[Intel-gfx] [PATCH 1/5] drm/vblank: Fix return type for drm_vblank_count()

[Pandiyan, Dhinakaran]

On Thu, 2018-01-18 at 23:36 -0800, Rodrigo Vivi wrote:
> On Fri, Jan 12, 2018 at 09:57:03PM +0000, Dhinakaran Pandiyan wrote:
> > drm_vblank_count() has a u32 type returning what is a 64-bit vblank count.
> > The effect of this is when drm_wait_vblank_ioctl() tries to widen the user
> > space requested vblank sequence using this clipped 32-bit count(when the
> > value is >= 2^32) as reference, the requested sequence remains a 32-bit
> > value and gets queued like that. However, the code that checks if the
> > requested sequence has passed compares this against the 64-bit vblank
> > count.
> 
> Worth to mention and probably
> Fixes: 570e86963a51 ("drm: Widen vblank count to 64-bits [v3]")
> 
> btw, I spotted at least one more place even with the series applied.
> 32 current_vblank; at drm_mode_page_flip_ioctl...
> 

There seem to be several such callers for drm_crtc_vblank_count(). I can
fix it up as a follow-up series.

> so, probably worth to do a deeper check down to all paths...
> 
> anayway, for this patch:
> Reviewed-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> 
> > 
> > Cc: Keith Packard <keithp at keithp.com>
> > Cc: Michel Dänzer <michel at daenzer.net>
> > Cc: Daniel Vetter <daniel at ffwll.ch>
> > Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
> > ---
> >  drivers/gpu/drm/drm_vblank.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
> > index 32d9bcf5be7f..768a8e44d99b 100644
> > --- a/drivers/gpu/drm/drm_vblank.c
> > +++ b/drivers/gpu/drm/drm_vblank.c
> > @@ -271,7 +271,7 @@ static void drm_update_vblank_count(struct drm_device *dev, unsigned int pipe,
> >  	store_vblank(dev, pipe, diff, t_vblank, cur_vblank);
> >  }
> >  
> > -static u32 drm_vblank_count(struct drm_device *dev, unsigned int pipe)
> > +static u64 drm_vblank_count(struct drm_device *dev, unsigned int pipe)
> >  {
> >  	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> >  
> > -- 
> > 2.11.0
> > 
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