hwacc branch builds that use minigbm will switch to software compositor on amd.

[Bram Stolk]

This pertains to the hwacc branches of snap_from_source chromium builds.

Following the guide-0.9.1, we switched from system gbm to minigbm.
(These switches are in args.gn)

use_system_minigbm = false
use_intel_minigbm = true
use_amdgpu_minigbm = true

This enables us to better support intel hardware.

However, there seems to be a regression on other gpus.

Chromium will switch to software compositing on amd.
When I revert back to system gbm, I get hardware compositing again.

See attached screenshot.

To reproduce: build chromium in two different ways, and compare the output from the chrome://gpu url.

tested on: Radeon RX580 GPU.

[Bram Stolk (b-stolk)]

The previous test was on a chromium 107 build.
I re-tested it on a chromium 110 build with minigbm, and it shows the same result on rx580 gpu:
software compositing.

[Bram Stolk (b-stolk)]

NOTE: The non-expansion of DRI_DRIVER_DIR can muddle things, so that needs to be worked around before drawing conclusions from the logs.

[Bram Stolk (b-stolk)]

With the DRI_DRIVER_DIR issue out of the way, I see:

WARNING:ozone_platform_wayland.cc(273)] Failed to find drm render node path.
WARNING:wayland_buffer_manager_gpu.cc(437)] Failed to initialize drm render node handle.

render node is present:
$ ls -al /dev/dri/
total 0
drwxr-xr-x 3 root root 100 Feb 16 18:32 .
drwxr-xr-x 22 root root 5800 Feb 17 08:00 ..
drwxr-xr-x 2 root root 80 Feb 17 08:00 by-path
crw-rw----+ 1 root video 226, 0 Feb 17 08:00 card0
crw-rw----+ 1 root render 226, 128 Feb 16 18:32 renderD128

[Bram Stolk (b-stolk)]

I've added logging to
third_party/minigbm/src/amdgpu.c
third_party/minigbm/src/drv.c

This yielded:

drm_version->name: amdgpu
backend_list[0] = amdgpu
drv_get_backend(13) returned 0x55bf084e4338
dri_init() failed for path /usr/lib/x86_64-linux-gnu/dri/radeonsi_dri.so driver radeonsi: No such file or directory
backend init() failed: -19
[27925:27925:0221/111810.067118:WARNING:ozone_platform_wayland.cc(273)] Failed to find drm render node path.
[27925:27925:0221/111810.068456:WARNING:wayland_buffer_manager_gpu.cc(437)] Failed to initialize drm render node handle.

Checking with:

sudo snap run --shell chromium

...it turns out that there is no /usr/lib/x86_64-linux-gnu/dri/ directory in the snap.

NOTE: There is a /snap/gnome-3-38-2004/current/usr/lib/x86_64-linux-gnu/dri directory, but that only contains video drivers, like radeonsi_drv_video.so

[Bram Stolk (b-stolk)]

Hard-coding the dri directory to point to the snap's dri dir at:
/snap/gnome-3-38-2004/current/usr/lib/x86_64-linux-gnu/dri
fixes this, as I now see:

Graphics Feature Status
Canvas: Hardware accelerated
Canvas out-of-process rasterization: Disabled
Direct Rendering Display Compositor: Disabled
Compositing: Hardware accelerated
Multiple Raster Threads: Enabled
OpenGL: Enabled
Rasterization: Hardware accelerated
Raw Draw: Disabled
Video Decode: Hardware accelerated
Video Encode: Software only. Hardware acceleration disabled
Vulkan: Disabled
WebGL: Hardware accelerated
WebGL2: Hardware accelerated
WebGPU: Disabled