endif

Sounds good to me, and though I don't have any objections, wonder why
this isn't a common idiom in the DRM subsystem. I was able to find
only one instance: drm_compat_ioctl.

Regards,

Tomeu

Re: [Intel-gfx] [PATCH v11 3/4] drm/i915: Use new CRC debugfs API

[Jani Nikula]

On Wed, 16 Nov 2016, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote:
> On 16 November 2016 at 13:58, Jani Nikula <jani.nikula@linux.intel.com> wrote:
>> On Wed, 16 Nov 2016, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote:
>>> On 15 November 2016 at 09:27, Jani Nikula <jani.nikula@linux.intel.com> wrote:
>>>> On Tue, 15 Nov 2016, David Weinehall <tao@kernel.org> wrote:
>>>>> On Mon, Nov 14, 2016 at 12:44:25PM +0200, Jani Nikula wrote:
>>>>>> On Thu, 06 Oct 2016, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote:
>>>>>> > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
>>>>>> > index 23a6c7213eca..7412a05fa5d9 100644
>>>>>> > --- a/drivers/gpu/drm/i915/intel_display.c
>>>>>> > +++ b/drivers/gpu/drm/i915/intel_display.c
>>>>>> > @@ -14636,6 +14636,7 @@ static const struct drm_crtc_funcs intel_crtc_funcs = {
>>>>>> >    .page_flip = intel_crtc_page_flip,
>>>>>> >    .atomic_duplicate_state = intel_crtc_duplicate_state,
>>>>>> >    .atomic_destroy_state = intel_crtc_destroy_state,
>>>>>> > +  .set_crc_source = intel_crtc_set_crc_source,
>>>>>> >  };
>>>>>> >
>>>>>> >  /**
>>>>>> > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>>>>>> > index 737261b09110..31894b7c6517 100644
>>>>>> > --- a/drivers/gpu/drm/i915/intel_drv.h
>>>>>> > +++ b/drivers/gpu/drm/i915/intel_drv.h
>>>>>> > @@ -1844,6 +1844,14 @@ void intel_color_load_luts(struct drm_crtc_state *crtc_state);
>>>>>> >  /* intel_pipe_crc.c */
>>>>>> >  int intel_pipe_crc_create(struct drm_minor *minor);
>>>>>> >  void intel_pipe_crc_cleanup(struct drm_minor *minor);
>>>>>> > +#ifdef CONFIG_DEBUG_FS
>>>>>> > +int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name,
>>>>>> > +                        size_t *values_cnt);
>>>>>> > +#else
>>>>>> > +static inline int intel_crtc_set_crc_source(struct drm_crtc *crtc,
>>>>>> > +                                      const char *source_name,
>>>>>> > +                                      size_t *values_cnt) { return 0; }
>>>>>> > +#endif
>>>>>>
>>>>>> "inline" here doesn't work because it's used as a function pointer.
>>>>>>
>>>>>> Is it better to have a function that returns 0 for .set_crc_source, or
>>>>>> to set .set_crc_source to NULL when CONFIG_DEBUG_FS=n?
>>>>>
>>>>> I'd say that whenever we have a function pointer we should have a dummy
>>>>> function without side-effects for this kind of things.
>>>>
>>>> Whoever calls .set_crc_source could do smarter things depending on the
>>>> hook not being there vs. just silently plunging on.
>>>
>>> In this specific case, when CONFIG_DEBUG_FS=n it doesn't make any
>>> sense to call that callback, so I think we should have a dummy
>>> implementation to avoid adding an ifdef to the .c.
>>
>> We don't want the ifdef to the .c file, but we could do
>>
>> #ifdef CONFIG_DEBUG_FS
>> int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name,
>>                                 size_t *values_cnt);
>> #else
>> #define intel_crtc_set_crc_source NULL
>> #endif
>
> Sounds good to me, and though I don't have any objections, wonder why
> this isn't a common idiom in the DRM subsystem. I was able to find
> only one instance: drm_compat_ioctl.

Heh, and it was I who suggested that too. Maybe get a second opinion. ;)

BR,
Jani.

>
> Regards,
>
> Tomeu

-- 
Jani Nikula, Intel Open Source Technology Center

Re: [Intel-gfx] [PATCH v11 3/4] drm/i915: Use new CRC debugfs API

[Daniel Vetter]

