[PATCH v11 0/3] drm: add explicit fencing

[PATCH v11 0/3] drm: add explicit fencing

[Gustavo Padovan]

From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

Hi,

Hopefully the last version of the patches with the two comments from Brian
in the previous version addressed.

Robert Foss managed to port Android's drm_hwcomposer to the new HWC2 API and
added support to fences. Current patches can be seen here:

https://git.collabora.com/cgit/user/robertfoss/drm_hwcomposer.git/log/?h=hwc2_fence_v1

He ran AOSP on top of padovan/fences kernel branch with full fence support on
qemu/virgl and msm db410c. That means we already have a working open source
userspace using the explicit fencing implementation.

Also i-g-t testing are available with all tests suggested in v7 included:

https://git.collabora.com/cgit/user/padovan/intel-gpu-tools.git/log/

Please review!

Gustavo

[1] https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1253822.html

---
Gustavo Padovan (3):
  drm/fence: add in-fences support
  drm/fence: add fence timeline to drm_crtc
  drm/fence: add out-fences support

 drivers/gpu/drm/Kconfig             |   1 +
 drivers/gpu/drm/drm_atomic.c        | 255 +++++++++++++++++++++++++++++-------
 drivers/gpu/drm/drm_atomic_helper.c |   5 +
 drivers/gpu/drm/drm_crtc.c          |  45 +++++++
 drivers/gpu/drm/drm_plane.c         |   1 +
 include/drm/drm_atomic.h            |   1 +
 include/drm/drm_crtc.h              |  56 ++++++++
 7 files changed, 319 insertions(+), 45 deletions(-)

-- 
2.5.5

[PATCH v11 1/3] drm/fence: add in-fences support

[Gustavo Padovan]

From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

There is now a new property called IN_FENCE_FD attached to every plane
state that receives sync_file fds from userspace via the atomic commit
IOCTL.

The fd is then translated to a fence (that may be a fence_array
subclass or just a normal fence) and then used by DRM to fence_wait() for
all fences in the sync_file to signal. So it only commits when all
framebuffers are ready to scanout.

v2: Comments by Daniel Vetter:
	- remove set state->fence = NULL in destroy phase
	- accept fence -1 as valid and just return 0
	- do not call fence_get() - sync_file_fences_get() already calls it
	- fence_put() if state->fence is already set, in case userspace
	set the property more than once.

v3: WARN_ON if fence is set but state has no FB

v4: Comment from Maarten Lankhorst
	- allow set fence with no related fb

v5: rename FENCE_FD to IN_FENCE_FD

v6: Comments by Daniel Vetter:
	- rename plane_state->in_fence back to "fence"
	- re-introduce WARN_ON if fence set but no fb

     - rebase after fence -> dma_fence rename

v7: Comments by Brian Starkey
	- set state->fence to NULL when duplicating the state
	- fail if IN_FENCE_FD was already set

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: Brian Starkey <brian.starkey@arm.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Tested-by: Robert Foss <robert.foss@collabora.com>
---
 drivers/gpu/drm/Kconfig             |  1 +
 drivers/gpu/drm/drm_atomic.c        | 14 ++++++++++++++
 drivers/gpu/drm/drm_atomic_helper.c |  5 +++++
 drivers/gpu/drm/drm_crtc.c          |  6 ++++++
 drivers/gpu/drm/drm_plane.c         |  1 +
 include/drm/drm_crtc.h              |  5 +++++
 6 files changed, 32 insertions(+)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 863cdca..95fc041 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -12,6 +12,7 @@ menuconfig DRM
 	select I2C
 	select I2C_ALGOBIT
 	select DMA_SHARED_BUFFER
+	select SYNC_FILE
 	help
 	  Kernel-level support for the Direct Rendering Infrastructure (DRI)
 	  introduced in XFree86 4.0. If you say Y here, you need to select
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 57e0a6e9..3ad780a 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -31,6 +31,7 @@
 #include <drm/drm_mode.h>
 #include <drm/drm_plane_helper.h>
 #include <drm/drm_print.h>
+#include <linux/sync_file.h>
 
 #include "drm_crtc_internal.h"
 
@@ -712,6 +713,17 @@ int drm_atomic_plane_set_property(struct drm_plane *plane,
 		drm_atomic_set_fb_for_plane(state, fb);
 		if (fb)
 			drm_framebuffer_unreference(fb);
+	} else if (property == config->prop_in_fence_fd) {
+		if (state->fence)
+			return -EINVAL;
+
+		if (U642I64(val) == -1)
+			return 0;
+
+		state->fence = sync_file_get_fence(val);
+		if (!state->fence)
+			return -EINVAL;
+
 	} else if (property == config->prop_crtc_id) {
 		struct drm_crtc *crtc = drm_crtc_find(dev, val);
 		return drm_atomic_set_crtc_for_plane(state, crtc);
@@ -773,6 +785,8 @@ drm_atomic_plane_get_property(struct drm_plane *plane,
 
 	if (property == config->prop_fb_id) {
 		*val = (state->fb) ? state->fb->base.id : 0;
+	} else if (property == config->prop_in_fence_fd) {
+		*val = -1;
 	} else if (property == config->prop_crtc_id) {
 		*val = (state->crtc) ? state->crtc->base.id : 0;
 	} else if (property == config->prop_crtc_x) {
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 5007796..0b16587 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -3072,6 +3072,8 @@ void __drm_atomic_helper_plane_duplicate_state(struct drm_plane *plane,
 
 	if (state->fb)
 		drm_framebuffer_reference(state->fb);
+
+	state->fence = NULL;
 }
 EXPORT_SYMBOL(__drm_atomic_helper_plane_duplicate_state);
 
