[PATCH 14/16] drm/vblank: drop the mode argument from drm_calc_vbltimestamp_from_scanoutpos

[Daniel Vetter <daniel.vetter@ffwll.ch>]

If we restrict this helper to only kms drivers (which is the case) we
can look up the correct mode easily ourselves. But it's a bit tricky:

- All legacy drivers look at crtc->hwmode. But that is update already
  at the beginning of the modeset helper, which means when we disable
  a pipe. Hence the final timestamps might be a bit off. But since
  this is an existing bug I'm not going to change it, but just try to
  be bug-for-bug compatible with the current code. This only applies
  to radeon&amdgpu.

- i915 tries to get it perfect by updating crtc->hwmode when the pipe
  is off (i.e. vblank->enabled = false).

- All other atomic drivers look at crtc->state->adjusted_mode. Those
  that look at state->requested_mode simply don't adjust their mode,
  so it's the same. That has two problems: Accessing crtc->state from
  interrupt handling code is unsafe, and it's updated before we shut
  down the pipe. For nonblocking modesets it's even worse.

For atomic drivers try to implement what i915 does. To do that we add
a new hwmode field to the vblank structure, and update it from
drm_calc_timestamping_constants(). For atomic drivers that's called
from the right spot by the helper library already, so all fine. But
for safety let's enforce that.

For legacy driver this function is only called at the end (oh the
fun), which is broken, so again let's not bother and just stay
bug-for-bug compatible.

The  benefit is that we can use drm_calc_vbltimestamp_from_scanoutpos
directly to implement ->get_vblank_timestamp in every driver, deleting
a lot of code.

v2: Completely new approach, trying to mimick the i915 solution.

v3: Fixup kerneldoc.

Cc: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Cc: Eric Anholt <eric@anholt.net>
Cc: Rob Clark <robdclark@gmail.com>
Cc: linux-arm-msm@vger.kernel.org
Cc: freedreno@lists.freedesktop.org
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu.h       |  4 ---
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c   |  2 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c   | 41 -------------------------------
 drivers/gpu/drm/drm_irq.c                 | 29 +++++++++++++++++++---
 drivers/gpu/drm/i915/i915_irq.c           | 33 +------------------------
 drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c   | 26 +-------------------
 drivers/gpu/drm/nouveau/nouveau_display.c | 22 -----------------
 drivers/gpu/drm/nouveau/nouveau_display.h |  2 --
 drivers/gpu/drm/nouveau/nouveau_drm.c     |  2 +-
 drivers/gpu/drm/radeon/radeon_drv.c       |  6 +----
 drivers/gpu/drm/radeon/radeon_kms.c       | 37 ----------------------------
 drivers/gpu/drm/vc4/vc4_crtc.c            | 13 ----------
 drivers/gpu/drm/vc4/vc4_drv.c             |  2 +-
 drivers/gpu/drm/vc4/vc4_drv.h             |  3 ---
 include/drm/drm_irq.h                     | 15 +++++++++--
 15 files changed, 44 insertions(+), 193 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index edb3bb83e1a9..61bef9609b24 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -1768,10 +1768,6 @@ int amdgpu_device_resume(struct drm_device *dev, bool resume, bool fbcon);
 u32 amdgpu_get_vblank_counter_kms(struct drm_device *dev, unsigned int pipe);
 int amdgpu_enable_vblank_kms(struct drm_device *dev, unsigned int pipe);
 void amdgpu_disable_vblank_kms(struct drm_device *dev, unsigned int pipe);
-bool amdgpu_get_vblank_timestamp_kms(struct drm_device *dev, unsigned int pipe,
-				     int *max_error,
-				     struct timeval *vblank_time,
-				     bool in_vblank_irq);
 long amdgpu_kms_compat_ioctl(struct file *filp, unsigned int cmd,
 			     unsigned long arg);
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 8a61296fd4cc..ba169a0699d5 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -692,7 +692,7 @@ static struct drm_driver kms_driver = {
 	.get_vblank_counter = amdgpu_get_vblank_counter_kms,
 	.enable_vblank = amdgpu_enable_vblank_kms,
 	.disable_vblank = amdgpu_disable_vblank_kms,
-	.get_vblank_timestamp = amdgpu_get_vblank_timestamp_kms,
+	.get_vblank_timestamp = drm_calc_vbltimestamp_from_scanoutpos,
 	.get_scanout_position = amdgpu_get_crtc_scanoutpos,
 #if defined(CONFIG_DEBUG_FS)
 	.debugfs_init = amdgpu_debugfs_init,
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
index ad295e822d45..32a492bd4e51 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
@@ -827,47 +827,6 @@ void amdgpu_disable_vblank_kms(struct drm_device *dev, unsigned int pipe)
 	amdgpu_irq_put(adev, &adev->crtc_irq, idx);
 }
 
