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

[Andreas Beckmann]

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