[Intel-gfx] [PATCH 4/6] drm/i915: Allow mmio updates on all platforms.

[Maarten Lankhorst]

Op 23-03-16 om 16:07 schreef Ville Syrjälä:
> On Wed, Mar 23, 2016 at 02:24:30PM +0100, Maarten Lankhorst wrote:
>> Rename intel_unpin_work to intel_flip_work and use it for mmio flips
>> and unpinning. Use flip_queued_req to hold the wait request in the
>> mmio case and allow the vblank interrupt to complete mmio work to
>> have mmio flips run correctly on g4 and earlier.
> Before you actually go and trust drm_vblank_count() you should make it
> race free.

How about adding the below to the patch?

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index befac649aa96..05ec832e02de 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -11224,12 +11224,11 @@ static void intel_mmio_flip_work_func(struct work_struct *w)
 							    false, false,
 							    MAX_SCHEDULE_TIMEOUT) < 0);
 
-	intel_pipe_update_start(crtc);
+	intel_pipe_update_start(crtc, work);
 	primary->update_plane(&primary->base,
 			      crtc->config,
 			      to_intel_plane_state(primary->base.state));
-	atomic_set(&work->pending, INTEL_FLIP_PENDING);
-	intel_pipe_update_end(crtc);
+	intel_pipe_update_end(crtc, work);
 }
 
 static int intel_default_queue_flip(struct drm_device *dev,
@@ -13800,7 +13799,7 @@ static void intel_begin_crtc_commit(struct drm_crtc *crtc,
 	bool modeset = needs_modeset(crtc->state);
 
 	/* Perform vblank evasion around commit operation */
-	intel_pipe_update_start(intel_crtc);
+	intel_pipe_update_start(intel_crtc, NULL);
 
 	if (modeset)
 		return;
@@ -13816,7 +13815,7 @@ static void intel_finish_crtc_commit(struct drm_crtc *crtc,
 {
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 
-	intel_pipe_update_end(intel_crtc);
+	intel_pipe_update_end(intel_crtc, NULL);
 }
 
 /**
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index cac368138764..86d486cfd778 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1604,8 +1604,8 @@ bool intel_sdvo_init(struct drm_device *dev,
 int intel_plane_init(struct drm_device *dev, enum pipe pipe, int plane);
 int intel_sprite_set_colorkey(struct drm_device *dev, void *data,
 			      struct drm_file *file_priv);
-void intel_pipe_update_start(struct intel_crtc *crtc);
-void intel_pipe_update_end(struct intel_crtc *crtc);
+void intel_pipe_update_start(struct intel_crtc *crtc, struct intel_flip_work *work);
+void intel_pipe_update_end(struct intel_crtc *crtc, struct intel_flip_work *work);
 
 /* intel_tv.c */
 void intel_tv_init(struct drm_device *dev);
diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c
index 8821533561b1..8da59a1eca56 100644
--- a/drivers/gpu/drm/i915/intel_sprite.c
+++ b/drivers/gpu/drm/i915/intel_sprite.c
@@ -78,7 +78,8 @@ static int usecs_to_scanlines(const struct drm_display_mode *adjusted_mode,
  * avoid random delays. The value written to @start_vbl_count should be
  * supplied to intel_pipe_update_end() for error checking.
  */
-void intel_pipe_update_start(struct intel_crtc *crtc)
+void intel_pipe_update_start(struct intel_crtc *crtc,
+			     struct intel_flip_work *work)
 {
 	struct drm_device *dev = crtc->base.dev;
 	const struct drm_display_mode *adjusted_mode = &crtc->config->base.adjusted_mode;
@@ -142,6 +143,9 @@ void intel_pipe_update_start(struct intel_crtc *crtc)
 	crtc->debug.start_vbl_count =
 		dev->driver->get_vblank_counter(dev, pipe);
 
+	if (work)
+		work->flip_queued_vblank = crtc->debug.start_vbl_count;
+
 	trace_i915_pipe_update_vblank_evaded(crtc);
 }
 
@@ -154,7 +158,7 @@ void intel_pipe_update_start(struct intel_crtc *crtc)
  * re-enables interrupts and verifies the update was actually completed
  * before a vblank using the value of @start_vbl_count.
  */
-void intel_pipe_update_end(struct intel_crtc *crtc)
+void intel_pipe_update_end(struct intel_crtc *crtc, struct intel_flip_work *work)
 {
 	struct drm_device *dev = crtc->base.dev;
 	enum pipe pipe = crtc->pipe;
@@ -162,6 +166,12 @@ void intel_pipe_update_end(struct intel_crtc *crtc)
 	u32 end_vbl_count = dev->driver->get_vblank_counter(dev, pipe);
 	ktime_t end_vbl_time = ktime_get();
 
+	if (work) {
+		work->flip_queued_vblank = end_vbl_count;
+		smp_mb__before_atomic();
+		atomic_set(&work->pending, INTEL_FLIP_PENDING);
+	}
+
 	trace_i915_pipe_update_end(crtc, end_vbl_count, scanline_end);
 
 	local_irq_enable();