RX 5500 XT hangs kernel on boot

[Alex Deucher]

On Mon, Jan 6, 2020 at 11:59 PM Arvid Brodin <arvidb at fripost.org> wrote:
>
> Hi,
>
> So I tried to use my RX 5500 XT for the first time today. Kernel updated to 5.4.8, fresh navi14 firmware files fetched from the linux-firmware repo, and of course power cable connected to the card.
>
> Booting the kernel hangs when the graphics are initialized (on two different OS:es: Ubuntu 18.04 and Gentoo, Ubuntu with linux-5.4.7 and firmware updated today, Gentoo with 5.4.8 and firmware from 2019-12-15). There's nothing on the screen except sometimes a non-blinking cursor - I get no error messages.
>
> So I tried to boot with the iGPU as primary with the RX 5500 XT still in the box. This works, the card is detected by the kernel, firmware loads etc, and it shows up in xrandr. But when enabling the output (something like 'xrandr --output DisplayPort-1-2 --preferred --same-as HDMI-1') the computer "half-freezes", as in, I get a little bit of reaction every 10 seconds or so - caps lock change, a kernel log line is printed, etc. Mouse cursor moves but system does not react to clicks.
>
> Kernel logs at this time looks like this (copied by hand from photo):
>
> kernel: [drm:amdgpu_dm_commit_planes.constprop.0 [amdgpu]] *ERROR* Waiting for fences timed out!
> kernel: Asynchronous wait on fence drm_sched:gfx_0.0.0:11 timed out (hint:submit_notify+0x0/0x80 [i915])
> kernel: [drm:amdgpu_dm_commit_planes.constprop.0 [amdgpu]] *ERROR* Waiting for fences timed out!
> kernel: Asynchronous wait on fence drm_sched:gfx_0.0.0:12 timed out (hint:submit_notify+0x0/0x80 [i915])
>
> etc... (a new pair of lines appear about every 11 seconds).
>
> I also get noise/nonsense output on the RX 5500 XT's DisplayPort at this time.
>
>
> I'd like to get my graphics card working... :-/ Any ideas?

Please try a 5.5 kernel.  Some users are reporting problems on 5.4.

Alex