@@ -3110,6 +3112,9 @@ void __drm_atomic_helper_plane_destroy_state(struct drm_plane_state *state)
 {
 	if (state->fb)
 		drm_framebuffer_unreference(state->fb);
+
+	if (state->fence)
+		dma_fence_put(state->fence);
 }
 EXPORT_SYMBOL(__drm_atomic_helper_plane_destroy_state);
 
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 5745464..f6d1b38 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -397,6 +397,12 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
 		return -ENOMEM;
 	dev->mode_config.prop_fb_id = prop;
 
+	prop = drm_property_create_signed_range(dev, DRM_MODE_PROP_ATOMIC,
+			"IN_FENCE_FD", -1, INT_MAX);
+	if (!prop)
+		return -ENOMEM;
+	dev->mode_config.prop_in_fence_fd = prop;
+
 	prop = drm_property_create_object(dev, DRM_MODE_PROP_ATOMIC,
 			"CRTC_ID", DRM_MODE_OBJECT_CRTC);
 	if (!prop)
diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
index 2ba0c22..419ac31 100644
--- a/drivers/gpu/drm/drm_plane.c
+++ b/drivers/gpu/drm/drm_plane.c
@@ -137,6 +137,7 @@ int drm_universal_plane_init(struct drm_device *dev, struct drm_plane *plane,
 
 	if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
 		drm_object_attach_property(&plane->base, config->prop_fb_id, 0);
+		drm_object_attach_property(&plane->base, config->prop_in_fence_fd, -1);
 		drm_object_attach_property(&plane->base, config->prop_crtc_id, 0);
 		drm_object_attach_property(&plane->base, config->prop_crtc_x, 0);
 		drm_object_attach_property(&plane->base, config->prop_crtc_y, 0);
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 8cca2a8..11780a9 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -1214,6 +1214,11 @@ struct drm_mode_config {
 	 */
 	struct drm_property *prop_fb_id;
 	/**
+	 * @prop_in_fence_fd: Sync File fd representing the incoming fences
+	 * for a Plane.
+	 */
+	struct drm_property *prop_in_fence_fd;
+	/**
 	 * @prop_crtc_id: Default atomic plane property to specify the
 	 * &drm_crtc.
 	 */
-- 
2.5.5

[PATCH v11 2/3] drm/fence: add fence timeline to drm_crtc

[Gustavo Padovan]

From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

Create one timeline context for each CRTC to be able to handle out-fences
and signal them. It adds a few members to struct drm_crtc: fence_context,
where we store the context we get from fence_context_alloc(), the
fence seqno and the fence lock, that we pass in fence_init() to be
used by the fence.

v2: Comment by Daniel Stone:
	- add BUG_ON() to fence_to_crtc() macro

v3: Comment by Ville Syrjälä
	- Use more meaningful name as crtc timeline name

v4: Comments by Brian Starkey
	- Use even more meaninful name for the crtc timeline
	- add doc for timeline_name
    Comment by Daniel Vetter
	- use in-line style for comments

    - rebase after fence -> dma_fence rename

v5: Comment by Daniel Vetter
	- Add doc for drm_crtc_fence_ops

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Tested-by: Robert Foss <robert.foss@collabora.com>
---
 drivers/gpu/drm/drm_crtc.c | 31 +++++++++++++++++++++++++++++++
 include/drm/drm_crtc.h     | 45 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 76 insertions(+)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index f6d1b38..20ddaff 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -165,6 +165,32 @@ static void drm_crtc_crc_fini(struct drm_crtc *crtc)
 #endif
 }
 
+static const char *drm_crtc_fence_get_driver_name(struct dma_fence *fence)
+{
+	struct drm_crtc *crtc = fence_to_crtc(fence);
+
+	return crtc->dev->driver->name;
+}
+
+static const char *drm_crtc_fence_get_timeline_name(struct dma_fence *fence)
+{
+	struct drm_crtc *crtc = fence_to_crtc(fence);
+
+	return crtc->timeline_name;
+}
+
+static bool drm_crtc_fence_enable_signaling(struct dma_fence *fence)
+{
+	return true;
+}
+
+const struct dma_fence_ops drm_crtc_fence_ops = {
+	.get_driver_name = drm_crtc_fence_get_driver_name,
+	.get_timeline_name = drm_crtc_fence_get_timeline_name,
+	.enable_signaling = drm_crtc_fence_enable_signaling,
+	.wait = dma_fence_default_wait,
+};
+
 /**
  * drm_crtc_init_with_planes - Initialise a new CRTC object with
  *    specified primary and cursor planes.
@@ -222,6 +248,11 @@ int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc,
 		return -ENOMEM;
 	}
 