-/**
- * amdgpu_get_vblank_timestamp_kms - get vblank timestamp
- *
- * @dev: drm dev pointer
- * @crtc: crtc to get the timestamp for
- * @max_error: max error
- * @vblank_time: time value
- * @in_vblank_irq: called from drm_handle_vblank()
- *
- * Gets the timestamp on the requested crtc based on the
- * scanout position.  (all asics).
- * Returns true on success, false on failure.
- */
-bool amdgpu_get_vblank_timestamp_kms(struct drm_device *dev, unsigned int pipe,
-				     int *max_error,
-				     struct timeval *vblank_time,
-				     bool in_vblank_irq)
-{
-	struct drm_crtc *crtc;
-	struct amdgpu_device *adev = dev->dev_private;
-
-	if (pipe >= dev->num_crtcs) {
-		DRM_ERROR("Invalid crtc %u\n", pipe);
-		return false;
-	}
-
-	/* Get associated drm_crtc: */
-	crtc = &adev->mode_info.crtcs[pipe]->base;
-	if (!crtc) {
-		/* This can occur on driver load if some component fails to
-		 * initialize completely and driver is unloaded */
-		DRM_ERROR("Uninitialized crtc %d\n", pipe);
-		return false;
-	}
-
-	/* Helper routine in DRM core does all the work: */
-	return drm_calc_vbltimestamp_from_scanoutpos(dev, pipe, max_error,
-						     vblank_time, in_vblank_irq,
-						     &crtc->hwmode);
-}
-
 const struct drm_ioctl_desc amdgpu_ioctls_kms[] = {
 	DRM_IOCTL_DEF_DRV(AMDGPU_GEM_CREATE, amdgpu_gem_create_ioctl, DRM_AUTH|DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(AMDGPU_CTX, amdgpu_ctx_ioctl, DRM_AUTH|DRM_RENDER_ALLOW),
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 059c3346db68..61d726b1f810 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -659,6 +659,8 @@ void drm_calc_timestamping_constants(struct drm_crtc *crtc,
 	if (WARN_ON(pipe >= dev->num_crtcs))
 		return;
 
+	WARN_ON(drm_drv_uses_atomic_modeset(dev) && vblank->enabled);
+
 	/* Valid dotclock? */
 	if (dotclock > 0) {
 		int frame_size = mode->crtc_htotal * mode->crtc_vtotal;
@@ -682,6 +684,7 @@ void drm_calc_timestamping_constants(struct drm_crtc *crtc,
 
 	vblank->linedur_ns  = linedur_ns;
 	vblank->framedur_ns = framedur_ns;
+	vblank->hwmode = *mode;
 
