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authorChris Wilson <chris@chris-wilson.co.uk>2017-08-04 09:23:28 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-05-31 06:43:58 -0700
commitd1ea5230de62b845f0af46a2939294bf85e49a7b (patch)
tree4d92be306267141cda6b38c1d2e798361554f1f7
parentaa5a0c0b0bb2e9563da7915b4cae2546c176b318 (diff)
drm: Wake up next in drm_read() chain if we are forced to putback the event
[ Upstream commit 60b801999c48b6c1dd04e653a38e2e613664264e ] After an event is sent, we try to copy it into the user buffer of the first waiter in drm_read() and if the user buffer doesn't have enough room we put it back onto the list. However, we didn't wake up any subsequent waiter, so that event may sit on the list until either a new vblank event is sent or a new waiter appears. Rare, but in the worst case may lead to a stuck process. Testcase: igt/drm_read/short-buffer-wakeup Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20170804082328.17173-1-chris@chris-wilson.co.uk Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r--drivers/gpu/drm/drm_file.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
index 7caa3c7ed978..9701469a6e93 100644
--- a/drivers/gpu/drm/drm_file.c
+++ b/drivers/gpu/drm/drm_file.c
@@ -577,6 +577,7 @@ put_back_event:
file_priv->event_space -= length;
list_add(&e->link, &file_priv->event_list);
spin_unlock_irq(&dev->event_lock);
+ wake_up_interruptible(&file_priv->event_wait);
break;
}