+	crtc->fence_context = dma_fence_context_alloc(1);
+	spin_lock_init(&crtc->fence_lock);
+	snprintf(crtc->timeline_name, sizeof(crtc->timeline_name),
+		 "CRTC:%d-%s", crtc->base.id, crtc->name);
+
 	crtc->base.properties = &crtc->properties;
 
 	list_add_tail(&crtc->head, &config->crtc_list);
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 11780a9..0870de1 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -32,6 +32,8 @@
 #include <linux/fb.h>
 #include <linux/hdmi.h>
 #include <linux/media-bus-format.h>
+#include <linux/srcu.h>
+#include <linux/dma-fence.h>
 #include <uapi/drm/drm_mode.h>
 #include <uapi/drm/drm_fourcc.h>
 #include <drm/drm_modeset_lock.h>
@@ -739,9 +741,52 @@ struct drm_crtc {
 	 */
 	struct drm_crtc_crc crc;
 #endif
+
+	/**
+	 * @fence_context:
+	 *
+	 * timeline context used for fence operations.
+	 */
+	unsigned int fence_context;
+
+	/**
+	 * @fence_lock:
+	 *
+	 * spinlock to protect the fences in the fence_context.
+	 */
+
+	spinlock_t fence_lock;
+	/**
+	 * @fence_seqno:
+	 *
+	 * Seqno variable used as monotonic counter for the fences
+	 * created on the CRTC's timeline.
+	 */
+	unsigned long fence_seqno;
+
+	/**
+	 * @timeline_name:
+	 *
+	 * The name of the CRTC's fence timeline.
+	 */
+	char timeline_name[32];
 };
 
 /**
+ * dma_crtc_fence_ops - fence ops for the drm_crtc timeline
+ *
+ * It contains the dma_fence_ops that should be called by the dma_fence
+ * code. CRTC core should use this ops when initializing fences.
+ */
+extern const struct dma_fence_ops drm_crtc_fence_ops;
+
+static inline struct drm_crtc *fence_to_crtc(struct dma_fence *fence)
+{
+	BUG_ON(fence->ops != &drm_crtc_fence_ops);
+	return container_of(fence->lock, struct drm_crtc, fence_lock);
+}
+
+/**
  * struct drm_mode_set - new values for a CRTC config change
  * @fb: framebuffer to use for new config
  * @crtc: CRTC whose configuration we're about to change
-- 
2.5.5

Re: [PATCH v11 2/3] drm/fence: add fence timeline to drm_crtc

[Chris Wilson]

On Tue, Nov 15, 2016 at 10:57:35AM +0900, Gustavo Padovan wrote:
> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> index 11780a9..0870de1 100644
> --- a/include/drm/drm_crtc.h
> +++ b/include/drm/drm_crtc.h
> @@ -32,6 +32,8 @@
>  #include <linux/fb.h>
>  #include <linux/hdmi.h>
>  #include <linux/media-bus-format.h>
> +#include <linux/srcu.h>
> +#include <linux/dma-fence.h>
>  #include <uapi/drm/drm_mode.h>
>  #include <uapi/drm/drm_fourcc.h>
>  #include <drm/drm_modeset_lock.h>
> @@ -739,9 +741,52 @@ struct drm_crtc {
>  	 */
>  	struct drm_crtc_crc crc;
>  #endif
> +
> +	/**
> +	 * @fence_context:
> +	 *
> +	 * timeline context used for fence operations.
> +	 */
> +	unsigned int fence_context;
> +
> +	/**
> +	 * @fence_lock:
> +	 *
> +	 * spinlock to protect the fences in the fence_context.
> +	 */
> +
> +	spinlock_t fence_lock;
> +	/**
> +	 * @fence_seqno:
> +	 *
> +	 * Seqno variable used as monotonic counter for the fences
> +	 * created on the CRTC's timeline.
> +	 */
> +	unsigned long fence_seqno;
> +
> +	/**
> +	 * @timeline_name:
> +	 *
> +	 * The name of the CRTC's fence timeline.
> +	 */
> +	char timeline_name[32];
>  };
>  
>  /**
> + * dma_crtc_fence_ops - fence ops for the drm_crtc timeline
> + *
> + * It contains the dma_fence_ops that should be called by the dma_fence
> + * code. CRTC core should use this ops when initializing fences.
> + */
> +extern const struct dma_fence_ops drm_crtc_fence_ops;
> +
> +static inline struct drm_crtc *fence_to_crtc(struct dma_fence *fence)
> +{
> +	BUG_ON(fence->ops != &drm_crtc_fence_ops);
> +	return container_of(fence->lock, struct drm_crtc, fence_lock);
> +}

If you are planning to export this for use by drivers, you are missing
the EXPORT_SYMBOL(drm_crtc_fence_ops).
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

Re: [PATCH v11 2/3] drm/fence: add fence timeline to drm_crtc

[Chris Wilson]

