On Tue, Oct 18, 2016 at 01:47:24AM +0200, Mario Kleiner wrote:
> On 10/18/2016 12:13 AM, Arnd Bergmann wrote:
> > gcc warns about the timestamp in drm_wait_vblank being possibly
> > used without an initialization:
> > 
> > drivers/gpu/drm/drm_irq.c: In function 'drm_crtc_send_vblank_event':
> > drivers/gpu/drm/drm_irq.c:992:24: error: 'now.tv_usec' may be used 
> > uninitialized in this function [-Werror=maybe-uninitialized]
> > drivers/gpu/drm/drm_irq.c:1069:17: note: 'now.tv_usec' was declared here
> > drivers/gpu/drm/drm_irq.c:991:23: error: 'now.tv_sec' may be used 
> > uninitialized in this function [-Werror=maybe-uninitialized]
> > 
> > This can happen if drm_vblank_count_and_time() returns 0 in its
> > error path. To sanitize the error case, I'm changing that function
> > to return a zero timestamp when it fails.
> > 
> > Fixes: e6ae8687a87b ("drm: idiot-proof vblank")
> > Reviewed-by: David Herrmann <dh.herrm...@gmail.com>
> > Cc: Rob Clark <robdcl...@gmail.com>
> > Cc: Daniel Vetter <daniel.vet...@ffwll.ch>
> > Signed-off-by: Arnd Bergmann <a...@arndb.de>
> > ---
> > First submitted in January 2016, second submission in February,
> > the patch is still required.

Hm, sorry I missed that.

> >  drivers/gpu/drm/drm_irq.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
> > index b969a64..48a6167 100644
> > --- a/drivers/gpu/drm/drm_irq.c
> > +++ b/drivers/gpu/drm/drm_irq.c
> > @@ -952,8 +952,10 @@ static u32 drm_vblank_count_and_time(struct drm_device 
> > *dev, unsigned int pipe,
> >     u32 vblank_count;
> >     unsigned int seq;
> > 
> > -   if (WARN_ON(pipe >= dev->num_crtcs))
> > +   if (WARN_ON(pipe >= dev->num_crtcs)) {
> > +           *vblanktime = (struct timeval) { 0 };
> >             return 0;
> > +   }
> > 
> >     do {
> >             seq = read_seqbegin(&vblank->seqlock);
> > 
> 
> Looks good to me.
> 
> Reviewed-by: Mario Kleiner <mario.kleiner...@gmail.com>

Applied to drm-misc, thanks.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

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