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* [PATCH 1/4] drm/irq: Add drm_crtc_vblank_reset
@ 2015-02-03 10:30 Daniel Vetter
  2015-02-03 10:30 ` [PATCH 2/4] drm/i915: Drop pipe_enable checks in vblank funcs Daniel Vetter
                   ` (5 more replies)
  0 siblings, 6 replies; 19+ messages in thread
From: Daniel Vetter @ 2015-02-03 10:30 UTC (permalink / raw)
  To: Intel Graphics Development
  Cc: Daniel Vetter, Laurent Pinchart, DRI Development, Daniel Vetter

At driver load we need to tell the vblank code about the state of the
pipes, so that the logic around reject vblank_get when the pipe is off
works correctly.

Thus far i915 used drm_vblank_off, but one of the side-effects of it
is that it also saves the vblank counter. And for that it calls down
into the ->get_vblank_counter hook. Which isn't really a good idea
when the pipe is off for a few reasons:
- With runtime pm the register might not respond.
- If the pipe is off some datastructures might not be around or
  unitialized.

The later is what blew up on gen3: We look at intel_crtc->config to
compute the vblank counter, and for a disabled pipe at boot-up that's
just not there. Thus far this was papered over by a check for
intel_crtc->active, but I want to get rid of that (since it's fairly
race, vblank hooks are called from all kinds of places).

So prep for that by adding a _reset functions which only does what we
really need to be done at driver load: Mark the vblank pipe as off,
but don't do any vblank counter saving or event flushing - neither of
that is required.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
 drivers/gpu/drm/drm_irq.c            | 32 ++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_display.c |  4 ++--
 include/drm/drmP.h                   |  1 +
 3 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 75647e7f012b..1e5fb1b994d7 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -1226,6 +1226,38 @@ void drm_crtc_vblank_off(struct drm_crtc *crtc)
 EXPORT_SYMBOL(drm_crtc_vblank_off);
 
 /**
+ * drm_crtc_vblank_reset - reset vblank state to off on a CRTC
+ * @crtc: CRTC in question
+ *
+ * Drivers can use this function to reset the vblank state to off at load time.
+ * Drivers should use this together with the drm_crtc_vblank_off() and
+ * drm_crtc_vblank_on() functions. The diffrence comparet to
+ * drm_crtc_vblank_off() is that this function doesn't save the vblank counter
+ * and hence doesn't need to call any driver hooks.
+ */
+void drm_crtc_vblank_reset(struct drm_crtc *drm_crtc)
+{
+	struct drm_device *dev = drm_crtc->dev;
+	unsigned long irqflags;
+	int crtc = drm_crtc_index(drm_crtc);
+	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
+
+	spin_lock_irqsave(&dev->vbl_lock, irqflags);
+	/*
+	 * Prevent subsequent drm_vblank_get() from enabling the vblank
+	 * interrupt by bumping the refcount.
+	 */
+	if (!vblank->inmodeset) {
+		atomic_inc(&vblank->refcount);
+		vblank->inmodeset = 1;
+	}
+	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
+
+	WARN_ON(!list_empty(&dev->vblank_event_list));
+}
+EXPORT_SYMBOL(drm_crtc_vblank_reset);
+
+/**
  * drm_vblank_on - enable vblank events on a CRTC
  * @dev: DRM device
  * @crtc: CRTC in question
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 423ef959264d..f8871a184747 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -13296,9 +13296,9 @@ static void intel_sanitize_crtc(struct intel_crtc *crtc)
 	/* restore vblank interrupts to correct state */
 	if (crtc->active) {
 		update_scanline_offset(crtc);
-		drm_vblank_on(dev, crtc->pipe);
+		drm_crtc_vblank_on(&crtc->base);
 	} else
-		drm_vblank_off(dev, crtc->pipe);
+		drm_crtc_vblank_reset(&crtc->base);
 
 	/* We need to sanitize the plane -> pipe mapping first because this will
 	 * disable the crtc (and hence change the state) if it is wrong. Note
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index e928625a9da0..54c6ea1e5866 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -922,6 +922,7 @@ extern void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
 extern void drm_vblank_off(struct drm_device *dev, int crtc);
 extern void drm_vblank_on(struct drm_device *dev, int crtc);
 extern void drm_crtc_vblank_off(struct drm_crtc *crtc);
+extern void drm_crtc_vblank_reset(struct drm_crtc *crtc);
 extern void drm_crtc_vblank_on(struct drm_crtc *crtc);
 extern void drm_vblank_cleanup(struct drm_device *dev);
 
-- 
1.9.3

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^ permalink raw reply related	[flat|nested] 19+ messages in thread

end of thread, other threads:[~2015-02-23 11:32 UTC | newest]

Thread overview: 19+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-02-03 10:30 [PATCH 1/4] drm/irq: Add drm_crtc_vblank_reset Daniel Vetter
2015-02-03 10:30 ` [PATCH 2/4] drm/i915: Drop pipe_enable checks in vblank funcs Daniel Vetter
2015-02-12 22:37   ` Imre Deak
2015-02-13  7:39     ` Daniel Vetter
2015-02-03 10:30 ` [PATCH 3/4] drm/i915: Flatten DRIVER_MODESET checks in i915_irq.c Daniel Vetter
2015-02-12 22:38   ` Imre Deak
2015-02-19 12:25     ` Dave Gordon
2015-02-19 13:39       ` Imre Deak
2015-02-19 13:42         ` Imre Deak
2015-02-23 11:32           ` [Intel-gfx] " Imre Deak
2015-02-03 10:30 ` [PATCH 4/4] drm/i915: Switch to drm_crtc variants of vblank functions Daniel Vetter
2015-02-12 22:57   ` Imre Deak
2015-02-13  7:46     ` [Intel-gfx] " Daniel Vetter
2015-02-03 11:31 ` [PATCH 1/4] drm/irq: Add drm_crtc_vblank_reset Laurent Pinchart
2015-02-03 11:53   ` Daniel Vetter
2015-02-04  9:31 ` [Intel-gfx] " Ville Syrjälä
2015-02-12 21:56 ` Imre Deak
2015-02-13  7:44   ` Daniel Vetter
2015-02-13 11:35     ` Imre Deak

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