On Tue, Nov 15, 2016 at 08:25:55AM +0000, Chris Wilson wrote:
> On Tue, Nov 15, 2016 at 10:57:35AM +0900, Gustavo Padovan wrote:
> >  /**
> > + * dma_crtc_fence_ops - fence ops for the drm_crtc timeline
> > + *
> > + * It contains the dma_fence_ops that should be called by the dma_fence
> > + * code. CRTC core should use this ops when initializing fences.
> > + */
> > +extern const struct dma_fence_ops drm_crtc_fence_ops;
> > +
> > +static inline struct drm_crtc *fence_to_crtc(struct dma_fence *fence)
> > +{
> > +	BUG_ON(fence->ops != &drm_crtc_fence_ops);
> > +	return container_of(fence->lock, struct drm_crtc, fence_lock);
> > +}
> 
> If you are planning to export this for use by drivers, you are missing
> the EXPORT_SYMBOL(drm_crtc_fence_ops).

My suggestion would not to have the BUG_ON() here (saves one
checkpatch.pl complaint in exchange for a slightly more mysterious GPF).
Also please consider calling this dma_fence_to_crtc() as otherwise it
conflicts with those with plans to use struct fences on their
crtc/states.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

Re: [PATCH v11 2/3] drm/fence: add fence timeline to drm_crtc

[Gustavo Padovan]

2016-11-15 Chris Wilson <chris@chris-wilson.co.uk>:

> On Tue, Nov 15, 2016 at 10:57:35AM +0900, Gustavo Padovan wrote:
> > diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> > index 11780a9..0870de1 100644
> > --- a/include/drm/drm_crtc.h
> > +++ b/include/drm/drm_crtc.h
> > @@ -32,6 +32,8 @@
> >  #include <linux/fb.h>
> >  #include <linux/hdmi.h>
> >  #include <linux/media-bus-format.h>
> > +#include <linux/srcu.h>
> > +#include <linux/dma-fence.h>
> >  #include <uapi/drm/drm_mode.h>
> >  #include <uapi/drm/drm_fourcc.h>
> >  #include <drm/drm_modeset_lock.h>
> > @@ -739,9 +741,52 @@ struct drm_crtc {
> >  	 */
> >  	struct drm_crtc_crc crc;
> >  #endif
> > +
> > +	/**
> > +	 * @fence_context:
> > +	 *
> > +	 * timeline context used for fence operations.
> > +	 */
> > +	unsigned int fence_context;
> > +
> > +	/**
> > +	 * @fence_lock:
> > +	 *
> > +	 * spinlock to protect the fences in the fence_context.
> > +	 */
> > +
> > +	spinlock_t fence_lock;
> > +	/**
> > +	 * @fence_seqno:
> > +	 *
> > +	 * Seqno variable used as monotonic counter for the fences
> > +	 * created on the CRTC's timeline.
> > +	 */
> > +	unsigned long fence_seqno;
> > +
> > +	/**
> > +	 * @timeline_name:
> > +	 *
> > +	 * The name of the CRTC's fence timeline.
> > +	 */
> > +	char timeline_name[32];
> >  };
> >  
> >  /**
> > + * dma_crtc_fence_ops - fence ops for the drm_crtc timeline
> > + *
> > + * It contains the dma_fence_ops that should be called by the dma_fence
> > + * code. CRTC core should use this ops when initializing fences.
> > + */
> > +extern const struct dma_fence_ops drm_crtc_fence_ops;
> > +
> > +static inline struct drm_crtc *fence_to_crtc(struct dma_fence *fence)
> > +{
> > +	BUG_ON(fence->ops != &drm_crtc_fence_ops);
> > +	return container_of(fence->lock, struct drm_crtc, fence_lock);
> > +}
> 
> If you are planning to export this for use by drivers, you are missing
> the EXPORT_SYMBOL(drm_crtc_fence_ops).

Drivers should not be using this, at least for now.

Gustavo

Re: [PATCH v11 2/3] drm/fence: add fence timeline to drm_crtc

[Daniel Vetter]

