amdgpu raven2 hang on gst-plugins-base testsuite

[Haelwenn Monnier (lanodan)]

Hello,

 Running the gst-plugins-base testsuite makes my Lenovo T459 entirely hang, to
the point where even SSH doesn't works.
 I also get quite random glitches while using mpv, specially HTTP streams (NFS is fine)
and browsing the web (webkit-gtk, firefox, chromium, …) but in this case
the driver manages to reset after a bit.

APU: AMD Ryzen 5 3500U Pro w/ Radeon Vega Mobile Gfx
Systems:
- Gentoo Linux (linux 5.10.41 + mesa 21.1.3)
- Alpine Linux edge (linux-lts 5.10.46)
Relevant lspci output:
06:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Picasso (rev d2)
06:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Raven/Raven2/Fenghuang HDMI/DP Audio Controller
06:00.2 Encryption controller: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 10h-1fh) Platform Security Processor
06:00.3 USB controller: Advanced Micro Devices, Inc. [AMD] Raven USB 3.1
06:00.4 USB controller: Advanced Micro Devices, Inc. [AMD] Raven USB 3.1
06:00.5 Multimedia controller: Advanced Micro Devices, Inc. [AMD] Raven/Raven2/FireFlight/Renoir Audio Processor
06:00.6 Audio device: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 10h-1fh) HD Audio Controller


 I had issues with mesa starting on 20.1.10, as seen in 
https://gitlab.freedesktop.org/mesa/mesa/-/issues/4100
but even on that version the gstreamer testsuite makes the display crash, 
the whole system doesn't hangs anymore though but I couldn't recover it,
I can send dmesg and other system logs to developers on request.

btw my desktop (AMD Ryzen 7 3700X + AMD Radeon RX5600XT) has a similar setup
and the gst-plugins-base testsuite just works fine.

Best regards,
Haelwenn (lanodan) Monnier