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| author | Mario Kleiner <mario.kleiner.de@gmail.com> | 2016-03-01 21:31:16 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-03-16 08:43:00 -0700 |
| commit | 0f36e5ab227c3ca8770fddc5596a024176de0852 (patch) | |
| tree | 20104532024baa84da646ca426c10ef5739c61db | |
| parent | 6f0679556b563bcd3d433d5781454123f1d134c5 (diff) | |
| download | linux-stable-0f36e5ab227c3ca8770fddc5596a024176de0852.tar.gz linux-stable-0f36e5ab227c3ca8770fddc5596a024176de0852.tar.bz2 linux-stable-0f36e5ab227c3ca8770fddc5596a024176de0852.zip | |
drm/amdgpu: Fix error handling in amdgpu_flip_work_func.
commit 90e94b160c7f647ddffda707f5e3c0c66c170df8 upstream.
The patch e1d09dc0ccc6: "drm/amdgpu: Don't hang in
amdgpu_flip_work_func on disabled crtc." from Feb 19, 2016, leads to
the following static checker warning, as reported by Dan Carpenter in
https://lists.freedesktop.org/archives/dri-devel/2016-February/101987.html
drivers/gpu/drm/amd/amdgpu/amdgpu_display.c:127 amdgpu_flip_work_func() warn: should this be 'repcnt == -1'
drivers/gpu/drm/amd/amdgpu/amdgpu_display.c:136 amdgpu_flip_work_func() error: double unlock 'spin_lock:&crtc->dev->event_lock'
drivers/gpu/drm/amd/amdgpu/amdgpu_display.c:136 amdgpu_flip_work_func() error: double unlock 'irqsave:flags'
This patch fixes both reported problems:
Change post-decrement of repcnt to pre-decrement, so
it can't underflow anymore, but still performs up to
three repetitions - three is the maximum one could
expect in practice.
Move the spin_unlock_irqrestore to where it actually
belongs.
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Cc: Michel Dänzer <michel.daenzer@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/gpu/drm/amd/amdgpu/amdgpu_display.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c index 0c713a908304..82903ca78529 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c @@ -96,7 +96,7 @@ static void amdgpu_flip_work_func(struct work_struct *__work) * In practice this won't execute very often unless on very fast * machines because the time window for this to happen is very small. */ - while (amdgpuCrtc->enabled && repcnt--) { + while (amdgpuCrtc->enabled && --repcnt) { /* GET_DISTANCE_TO_VBLANKSTART returns distance to real vblank * start in hpos, and to the "fudged earlier" vblank start in * vpos. @@ -112,13 +112,13 @@ static void amdgpu_flip_work_func(struct work_struct *__work) break; /* Sleep at least until estimated real start of hw vblank */ - spin_unlock_irqrestore(&crtc->dev->event_lock, flags); min_udelay = (-hpos + 1) * max(vblank->linedur_ns / 1000, 5); if (min_udelay > vblank->framedur_ns / 2000) { /* Don't wait ridiculously long - something is wrong */ repcnt = 0; break; } + spin_unlock_irqrestore(&crtc->dev->event_lock, flags); usleep_range(min_udelay, 2 * min_udelay); spin_lock_irqsave(&crtc->dev->event_lock, flags); }; |