On Tue, Nov 15, 2016 at 05:42:35PM +0900, Gustavo Padovan wrote:
> 2016-11-15 Chris Wilson <chris@chris-wilson.co.uk>:
> 
> > On Tue, Nov 15, 2016 at 10:57:35AM +0900, Gustavo Padovan wrote:
> > > diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> > > index 11780a9..0870de1 100644
> > > --- a/include/drm/drm_crtc.h
> > > +++ b/include/drm/drm_crtc.h
> > > @@ -32,6 +32,8 @@
> > >  #include <linux/fb.h>
> > >  #include <linux/hdmi.h>
> > >  #include <linux/media-bus-format.h>
> > > +#include <linux/srcu.h>
> > > +#include <linux/dma-fence.h>
> > >  #include <uapi/drm/drm_mode.h>
> > >  #include <uapi/drm/drm_fourcc.h>
> > >  #include <drm/drm_modeset_lock.h>
> > > @@ -739,9 +741,52 @@ struct drm_crtc {
> > >  	 */
> > >  	struct drm_crtc_crc crc;
> > >  #endif
> > > +
> > > +	/**
> > > +	 * @fence_context:
> > > +	 *
> > > +	 * timeline context used for fence operations.
> > > +	 */
> > > +	unsigned int fence_context;
> > > +
> > > +	/**
> > > +	 * @fence_lock:
> > > +	 *
> > > +	 * spinlock to protect the fences in the fence_context.
> > > +	 */
> > > +
> > > +	spinlock_t fence_lock;
> > > +	/**
> > > +	 * @fence_seqno:
> > > +	 *
> > > +	 * Seqno variable used as monotonic counter for the fences
> > > +	 * created on the CRTC's timeline.
> > > +	 */
> > > +	unsigned long fence_seqno;
> > > +
> > > +	/**
> > > +	 * @timeline_name:
> > > +	 *
> > > +	 * The name of the CRTC's fence timeline.
> > > +	 */
> > > +	char timeline_name[32];
> > >  };
> > >  
> > >  /**
> > > + * dma_crtc_fence_ops - fence ops for the drm_crtc timeline
> > > + *
> > > + * It contains the dma_fence_ops that should be called by the dma_fence
> > > + * code. CRTC core should use this ops when initializing fences.
> > > + */
> > > +extern const struct dma_fence_ops drm_crtc_fence_ops;
> > > +
> > > +static inline struct drm_crtc *fence_to_crtc(struct dma_fence *fence)
> > > +{
> > > +	BUG_ON(fence->ops != &drm_crtc_fence_ops);
> > > +	return container_of(fence->lock, struct drm_crtc, fence_lock);
> > > +}
> > 
> > If you are planning to export this for use by drivers, you are missing
> > the EXPORT_SYMBOL(drm_crtc_fence_ops).
> 
> Drivers should not be using this, at least for now.

Then please put it into drm_crtc_internal.h. We should only allow drivers
to use functions they're supposed to be using, and hide everything else.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Re: [PATCH v11 2/3] drm/fence: add fence timeline to drm_crtc

[Chris Wilson]

On Tue, Nov 15, 2016 at 05:42:35PM +0900, Gustavo Padovan wrote:
> 2016-11-15 Chris Wilson <chris@chris-wilson.co.uk>:
> 
> > On Tue, Nov 15, 2016 at 10:57:35AM +0900, Gustavo Padovan wrote:
> > > diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> > > index 11780a9..0870de1 100644
> > > --- a/include/drm/drm_crtc.h
> > > +++ b/include/drm/drm_crtc.h
> > > @@ -32,6 +32,8 @@
> > >  #include <linux/fb.h>
> > >  #include <linux/hdmi.h>
> > >  #include <linux/media-bus-format.h>
> > > +#include <linux/srcu.h>
> > > +#include <linux/dma-fence.h>
> > >  #include <uapi/drm/drm_mode.h>
> > >  #include <uapi/drm/drm_fourcc.h>
> > >  #include <drm/drm_modeset_lock.h>
> > > @@ -739,9 +741,52 @@ struct drm_crtc {
> > >  	 */
> > >  	struct drm_crtc_crc crc;
> > >  #endif
> > > +
> > > +	/**
> > > +	 * @fence_context:
> > > +	 *
> > > +	 * timeline context used for fence operations.
> > > +	 */
> > > +	unsigned int fence_context;
> > > +
> > > +	/**
> > > +	 * @fence_lock:
> > > +	 *
> > > +	 * spinlock to protect the fences in the fence_context.
> > > +	 */
> > > +
> > > +	spinlock_t fence_lock;
> > > +	/**
> > > +	 * @fence_seqno:
> > > +	 *
> > > +	 * Seqno variable used as monotonic counter for the fences
> > > +	 * created on the CRTC's timeline.
> > > +	 */
> > > +	unsigned long fence_seqno;
> > > +
> > > +	/**
> > > +	 * @timeline_name:
> > > +	 *
> > > +	 * The name of the CRTC's fence timeline.
> > > +	 */
> > > +	char timeline_name[32];
> > >  };
> > >  
> > >  /**
> > > + * dma_crtc_fence_ops - fence ops for the drm_crtc timeline
> > > + *
> > > + * It contains the dma_fence_ops that should be called by the dma_fence
> > > + * code. CRTC core should use this ops when initializing fences.
> > > + */
> > > +extern const struct dma_fence_ops drm_crtc_fence_ops;
> > > +
> > > +static inline struct drm_crtc *fence_to_crtc(struct dma_fence *fence)
> > > +{
> > > +	BUG_ON(fence->ops != &drm_crtc_fence_ops);
> > > +	return container_of(fence->lock, struct drm_crtc, fence_lock);
> > > +}
> > 
> > If you are planning to export this for use by drivers, you are missing
> > the EXPORT_SYMBOL(drm_crtc_fence_ops).
> 
> Drivers should not be using this, at least for now.

You've put into a central header, with kerneldoc on the ops, just inviting
people to use it...
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

[PATCH v11 3/3] drm/fence: add out-fences support

[Gustavo Padovan]

From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

Support DRM out-fences by creating a sync_file with a fence for each CRTC
that sets the OUT_FENCE_PTR property.

We use the out_fence pointer received in the OUT_FENCE_PTR prop to send
the sync_file fd back to userspace.