 	DRM_DEBUG("crtc %u: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
 		  crtc->base.id, mode->crtc_htotal,
@@ -702,7 +705,6 @@ EXPORT_SYMBOL(drm_calc_timestamping_constants);
  *     True when called from drm_crtc_handle_vblank().  Some drivers
  *     need to apply some workarounds for gpu-specific vblank irq quirks
  *     if flag is set.
- * @mode: mode which defines the scanout timings
  *
  * Implements calculation of exact vblank timestamps from given drm_display_mode
  * timings and current video scanout position of a CRTC. This can be called from
@@ -722,6 +724,13 @@ EXPORT_SYMBOL(drm_calc_timestamping_constants);
  * returns as no operation if a doublescan or interlaced video mode is
  * active. Higher level code is expected to handle this.
  *
+ * This function can be used to implement the &drm_driver.get_vblank_timestamp
+ * directly, if the driver implements the &drm_driver.get_scanout_position hook.
+ *
+ * Note that atomic drivers must call drm_calc_timestamping_constants() before
+ * enabling a CRTC. The atomic helpers already take care of that in
+ * drm_atomic_helper_update_legacy_modeset_state().
+ *
  * Returns:
  *
  * Returns true on success, and false on failure, i.e. when no accurate
@@ -731,17 +740,24 @@ bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
 					   unsigned int pipe,
 					   int *max_error,
 					   struct timeval *vblank_time,
-					   bool in_vblank_irq,
-					   const struct drm_display_mode *mode)
+					   bool in_vblank_irq)
 {
 	struct timeval tv_etime;
 	ktime_t stime, etime;
 	unsigned int vbl_status;
+	struct drm_crtc *crtc;
+	const struct drm_display_mode *mode;
+	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
 	int vpos, hpos, i;
 	int delta_ns, duration_ns;
 	unsigned flags = in_vblank_irq ? DRM_CALLED_FROM_VBLIRQ : 0;
 
-	if (pipe >= dev->num_crtcs) {
+	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+		return false;
+
+	crtc = drm_crtc_from_index(dev, pipe);
+
+	if (pipe >= dev->num_crtcs || !crtc) {
 		DRM_ERROR("Invalid crtc %u\n", pipe);
 		return false;
 	}
@@ -752,6 +768,11 @@ bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
 		return false;
 	}
 
+	if (drm_drv_uses_atomic_modeset(dev))
+		mode = &vblank->hwmode;
+	else
+		mode = &crtc->hwmode;
+
 	/* If mode timing undefined, just return as no-op:
 	 * Happens during initial modesetting of a crtc.
 	 */
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 6c8a7e1284c3..feadfea77354 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -964,37 +964,6 @@ int intel_get_crtc_scanline(struct intel_crtc *crtc)
 	return position;
 }
 
-static bool i915_get_vblank_timestamp(struct drm_device *dev, unsigned int pipe,
-			      int *max_error,
-			      struct timeval *vblank_time,
-			      bool in_vblank_irq)
-{
-	struct drm_i915_private *dev_priv = to_i915(dev);
-	struct intel_crtc *crtc;
-
-	if (pipe >= INTEL_INFO(dev_priv)->num_pipes) {
-		DRM_ERROR("Invalid crtc %u\n", pipe);
-		return false;
-	}
-
-	/* Get drm_crtc to timestamp: */
-	crtc = intel_get_crtc_for_pipe(dev_priv, pipe);
-	if (crtc == NULL) {
-		DRM_ERROR("Invalid crtc %u\n", pipe);
-		return false;
-	}
-
-	if (!crtc->base.hwmode.crtc_clock) {
-		DRM_DEBUG_KMS("crtc %u is disabled\n", pipe);
-		return false;
-	}
-
-	/* Helper routine in DRM core does all the work: */
-	return drm_calc_vbltimestamp_from_scanoutpos(dev, pipe, max_error,
-						     vblank_time, in_vblank_irq,
-						     &crtc->base.hwmode);
-}
-
 static void ironlake_rps_change_irq_handler(struct drm_i915_private *dev_priv)
 {
 	u32 busy_up, busy_down, max_avg, min_avg;
@@ -4328,7 +4297,7 @@ void intel_irq_init(struct drm_i915_private *dev_priv)
 
 	dev_priv->hotplug.hpd_storm_threshold = HPD_STORM_DEFAULT_THRESHOLD;
 
-	dev->driver->get_vblank_timestamp = i915_get_vblank_timestamp;
+	dev->driver->get_vblank_timestamp = drm_calc_vbltimestamp_from_scanoutpos;
 	dev->driver->get_scanout_position = i915_get_crtc_scanoutpos;
 
 	if (IS_CHERRYVIEW(dev_priv)) {
diff --git a/drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c b/drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c
index 16184ccbdd3b..6ba216b8bba9 100644
--- a/drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c
+++ b/drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c
@@ -595,30 +595,6 @@ static int mdp5_get_scanoutpos(struct drm_device *dev, unsigned int pipe,
 	return ret;
 }
 
