| Message ID | 1456864277-9551-1-git-send-email-mario.kleiner.de@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 02.03.2016 05:31, Mario Kleiner wrote: > 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. > > Reported-by: Dan Carpenter <dan.carpenter@oracle.com> > Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com> > Cc: <stable@vger.kernel.org> # 4.4+ > Cc: Michel Dänzer <michel.daenzer@amd.com> > Cc: Alex Deucher <alexander.deucher@amd.com> Both patches are Reviewed-by: Michel Dänzer <michel.daenzer@amd.com> Alex, these should go into 4.5 if at all possible.
On Sat, Mar 5, 2016 at 3:00 AM, Michel Dänzer <michel@daenzer.net> wrote: > On 02.03.2016 05:31, Mario Kleiner wrote: >> 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. >> >> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> >> Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com> >> Cc: <stable@vger.kernel.org> # 4.4+ >> Cc: Michel Dänzer <michel.daenzer@amd.com> >> Cc: Alex Deucher <alexander.deucher@amd.com> > > Both patches are > > Reviewed-by: Michel Dänzer <michel.daenzer@amd.com> > > > Alex, these should go into 4.5 if at all possible. Yup, Added to my 4.5 fixes tree. Alex
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c index 8297bc3..1846d65 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); };
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. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com> Cc: <stable@vger.kernel.org> # 4.4+ Cc: Michel Dänzer <michel.daenzer@amd.com> Cc: Alex Deucher <alexander.deucher@amd.com> --- drivers/gpu/drm/amd/amdgpu/amdgpu_display.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)