The sync_file and fd are allocated/created before commit, but the
fd_install operation only happens after we know that commit succeed.

v2: Comment by Rob Clark:
	- Squash commit that adds DRM_MODE_ATOMIC_OUT_FENCE flag here.

    Comment by Daniel Vetter:
	- Add clean up code for out_fences

v3: Comments by Daniel Vetter:
	- create DRM_MODE_ATOMIC_EVENT_MASK
	- userspace should fill out_fences_ptr with the crtc_ids for which
	it wants fences back.

v4: Create OUT_FENCE_PTR properties and remove old approach.

v5: Comments by Brian Starkey:
	- Remove extra fence_get() in atomic_ioctl()
	- Check ret before iterating on the crtc_state
	- check ret before fd_install
	- set fence_state to NULL at the beginning
	- check fence_state->out_fence_ptr before put_user()
	- change order of fput() and put_unused_fd() on failure

     - Add access_ok() check to the out_fence_ptr received
     - Rebase after fence -> dma_fence rename
     - Store out_fence_ptr in the drm_atomic_state
     - Split crtc_setup_out_fence()
     - return -1 as out_fence with TEST_ONLY flag

v6: Comments by Daniel Vetter
	- Add prepare/unprepare_crtc_signaling()
	- move struct drm_out_fence_state to drm_atomic.c
	- mark get_crtc_fence() as static

    Comments by Brian Starkey
	- proper set fence_ptr fence_state array
	- isolate fence_idx increment

    - improve error handling

v7: Comments by Daniel Vetter
	- remove prefix from internal functions
	- make out_fence_ptr an s64 pointer
	- degrade DRM_INFO to DRM_DEBUG_ATOMIC when put_user fail
	- fix doc issues
	- filter out OUT_FENCE_PTR == NULL and do not fail in this case
	- add complete_crtc_signalling()
	- krealloc fence_state on demand

    Comment by Brian Starkey
	- remove unused crtc_state arg from get_out_fence()

v8: Comment by Brian Starkey
	- cancel events before check for !fence_state
	- convert a few lefovers u64 types for out_fence_ptr
	- fix memleak by assign fence_state earlier after realloc
	- proper accout num_fences in case of error

v9: Comment by Brian Starkey
	- memset last position of fence_state after krealloc
    Comments by Sean Paul
	- pass install_fds in complete_crtc_signaling() instead of ret

     - put_user(-1, fence_ptr) when decoding props

v10: Comment by Brian Starkey
	- remove unneeded num_fences increment on error path
	- kfree fence_state after installing fences fd

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: Brian Starkey <brian.starkey@arm.com>
Tested-by: Robert Foss <robert.foss@collabora.com>
---
 drivers/gpu/drm/drm_atomic.c | 241 +++++++++++++++++++++++++++++++++++--------
 drivers/gpu/drm/drm_crtc.c   |   8 ++
 include/drm/drm_atomic.h     |   1 +
 include/drm/drm_crtc.h       |   6 ++
 4 files changed, 211 insertions(+), 45 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 3ad780a..d4a92a9 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -290,6 +290,23 @@ drm_atomic_get_crtc_state(struct drm_atomic_state *state,
 }
 EXPORT_SYMBOL(drm_atomic_get_crtc_state);
 
+static void set_out_fence_for_crtc(struct drm_atomic_state *state,
+				   struct drm_crtc *crtc, s64 __user *fence_ptr)
+{
+	state->crtcs[drm_crtc_index(crtc)].out_fence_ptr = fence_ptr;
+}
+
+static s64 __user * get_out_fence_for_crtc(struct drm_atomic_state *state,
+					   struct drm_crtc *crtc)
+{
+	s64 __user *fence_ptr;
+
+	fence_ptr = state->crtcs[drm_crtc_index(crtc)].out_fence_ptr;
+	state->crtcs[drm_crtc_index(crtc)].out_fence_ptr = NULL;
+
+	return fence_ptr;
+}
+
 /**
  * drm_atomic_set_mode_for_crtc - set mode for CRTC
  * @state: the CRTC whose incoming state to update
@@ -494,6 +511,16 @@ int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
 					&replaced);
 		state->color_mgmt_changed |= replaced;
 		return ret;
+	} else if (property == config->prop_out_fence_ptr) {
+		s64 __user *fence_ptr = u64_to_user_ptr(val);
+
+		if (!fence_ptr)
+			return 0;
+
+		if (put_user(-1, fence_ptr))
+			return -EFAULT;
+
+		set_out_fence_for_crtc(state->state, crtc, fence_ptr);
 	} else if (crtc->funcs->atomic_set_property)
 		return crtc->funcs->atomic_set_property(crtc, state, property, val);
 	else
@@ -536,6 +563,8 @@ drm_atomic_crtc_get_property(struct drm_crtc *crtc,
 		*val = (state->ctm) ? state->ctm->base.id : 0;
 	else if (property == config->gamma_lut_property)
 		*val = (state->gamma_lut) ? state->gamma_lut->base.id : 0;
+	else if (property == config->prop_out_fence_ptr)
+		*val = 0;
 	else if (crtc->funcs->atomic_get_property)
 		return crtc->funcs->atomic_get_property(crtc, state, property, val);
 	else
@@ -1664,11 +1693,9 @@ int drm_atomic_debugfs_init(struct drm_minor *minor)
  */
 
