Re: [PATCH 3/3] dma-buf: Check status of enable-signaling bit on debug

[Christian König]

Am 29.09.22 um 20:30 schrieb Yadav, Arvind:
> On 9/29/2022 11:48 PM, Christian König wrote:
> > Am 27.09.22 um 19:24 schrieb Arvind Yadav:
> > > Fence signaling must be enabled to make sure that
> > > the dma_fence_is_signaled_locked() function ever returns true.
> > > Since drivers and implementations sometimes mess this up,
> > > this ensures correct behaviour when DMABUF_DEBUG_ENABLE_SIGNALING
> > > is used during debugging.
> > > This should make any implementation bugs resulting in not
> > > signaled fences much more obvious.
> >
> > Are all IGT tests now passing with this? That would be a bit 
> > unfortunate because it means we still have missed the bug in 
> > drm_syncobj.
> IGT has these test cases related to syncobj (syncobj_basic, 
> syncobj_timeline and syncobj_wait)and all are passing.
>
> I will check syncobj and let you know.

Maybe CC the Intel list and let their CI systems take a look. That's 
usually rather valuable.

Thanks,
Christian.

> ~Arvind
>
> > Christian.
> >
> > > Signed-off-by: Arvind Yadav <Arvind.Yadav@xxxxxxx>
> > > ---
> > >   include/linux/dma-fence.h | 5 +++++
> > >   1 file changed, 5 insertions(+)
> > >
> > > diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h
> > > index 775cdc0b4f24..5156dc6be0a6 100644
> > > --- a/include/linux/dma-fence.h
> > > +++ b/include/linux/dma-fence.h
> > > @@ -398,6 +398,11 @@ void dma_fence_enable_sw_signaling(struct 
> > > dma_fence *fence);
> > >   static inline bool
> > >   dma_fence_is_signaled_locked(struct dma_fence *fence)
> > >   {
> > > +#ifdef CONFIG_DMABUF_DEBUG_ENABLE_SIGNALING
> > > +    if (!test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &fence->flags))
> > > +        return false;
> > > +#endif
> > > +
> > >       if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
> > >           return true;