drm/i915: wake up all pageflip waiters

Otherwise it seems like we can get stuck with concurrent waiters.
Right now this /shouldn't/ be a problem, since all pending pageflip
waiters are serialized by the one mode_config.mutex, so there's at
most on waiter. But better paranoid than sorry, since this is tricky
code.

v2: WARN_ON(waitqueue_active) before waiting, as suggested by Chris
Wilson.

Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 8c36a11a9a57..40b6b5e9d6ef 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2220,6 +2220,8 @@ intel_finish_fb(struct drm_framebuffer *old_fb)
         bool was_interruptible = dev_priv->mm.interruptible;
         int ret;
 
+        WARN_ON(waitqueue_active(&dev_priv->pending_flip_queue));
+
         wait_event(dev_priv->pending_flip_queue,
                    atomic_read(&dev_priv->mm.wedged) ||
                    atomic_read(&obj->pending_flip) == 0);
@@ -2887,6 +2889,8 @@ static void intel_crtc_wait_for_pending_flips(struct drm_crtc *crtc)
         if (crtc->fb == NULL)
                 return;
 
+        WARN_ON(waitqueue_active(&dev_priv->pending_flip_queue));
+
         wait_event(dev_priv->pending_flip_queue,
                    !intel_crtc_has_pending_flip(crtc));
 
@@ -6824,7 +6828,7 @@ static void do_intel_finish_page_flip(struct drm_device *dev,
 
         obj = work->old_fb_obj;
 
-        wake_up(&dev_priv->pending_flip_queue);
+        wake_up_all(&dev_priv->pending_flip_queue);
 
         queue_work(dev_priv->wq, &work->work);