-static bool mdp5_get_vblank_timestamp(struct drm_device *dev, unsigned int pipe,
-				      int *max_error,
-				      struct timeval *vblank_time,
-				      bool in_vblank_irq)
-{
-	struct msm_drm_private *priv = dev->dev_private;
-	struct drm_crtc *crtc;
-
-	if (pipe < 0 || pipe >= priv->num_crtcs) {
-		DRM_ERROR("Invalid crtc %d\n", pipe);
-		return false;
-	}
-
-	crtc = priv->crtcs[pipe];
-	if (!crtc) {
-		DRM_ERROR("Invalid crtc %d\n", pipe);
-		return false;
-	}
-
-	return drm_calc_vbltimestamp_from_scanoutpos(dev, pipe, max_error,
-						     vblank_time, in_vblank_irq,
-						     &crtc->mode);
-}
-
 static u32 mdp5_get_vblank_counter(struct drm_device *dev, unsigned int pipe)
 {
 	struct msm_drm_private *priv = dev->dev_private;
@@ -728,7 +704,7 @@ struct msm_kms *mdp5_kms_init(struct drm_device *dev)
 	dev->mode_config.max_width = 0xffff;
 	dev->mode_config.max_height = 0xffff;
 
-	dev->driver->get_vblank_timestamp = mdp5_get_vblank_timestamp;
+	dev->driver->get_vblank_timestamp = drm_calc_vbltimestamp_from_scanoutpos;
 	dev->driver->get_scanout_position = mdp5_get_scanoutpos;
 	dev->driver->get_vblank_counter = mdp5_get_vblank_counter;
 	dev->max_vblank_count = 0xffffffff;
diff --git a/drivers/gpu/drm/nouveau/nouveau_display.c b/drivers/gpu/drm/nouveau/nouveau_display.c
index be8ec18ba126..e4bdac13d4e9 100644
--- a/drivers/gpu/drm/nouveau/nouveau_display.c
+++ b/drivers/gpu/drm/nouveau/nouveau_display.c
@@ -156,28 +156,6 @@ nouveau_display_scanoutpos(struct drm_device *dev, unsigned int pipe,
 	return 0;
 }
 
-bool
-nouveau_display_vblstamp(struct drm_device *dev, unsigned int pipe,
-			 int *max_error, struct timeval *time, bool in_vblank_irq)
-{
-	struct drm_crtc *crtc;
-
-	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
-		if (nouveau_crtc(crtc)->index == pipe) {
-			struct drm_display_mode *mode;
-			if (drm_drv_uses_atomic_modeset(dev))
-				mode = &crtc->state->adjusted_mode;
-			else
-				mode = &crtc->hwmode;
-			return drm_calc_vbltimestamp_from_scanoutpos(dev,
-					pipe, max_error, time, in_vblank_irq,
-					mode);
-		}
-	}
-
-	return false;
-}
-
 static void
 nouveau_display_vblank_fini(struct drm_device *dev)
 {
diff --git a/drivers/gpu/drm/nouveau/nouveau_display.h b/drivers/gpu/drm/nouveau/nouveau_display.h
index f821fc9e2de3..8360a85ed5ef 100644
--- a/drivers/gpu/drm/nouveau/nouveau_display.h
+++ b/drivers/gpu/drm/nouveau/nouveau_display.h
@@ -71,8 +71,6 @@ void nouveau_display_vblank_disable(struct drm_device *, unsigned int);
 int  nouveau_display_scanoutpos(struct drm_device *, unsigned int,
 				unsigned int, int *, int *, ktime_t *,
 				ktime_t *, const struct drm_display_mode *);
-bool  nouveau_display_vblstamp(struct drm_device *, unsigned int, int *,
-			       struct timeval *, bool);
 
 int  nouveau_crtc_page_flip(struct drm_crtc *crtc, struct drm_framebuffer *fb,
 			    struct drm_pending_vblank_event *event,
diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
index ec719df619a6..1f751a3f570c 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
@@ -978,7 +978,7 @@ driver_stub = {
 	.enable_vblank = nouveau_display_vblank_enable,
 	.disable_vblank = nouveau_display_vblank_disable,
 	.get_scanout_position = nouveau_display_scanoutpos,
-	.get_vblank_timestamp = nouveau_display_vblstamp,
+	.get_vblank_timestamp = drm_calc_vbltimestamp_from_scanoutpos,
 
