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Commit 5e2d7afc authored by Daniel Vetter's avatar Daniel Vetter
Browse files

drm/i915: Clarify event_lock locking, process context 



It's good practice to use the more specific versions for irq save
spinlocks both as executable documentation and to enforce saner
design. The _irqsave version really should only be used if the calling
context is unknown and there's a good reason to call a function from
all kinds of places.

This is the first step whice replaces all occurances of _irqsave in
process context with the simpler irq disable/enable variants. We don't
have any funky spinlock nesting going on, especially since the
event_lock is the outermost of the irq/vblank related spinlocks.

Reviewed-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 4b3a9526

drivers/gpu/drm/i915/i915_debugfs.c

+2 −3
Original line number Diff line number Diff line
@@ -516,7 +516,6 @@ static int i915_gem_pageflip_info(struct seq_file *m, void *data) 
	struct drm_info_node *node = m->private;

	struct drm_device *dev = node->minor->dev;

	struct drm_i915_private *dev_priv = dev->dev_private;

	unsigned long flags;

	struct intel_crtc *crtc;

	int ret;
@@ -529,7 +528,7 @@ static int i915_gem_pageflip_info(struct seq_file *m, void *data) 
		const char plane = plane_name(crtc->plane);

		struct intel_unpin_work *work;



		spin_lock_irqsave(&dev->event_lock, flags);

		spin_lock_irq(&dev->event_lock);

		work = crtc->unpin_work;

		if (work == NULL) {

			seq_printf(m, "No flip due on pipe %c (plane %c)\n",
@@ -575,7 +574,7 @@ static int i915_gem_pageflip_info(struct seq_file *m, void *data) 
				seq_printf(m, "MMIO update completed? %d\n",  addr == work->gtt_offset);

			}

		}

		spin_unlock_irqrestore(&dev->event_lock, flags);

		spin_unlock_irq(&dev->event_lock);

	}



	mutex_unlock(&dev->struct_mutex);

drivers/gpu/drm/i915/intel_display.c

+15 −20
Original line number Diff line number Diff line
@@ -2711,16 +2711,15 @@ static bool intel_crtc_has_pending_flip(struct drm_crtc *crtc) 
	struct drm_device *dev = crtc->dev;

	struct drm_i915_private *dev_priv = dev->dev_private;

	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);

	unsigned long flags;

	bool pending;



	if (i915_reset_in_progress(&dev_priv->gpu_error) ||

	    intel_crtc->reset_counter != atomic_read(&dev_priv->gpu_error.reset_counter))

		return false;



	spin_lock_irqsave(&dev->event_lock, flags);

	spin_lock_irq(&dev->event_lock);

	pending = to_intel_crtc(crtc)->unpin_work != NULL;

	spin_unlock_irqrestore(&dev->event_lock, flags);

	spin_unlock_irq(&dev->event_lock);



	return pending;

}
@@ -3431,14 +3430,13 @@ void intel_crtc_wait_for_pending_flips(struct drm_crtc *crtc) 
				       !intel_crtc_has_pending_flip(crtc),

				       60*HZ) == 0)) {

		struct intel_crtc *intel_crtc = to_intel_crtc(crtc);

		unsigned long flags;



		spin_lock_irqsave(&dev->event_lock, flags);

		spin_lock_irq(&dev->event_lock);

		if (intel_crtc->unpin_work) {

			WARN_ONCE(1, "Removing stuck page flip\n");

			page_flip_completed(intel_crtc);

		}

		spin_unlock_irqrestore(&dev->event_lock, flags);

		spin_unlock_irq(&dev->event_lock);

	}



	if (crtc->primary->fb) {
@@ -9280,12 +9278,11 @@ static void intel_crtc_destroy(struct drm_crtc *crtc) 
	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);

	struct drm_device *dev = crtc->dev;

	struct intel_unpin_work *work;

	unsigned long flags;



	spin_lock_irqsave(&dev->event_lock, flags);

	spin_lock_irq(&dev->event_lock);

	work = intel_crtc->unpin_work;

	intel_crtc->unpin_work = NULL;

	spin_unlock_irqrestore(&dev->event_lock, flags);

	spin_unlock_irq(&dev->event_lock);



	if (work) {

		cancel_work_sync(&work->work);
@@ -9896,7 +9893,6 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc, 
	enum pipe pipe = intel_crtc->pipe;

	struct intel_unpin_work *work;

	struct intel_engine_cs *ring;

	unsigned long flags;

	int ret;



	//trigger software GT busyness calculation
@@ -9940,7 +9936,7 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc, 
		goto free_work;



	/* We borrow the event spin lock for protecting unpin_work */

	spin_lock_irqsave(&dev->event_lock, flags);

	spin_lock_irq(&dev->event_lock);

	if (intel_crtc->unpin_work) {

		/* Before declaring the flip queue wedged, check if

		 * the hardware completed the operation behind our backs.
@@ -9950,7 +9946,7 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc, 
			page_flip_completed(intel_crtc);

		} else {

			DRM_DEBUG_DRIVER("flip queue: crtc already busy\n");

			spin_unlock_irqrestore(&dev->event_lock, flags);

			spin_unlock_irq(&dev->event_lock);



			drm_crtc_vblank_put(crtc);

			kfree(work);
@@ -9958,7 +9954,7 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc, 
		}

	}

	intel_crtc->unpin_work = work;

	spin_unlock_irqrestore(&dev->event_lock, flags);

	spin_unlock_irq(&dev->event_lock);



	if (atomic_read(&intel_crtc->unpin_work_count) >= 2)

		flush_workqueue(dev_priv->wq);
@@ -10045,9 +10041,9 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc, 
	mutex_unlock(&dev->struct_mutex);



cleanup:

	spin_lock_irqsave(&dev->event_lock, flags);

	spin_lock_irq(&dev->event_lock);

	intel_crtc->unpin_work = NULL;

	spin_unlock_irqrestore(&dev->event_lock, flags);

	spin_unlock_irq(&dev->event_lock);



	drm_crtc_vblank_put(crtc);

free_work:
@@ -10058,9 +10054,9 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc, 
		intel_crtc_wait_for_pending_flips(crtc);

		ret = intel_pipe_set_base(crtc, crtc->x, crtc->y, fb);

		if (ret == 0 && event) {

			spin_lock_irqsave(&dev->event_lock, flags);

			spin_lock_irq(&dev->event_lock);

			drm_send_vblank_event(dev, pipe, event);

			spin_unlock_irqrestore(&dev->event_lock, flags);

			spin_unlock_irq(&dev->event_lock);

		}

	}

	return ret;
@@ -13769,9 +13765,8 @@ void intel_modeset_preclose(struct drm_device *dev, struct drm_file *file) 


	for_each_intel_crtc(dev, crtc) {

		struct intel_unpin_work *work;

		unsigned long irqflags;



		spin_lock_irqsave(&dev->event_lock, irqflags);

		spin_lock_irq(&dev->event_lock);



		work = crtc->unpin_work;
@@ -13781,6 +13776,6 @@ void intel_modeset_preclose(struct drm_device *dev, struct drm_file *file) 
			work->event = NULL;

		}



		spin_unlock_irqrestore(&dev->event_lock, irqflags);

		spin_unlock_irq(&dev->event_lock);

	}

}