 static struct drm_pending_vblank_event *create_vblank_event(
-		struct drm_device *dev, struct drm_file *file_priv,
-		struct dma_fence *fence, uint64_t user_data)
+		struct drm_device *dev, uint64_t user_data)
 {
 	struct drm_pending_vblank_event *e = NULL;
-	int ret;
 
 	e = kzalloc(sizeof *e, GFP_KERNEL);
 	if (!e)
@@ -1678,17 +1705,6 @@ static struct drm_pending_vblank_event *create_vblank_event(
 	e->event.base.length = sizeof(e->event);
 	e->event.user_data = user_data;
 
-	if (file_priv) {
-		ret = drm_event_reserve_init(dev, file_priv, &e->base,
-					     &e->event.base);
-		if (ret) {
-			kfree(e);
-			return NULL;
-		}
-	}
-
-	e->base.fence = fence;
-
 	return e;
 }
 
@@ -1793,6 +1809,165 @@ void drm_atomic_clean_old_fb(struct drm_device *dev,
 }
 EXPORT_SYMBOL(drm_atomic_clean_old_fb);
 
+static struct dma_fence *get_crtc_fence(struct drm_crtc *crtc)
+{
+	struct dma_fence *fence;
+
+	fence = kzalloc(sizeof(*fence), GFP_KERNEL);
+	if (!fence)
+		return NULL;
+
+	dma_fence_init(fence, &drm_crtc_fence_ops, &crtc->fence_lock,
+		       crtc->fence_context, ++crtc->fence_seqno);
+
+	return fence;
+}
+
+struct drm_out_fence_state {
+	s64 __user *out_fence_ptr;
+	struct sync_file *sync_file;
+	int fd;
+};
+
+static int setup_out_fence(struct drm_out_fence_state *fence_state,
+			   struct dma_fence *fence)
+{
+	fence_state->fd = get_unused_fd_flags(O_CLOEXEC);
+	if (fence_state->fd < 0)
+		return fence_state->fd;
+
+	if (put_user(fence_state->fd, fence_state->out_fence_ptr))
+		return -EFAULT;
+
+	fence_state->sync_file = sync_file_create(fence);
+	if(!fence_state->sync_file)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static int prepare_crtc_signaling(struct drm_device *dev,
+				  struct drm_atomic_state *state,
+				  struct drm_mode_atomic *arg,
+				  struct drm_file *file_priv,
+				  struct drm_out_fence_state **fence_state,
+				  unsigned int *num_fences)
+{
+	struct drm_crtc *crtc;
+	struct drm_crtc_state *crtc_state;
+	int i, ret;
+
+	if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY)
+		return 0;
+
+	for_each_crtc_in_state(state, crtc, crtc_state, i) {
+		u64 __user *fence_ptr;
+
+		fence_ptr = get_out_fence_for_crtc(crtc_state->state, crtc);
+
+		if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT || fence_ptr) {
+			struct drm_pending_vblank_event *e;
+
+			e = create_vblank_event(dev, arg->user_data);
+			if (!e)
+				return -ENOMEM;
+
+			crtc_state->event = e;
+		}
+
+		if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
+			struct drm_pending_vblank_event *e = crtc_state->event;
+
+			if (!file_priv)
+				continue;
+
+			ret = drm_event_reserve_init(dev, file_priv, &e->base,
+						     &e->event.base);
+			if (ret) {
+				kfree(e);
+				crtc_state->event = NULL;
+				return ret;
+			}
+		}
+
+		if (fence_ptr) {
+			struct dma_fence *fence;
+			struct drm_out_fence_state *f;
+
+			f = krealloc(*fence_state, sizeof(**fence_state) *
+				     (*num_fences + 1), GFP_KERNEL);
+			if (!f)
+				return -ENOMEM;
+
+			memset(&f[*num_fences], 0, sizeof(*f));
+
+			f[*num_fences].out_fence_ptr = fence_ptr;
+			*fence_state = f;
+
+			fence = get_crtc_fence(crtc);
+			if (!fence)
+				return -ENOMEM;
+
+			ret = setup_out_fence(&f[(*num_fences)++], fence);
+			if (ret) {
+				dma_fence_put(fence);
+				return ret;
+			}
+
+			crtc_state->event->base.fence = fence;
+		}
+	}
+
+	return 0;
+}
+
+static void complete_crtc_signaling(struct drm_device *dev,
+				     struct drm_atomic_state *state,
+				     struct drm_out_fence_state *fence_state,
+				     unsigned int num_fences,
+				     bool install_fds)
+{
+	struct drm_crtc *crtc;
+	struct drm_crtc_state *crtc_state;
+	int i;
+
+	if (install_fds) {
+		for (i = 0; i < num_fences; i++)
+			fd_install(fence_state[i].fd,
+				   fence_state[i].sync_file->file);
+
+		kfree(fence_state);
+		return;
+	}
+
+	for_each_crtc_in_state(state, crtc, crtc_state, i) {
+		/*
+		 * TEST_ONLY and PAGE_FLIP_EVENT are mutually
+		 * exclusive, if they weren't, this code should be
+		 * called on success for TEST_ONLY too.
+		 */
+		if (crtc_state->event)
+			drm_event_cancel_free(dev, &crtc_state->event->base);
+	}
+
+	if (!fence_state)
+		return;
+
+	for (i = 0; i < num_fences; i++) {
+		if (fence_state[i].sync_file)
+			fput(fence_state[i].sync_file->file);
+		if (fence_state[i].fd >= 0)
+			put_unused_fd(fence_state[i].fd);
+
+		/* If this fails log error to the user */
+		if (fence_state[i].out_fence_ptr &&
+		    put_user(-1, fence_state[i].out_fence_ptr))
+			DRM_DEBUG_ATOMIC("Couldn't clear out_fence_ptr\n");
+	}
+
+	kfree(fence_state);
+}
+
 int drm_mode_atomic_ioctl(struct drm_device *dev,
 			  void *data, struct drm_file *file_priv)
 {
@@ -1805,11 +1980,10 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
 	struct drm_atomic_state *state;
 	struct drm_modeset_acquire_ctx ctx;
 	struct drm_plane *plane;
-	struct drm_crtc *crtc;
-	struct drm_crtc_state *crtc_state;
+	struct drm_out_fence_state *fence_state = NULL;
 	unsigned plane_mask;
 	int ret = 0;
-	unsigned int i, j;
+	unsigned int i, j, num_fences = 0;
 