 	.ioctls = nouveau_ioctls,
 	.num_ioctls = ARRAY_SIZE(nouveau_ioctls),
diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
index 5fbbc6ac165d..a4bf09cd33f7 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.c
+++ b/drivers/gpu/drm/radeon/radeon_drv.c
@@ -114,10 +114,6 @@ int radeon_resume_kms(struct drm_device *dev, bool resume, bool fbcon);
 u32 radeon_get_vblank_counter_kms(struct drm_device *dev, unsigned int pipe);
 int radeon_enable_vblank_kms(struct drm_device *dev, unsigned int pipe);
 void radeon_disable_vblank_kms(struct drm_device *dev, unsigned int pipe);
-bool radeon_get_vblank_timestamp_kms(struct drm_device *dev, unsigned int pipe,
-				     int *max_error,
-				     struct timeval *vblank_time,
-				     bool in_vblank_irq);
 void radeon_driver_irq_preinstall_kms(struct drm_device *dev);
 int radeon_driver_irq_postinstall_kms(struct drm_device *dev);
 void radeon_driver_irq_uninstall_kms(struct drm_device *dev);
@@ -543,7 +539,7 @@ static struct drm_driver kms_driver = {
 	.get_vblank_counter = radeon_get_vblank_counter_kms,
 	.enable_vblank = radeon_enable_vblank_kms,
 	.disable_vblank = radeon_disable_vblank_kms,
-	.get_vblank_timestamp = radeon_get_vblank_timestamp_kms,
+	.get_vblank_timestamp = drm_calc_vbltimestamp_from_scanoutpos,
 	.get_scanout_position = radeon_get_crtc_scanoutpos,
 	.irq_preinstall = radeon_driver_irq_preinstall_kms,
 	.irq_postinstall = radeon_driver_irq_postinstall_kms,
diff --git a/drivers/gpu/drm/radeon/radeon_kms.c b/drivers/gpu/drm/radeon/radeon_kms.c
index 41765d18f863..33b8b3d22969 100644
--- a/drivers/gpu/drm/radeon/radeon_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_kms.c
@@ -857,43 +857,6 @@ void radeon_disable_vblank_kms(struct drm_device *dev, int crtc)
 	spin_unlock_irqrestore(&rdev->irq.lock, irqflags);
 }
 
-/**
- * radeon_get_vblank_timestamp_kms - get vblank timestamp
- *
- * @dev: drm dev pointer
- * @crtc: crtc to get the timestamp for
- * @max_error: max error
- * @vblank_time: time value
- * @flags: flags passed to the driver
- *
- * Gets the timestamp on the requested crtc based on the
- * scanout position.  (all asics).
- * Returns true on success, false on failure.
- */
-bool radeon_get_vblank_timestamp_kms(struct drm_device *dev, int crtc,
-				     int *max_error,
-				     struct timeval *vblank_time,
-				     bool in_vblank_irq)
-{
-	struct drm_crtc *drmcrtc;
-	struct radeon_device *rdev = dev->dev_private;
-
-	if (crtc < 0 || crtc >= dev->num_crtcs) {
-		DRM_ERROR("Invalid crtc %d\n", crtc);
-		return false;
-	}
-
-	/* Get associated drm_crtc: */
-	drmcrtc = &rdev->mode_info.crtcs[crtc]->base;
-	if (!drmcrtc)
-		return false;
-
-	/* Helper routine in DRM core does all the work: */
-	return drm_calc_vbltimestamp_from_scanoutpos(dev, crtc, max_error,
-						     vblank_time, in_vblank_irq,
-						     &drmcrtc->hwmode);
-}
-
 const struct drm_ioctl_desc radeon_ioctls_kms[] = {
 	DRM_IOCTL_DEF_DRV(RADEON_CP_INIT, drm_invalid_op, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
 	DRM_IOCTL_DEF_DRV(RADEON_CP_START, drm_invalid_op, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c
index 18bd0d816fe3..2567d6c9a4ee 100644
--- a/drivers/gpu/drm/vc4/vc4_crtc.c
+++ b/drivers/gpu/drm/vc4/vc4_crtc.c
@@ -270,19 +270,6 @@ int vc4_crtc_get_scanoutpos(struct drm_device *dev, unsigned int crtc_id,
 	return ret;
 }
 
