Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit f326038a authored by Daniel Vetter's avatar Daniel Vetter
Browse files

drm/i915: Clarify event_lock locking, irq&mixed context 



Now we tackle the functions also called from interrupt handlers.

- intel_check_page_flip is exclusively called from irq handlers, so a
  plain spin_lock is all we need. In i915_irq.c we have the convention
  to give all such functions an _irq_handler postfix, but that would
  look strange and als be a bit a misleading name. I've opted for a
  WARN_ON(!in_irq()) instead.

- The other two places left are called both from interrupt handlers
  and from our reset work, so need the full irqsave dance. Annotate
  them with a short comment.

Reviewed-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 5e2d7afc

drivers/gpu/drm/i915/intel_display.c

+14 −4
Original line number Diff line number Diff line
@@ -9328,6 +9328,10 @@ static void do_intel_finish_page_flip(struct drm_device *dev, 
	if (intel_crtc == NULL)

		return;



	/*

	 * This is called both by irq handlers and the reset code (to complete

	 * lost pageflips) so needs the full irqsave spinlocks.

	 */

	spin_lock_irqsave(&dev->event_lock, flags);

	work = intel_crtc->unpin_work;
@@ -9409,7 +9413,12 @@ void intel_prepare_page_flip(struct drm_device *dev, int plane) 
		to_intel_crtc(dev_priv->plane_to_crtc_mapping[plane]);

	unsigned long flags;



	/* NB: An MMIO update of the plane base pointer will also



	/*

	 * This is called both by irq handlers and the reset code (to complete

	 * lost pageflips) so needs the full irqsave spinlocks.

	 *

	 * NB: An MMIO update of the plane base pointer will also

	 * generate a page-flip completion irq, i.e. every modeset

	 * is also accompanied by a spurious intel_prepare_page_flip().

	 */
@@ -9866,18 +9875,19 @@ void intel_check_page_flip(struct drm_device *dev, int pipe) 
	struct drm_i915_private *dev_priv = dev->dev_private;

	struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe];

	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);

	unsigned long flags;



	WARN_ON(!in_irq());



	if (crtc == NULL)

		return;



	spin_lock_irqsave(&dev->event_lock, flags);

	spin_lock(&dev->event_lock);

	if (intel_crtc->unpin_work && __intel_pageflip_stall_check(dev, crtc)) {

		WARN_ONCE(1, "Kicking stuck page flip: queued at %d, now %d\n",

			 intel_crtc->unpin_work->flip_queued_vblank, drm_vblank_count(dev, pipe));

		page_flip_completed(intel_crtc);

	}

	spin_unlock_irqrestore(&dev->event_lock, flags);

	spin_unlock(&dev->event_lock);

}



static int intel_crtc_page_flip(struct drm_crtc *crtc,