On Wed, Nov 16, 2016 at 04:08:30PM +0200, Jani Nikula wrote:
> On Wed, 16 Nov 2016, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote:
> > On 16 November 2016 at 13:58, Jani Nikula <jani.nikula@linux.intel.com> wrote:
> >> On Wed, 16 Nov 2016, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote:
> >>> On 15 November 2016 at 09:27, Jani Nikula <jani.nikula@linux.intel.com> wrote:
> >>>> On Tue, 15 Nov 2016, David Weinehall <tao@kernel.org> wrote:
> >>>>> On Mon, Nov 14, 2016 at 12:44:25PM +0200, Jani Nikula wrote:
> >>>>>> On Thu, 06 Oct 2016, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote:
> >>>>>> > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> >>>>>> > index 23a6c7213eca..7412a05fa5d9 100644
> >>>>>> > --- a/drivers/gpu/drm/i915/intel_display.c
> >>>>>> > +++ b/drivers/gpu/drm/i915/intel_display.c
> >>>>>> > @@ -14636,6 +14636,7 @@ static const struct drm_crtc_funcs intel_crtc_funcs = {
> >>>>>> >    .page_flip = intel_crtc_page_flip,
> >>>>>> >    .atomic_duplicate_state = intel_crtc_duplicate_state,
> >>>>>> >    .atomic_destroy_state = intel_crtc_destroy_state,
> >>>>>> > +  .set_crc_source = intel_crtc_set_crc_source,
> >>>>>> >  };
> >>>>>> >
> >>>>>> >  /**
> >>>>>> > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> >>>>>> > index 737261b09110..31894b7c6517 100644
> >>>>>> > --- a/drivers/gpu/drm/i915/intel_drv.h
> >>>>>> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> >>>>>> > @@ -1844,6 +1844,14 @@ void intel_color_load_luts(struct drm_crtc_state *crtc_state);
> >>>>>> >  /* intel_pipe_crc.c */
> >>>>>> >  int intel_pipe_crc_create(struct drm_minor *minor);
> >>>>>> >  void intel_pipe_crc_cleanup(struct drm_minor *minor);
> >>>>>> > +#ifdef CONFIG_DEBUG_FS
> >>>>>> > +int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name,
> >>>>>> > +                        size_t *values_cnt);
> >>>>>> > +#else
> >>>>>> > +static inline int intel_crtc_set_crc_source(struct drm_crtc *crtc,
> >>>>>> > +                                      const char *source_name,
> >>>>>> > +                                      size_t *values_cnt) { return 0; }
> >>>>>> > +#endif
> >>>>>>
> >>>>>> "inline" here doesn't work because it's used as a function pointer.
> >>>>>>
> >>>>>> Is it better to have a function that returns 0 for .set_crc_source, or
> >>>>>> to set .set_crc_source to NULL when CONFIG_DEBUG_FS=n?
> >>>>>
> >>>>> I'd say that whenever we have a function pointer we should have a dummy
> >>>>> function without side-effects for this kind of things.
> >>>>
> >>>> Whoever calls .set_crc_source could do smarter things depending on the
> >>>> hook not being there vs. just silently plunging on.
> >>>
> >>> In this specific case, when CONFIG_DEBUG_FS=n it doesn't make any
> >>> sense to call that callback, so I think we should have a dummy
> >>> implementation to avoid adding an ifdef to the .c.
> >>
> >> We don't want the ifdef to the .c file, but we could do
> >>
> >> #ifdef CONFIG_DEBUG_FS
> >> int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name,
> >>                                 size_t *values_cnt);
> >> #else
> >> #define intel_crtc_set_crc_source NULL
> >> #endif
> >
> > Sounds good to me, and though I don't have any objections, wonder why
> > this isn't a common idiom in the DRM subsystem. I was able to find
> > only one instance: drm_compat_ioctl.
> 
> Heh, and it was I who suggested that too. Maybe get a second opinion. ;)

Personally I like drm_compat_ioctl, we should spread it far&wide.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

[PATCH v11 4/4] drm/i915: Put "cooked" vlank counters in frame CRC lines

[Tomeu Vizoso]

Use drm_accurate_vblank_count so we have the full 32 bit to represent
the frame counter and userspace has a simpler way of knowing when the
counter wraps around.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
---

 drivers/gpu/drm/i915/i915_irq.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 1549cc4f88ec..238a353454e9 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1495,7 +1495,6 @@ static void display_pipe_crc_irq_handler(struct drm_i915_private *dev_priv,
 	struct drm_driver *driver = dev_priv->drm.driver;
 	uint32_t crcs[5];
 	int head, tail, ret;
-	u32 frame;
 
 	spin_lock(&pipe_crc->lock);
 	if (pipe_crc->source) {
@@ -1551,8 +1550,9 @@ static void display_pipe_crc_irq_handler(struct drm_i915_private *dev_priv,
 		crcs[2] = crc2;
 		crcs[3] = crc3;
 		crcs[4] = crc4;
-		frame = driver->get_vblank_counter(&dev_priv->drm, pipe);
-		ret = drm_crtc_add_crc_entry(crtc, true, frame, crcs);
+		ret = drm_crtc_add_crc_entry(crtc, true,
+					     drm_accurate_vblank_count(crtc),
+					     crcs);
 		spin_unlock(&crtc->crc.lock);
 		if (!ret)
 			wake_up_interruptible(&crtc->crc.wq);
-- 
2.7.4