-bool vc4_crtc_get_vblank_timestamp(struct drm_device *dev, unsigned int crtc_id,
-				  int *max_error, struct timeval *vblank_time,
-				  bool in_vblank_irq)
-{
-	struct drm_crtc *crtc = drm_crtc_from_index(dev, crtc_id);
-	struct drm_crtc_state *state = crtc->state;
-
-	/* Helper routine in DRM core does all the work: */
-	return drm_calc_vbltimestamp_from_scanoutpos(dev, crtc_id, max_error,
-						     vblank_time, in_vblank_irq,
-						     &state->adjusted_mode);
-}
-
 static void vc4_crtc_destroy(struct drm_crtc *crtc)
 {
 	drm_crtc_cleanup(crtc);
diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
index 61e674baf3a6..e864256e12e5 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.c
+++ b/drivers/gpu/drm/vc4/vc4_drv.c
@@ -154,7 +154,7 @@ static struct drm_driver vc4_drm_driver = {
 	.irq_uninstall = vc4_irq_uninstall,
 
 	.get_scanout_position = vc4_crtc_get_scanoutpos,
-	.get_vblank_timestamp = vc4_crtc_get_vblank_timestamp,
+	.get_vblank_timestamp = drm_calc_vbltimestamp_from_scanoutpos,
 
 #if defined(CONFIG_DEBUG_FS)
 	.debugfs_init = vc4_debugfs_init,
diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
index 815cdeb54971..64c92e0eb8f7 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -450,9 +450,6 @@ int vc4_crtc_get_scanoutpos(struct drm_device *dev, unsigned int crtc_id,
 			    unsigned int flags, int *vpos, int *hpos,
 			    ktime_t *stime, ktime_t *etime,
 			    const struct drm_display_mode *mode);
-bool vc4_crtc_get_vblank_timestamp(struct drm_device *dev, unsigned int crtc_id,
-				  int *max_error, struct timeval *vblank_time,
-				  bool in_vblank_irq);
 
 /* vc4_debugfs.c */
 int vc4_debugfs_init(struct drm_minor *minor);
diff --git a/include/drm/drm_irq.h b/include/drm/drm_irq.h
index 445406efb8dc..b489cc856e7a 100644
--- a/include/drm/drm_irq.h
+++ b/include/drm/drm_irq.h
@@ -121,6 +121,18 @@ struct drm_vblank_crtc {
 	 * drm_calc_timestamping_constants().
 	 */
 	int linedur_ns;
+
+	/**
+	 * @hwmode:
+	 *
+	 * Cache of the current hardware display mode. Only valide when @enabled
+	 * is set. This is used by helpers like
+	 * drm_calc_vbltimestamp_from_scanoutpos(). We can't just access the
+	 * hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode,
+	 * because that one is really hard to get at from interrupt context.
+	 */
+	struct drm_display_mode hwmode;
+
 	/**
 	 * @enabled: Tracks the enabling state of the corresponding &drm_crtc to
 	 * avoid double-disabling and hence corrupting saved state. Needed by
@@ -156,8 +168,7 @@ u32 drm_accurate_vblank_count(struct drm_crtc *crtc);
 bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
 					   unsigned int pipe, int *max_error,
 					   struct timeval *vblank_time,
-					   bool in_vblank_irq,
-					   const struct drm_display_mode *mode);
+					   bool in_vblank_irq);
 void drm_calc_timestamping_constants(struct drm_crtc *crtc,
 				     const struct drm_display_mode *mode);
 
-- 
2.11.0