 	/* disallow for drivers not supporting atomic: */
 	if (!drm_core_check_feature(dev, DRIVER_ATOMIC))
@@ -1924,20 +2098,10 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
 		drm_mode_object_unreference(obj);
 	}
 
-	if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
-		for_each_crtc_in_state(state, crtc, crtc_state, i) {
-			struct drm_pending_vblank_event *e;
-
-			e = create_vblank_event(dev, file_priv, NULL,
-						arg->user_data);
-			if (!e) {
-				ret = -ENOMEM;
-				goto out;
-			}
-
-			crtc_state->event = e;
-		}
-	}
+	ret = prepare_crtc_signaling(dev, state, arg, file_priv, &fence_state,
+				     &num_fences);
+	if (ret)
+		goto out;
 
 	if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY) {
 		/*
@@ -1957,20 +2121,7 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
 out:
 	drm_atomic_clean_old_fb(dev, plane_mask, ret);
 
-	if (ret && arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
-		/*
-		 * TEST_ONLY and PAGE_FLIP_EVENT are mutually exclusive,
-		 * if they weren't, this code should be called on success
-		 * for TEST_ONLY too.
-		 */
-
-		for_each_crtc_in_state(state, crtc, crtc_state, i) {
-			if (!crtc_state->event)
-				continue;
-
-			drm_event_cancel_free(dev, &crtc_state->event->base);
-		}
-	}
+	complete_crtc_signaling(dev, state, fence_state, num_fences, !ret);
 
 	if (ret == -EDEADLK) {
 		drm_atomic_state_clear(state);
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 20ddaff..cf2423d 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -274,6 +274,8 @@ int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc,
 	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);
+		drm_object_attach_property(&crtc->base,
+					   config->prop_out_fence_ptr, 0);
 	}
 
 	return 0;
@@ -434,6 +436,12 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
 		return -ENOMEM;
 	dev->mode_config.prop_in_fence_fd = prop;
 
+	prop = drm_property_create_range(dev, DRM_MODE_PROP_ATOMIC,
+			"OUT_FENCE_PTR", 0, U64_MAX);
+	if (!prop)
+		return -ENOMEM;
+	dev->mode_config.prop_out_fence_ptr = prop;
+
 	prop = drm_property_create_object(dev, DRM_MODE_PROP_ATOMIC,
 			"CRTC_ID", DRM_MODE_OBJECT_CRTC);
 	if (!prop)
diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
index 331bb10..c0eaec7 100644
--- a/include/drm/drm_atomic.h
+++ b/include/drm/drm_atomic.h
@@ -144,6 +144,7 @@ struct __drm_crtcs_state {
 	struct drm_crtc *ptr;
 	struct drm_crtc_state *state;
 	struct drm_crtc_commit *commit;
+	s64 __user *out_fence_ptr;
 };
 
 struct __drm_connnectors_state {
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 0870de1..44571bc 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -1264,6 +1264,12 @@ struct drm_mode_config {
 	 */
 	struct drm_property *prop_in_fence_fd;
 	/**
+	 * @prop_out_fence_ptr: Sync File fd pointer representing the
+	 * outgoing fences for a CRTC. Userspace should provide a pointer to a
+	 * value of type s64, and then cast that pointer to u64.
+	 */
+	struct drm_property *prop_out_fence_ptr;
+	/**
 	 * @prop_crtc_id: Default atomic plane property to specify the
 	 * &drm_crtc.
 	 */
-- 
2.5.5