Bug#948568: nvidia-graphics-drivers: screen tearing with Linux 5.4 due to loss of "PRIME Synchronization"

[Luca Boccassi]

On Fri, 10 Jan 2020 at 13:21, Andreas Beckmann <anbe at debian.org> wrote:
>
> Control: tag -1 upstream
> Control: forwarded -1
> https://devtalk.nvidia.com/default/topic/1068045/linux/5-4-kernel-breaks-prime-synchronization-/
>
> On 10/01/2020 10.37, Raphaël Hertzog wrote:
> > We had multiple reports of nvidia users having refresh issues ever since
> > they switched to Linux 5.4.
> >
> > I believe they are affected by the loss of "PRIME synchronization" as
> > explained in https://devtalk.nvidia.com/default/topic/1068045/linux/5-4-kernel-breaks-prime-synchronization-/
>
> Luca, can you reproduce something like that?
>
> > There's a patch for 440.44 in that thread but I don't know of any upstream
> > fix. Direct link to patch: https://gitlab.com/snippets/1927096
>
> That patch looks like a crude hack. I have no clue what its intention
> is. The only thing I understood for sure is that it abuses the
> NV_DRM_DRIVER_HAS_GEM_PRIME_RES_OBJ condition, probably by turning it
> into "true". It's also not backwards compatible.
> I'm not going to apply it in the current shape. :-(
>
>
> Andreas

Hi,

I can reproduce, but I agree with you on the review of the patch, it
doesn't look very clean. Given it only affects 5.4 it might be fine to
wait for an upstream fix?