On Sat, May 15, 2021 at 10:12 AM Richard Dietrich Wachler rwachler@posteo.net wrote:
Excuse my novicesness,
i use 2 RX460 on a KGPE-D16 server board to drive 4 displays.
02:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Baffin [Radeon RX 460/560D / Pro 450/455/460/555/555X/560/560X] (rev cf) 06:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Baffin [Radeon RX 460/560D / Pro 450/455/460/555/555X/560/560X] (rev cf)
There is a noticeable mouse lag on the second card, so i investigated and got logspam 20 times a second like this:
May 15 15:58:27 xx kernel: amdgpu 0000:02:00.0: cannot be used for peer-to-peer DMA as the client and provider (0000:06:00.0) do not share an upstream bridge or whitelisted host bridge
It seems there is no real way to disable the check or disable P2P DMA completely. Or maybe my problem is elsewhere?
Thanks for any hints, i havent found anything about this as its quite a new feature.
Fixed in this patch: https://patchwork.kernel.org/project/dri-devel/patch/20210517115705.2141-1-c...
Alex