TTM Multihop + Intel Keem Bay Display Support Queued For Linux 5.11

[phoronix]

Phoronix: TTM Multihop + Intel Keem Bay Display Support Queued For Linux 5.11

The Translation Table Maps (TTM) video memory management code used within the Linux kernel by DRM drivers such as Nouveau and Radeon/AMDGPU is seeing some improvements with the forthcoming Linux 5.11 kernel cycle...

http://www.phoronix.com/scan.php?page=news_item&px=TTM-Multihop-For-Linux-5.11

[treba]

airlied I'd like to ask you about one potentially important use-case for this: Mutter/Gnome-Shell does support DMAbuf sharing for screen recording on Wayland as of Gnome 3.38. It's currently disabled for non-Intel as it turned out to be slower than the simple glreadpixel solution. Do you think (or have you maybe even tested) if this situation improves with these patches? The new screen recording performs really good and it would be great to see it enabled for a bigger share of drivers.

[MrCooper]

airlied I'd like to ask you about one potentially important use-case for this: Mutter/Gnome-Shell does support DMAbuf sharing for screen recording on Wayland as of Gnome 3.38. It's currently disabled for non-Intel as it turned out to be slower than the simple glreadpixel solution. Do you think (or have you maybe even tested) if this situation improves with these patches?

Unfortunately not. The problem is consumers which read the buffer contents directly via CPU mappings. Nothing the kernel or mutter can do about it. (Well, the kernel could withdraw mmap support for dma-buf fds in theory, but it’s unlikely to happen due to the „no user-space regressions“ rule).

[Guest]

airlied I'd like to ask you about one potentially important use-case for this: Mutter/Gnome-Shell does support DMAbuf sharing for screen recording on Wayland as of Gnome 3.38. It's currently disabled for non-Intel as it turned out to be slower than the simple glreadpixel solution. Do you think (or have you maybe even tested) if this situation improves with these patches? The new screen recording performs really good and it would be great to see it enabled for a bigger share of drivers.

What about AMD iGPUs? Is it slow there as well? Is it mainly a problem on systems with dGPU?