FS#66185 - [firefox] Hardware accelerated WebGL renderer not being used even though it is available

Attached to Project: Arch Linux
Opened by Mathias Havdal (matte3560) - Thursday, 09 April 2020, 09:54 GMT
Last edited by freswa (frederik) - Sunday, 13 September 2020, 19:24 GMT
Task Type Bug Report
Category Packages: Extra
Status Closed
Assigned To Jan de Groot (JGC)
Jan Alexander Steffens (heftig)
Architecture All
Severity Medium
Priority Normal
Reported Version
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Votes 6
Private No

Details

Description:
WebGL appears to be falling back to the mesa llvmpipe renderer, even though a hardware accelerated renderer (mesa radeonsi) is reported in about:support.

Additional info:
* Appears to be a new issue in Firefox 75.0-1
* Tested with Radeon RX Vega 64 GPU with mesa 20.0.4-1

Steps to reproduce:
1. Check if hardware accelerated renderer is available in about:support
2. Check if hardware accelerated renderer is actually being used (ex. https://webglreport.com/ or alternatively check CPU usage on https://www.shadertoy.com/ )
This task depends upon

Closed by  freswa (frederik)
Sunday, 13 September 2020, 19:24 GMT
Reason for closing:  Fixed
Additional comments about closing:  Working as of firefox 80.0.1-1 + mesa 20.1.7-1 with a RX Vega 56.
Comment by Mathias Havdal (matte3560) - Thursday, 09 April 2020, 10:08 GMT
Appears to be related to this upstream bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1455498
I don't have LD_LIBRARY_PATH set, but the workaround suggested in comment #11 ( https://bugzilla.mozilla.org/show_bug.cgi?id=1455498#c11 ) fixes the issue. Maybe the mesa radeonsi libs are missing from a whitelist of some kind?
Comment by J (Holzprozessor) - Thursday, 09 April 2020, 11:57 GMT
I have the same problem since today, but with Intel HD graphics. I don't think this is related to Firefox, but rather a general problem. It used to work fine with Firefox 75.0-1 yesterday, but is not working today. The suggested workaround fixes the issue for me as well.

I have upgraded intel-media-driver to 20.1.1-1 yesterday before powering down my machine and assume that the problem stems from this upgrade.
Comment by Mathias Havdal (matte3560) - Thursday, 09 April 2020, 12:18 GMT
I have done some more digging. I downgraded libdrm and lib32-libdrm to version 2.4.100-1 and that fixed the problem. Seems like the issue is caused by libdrm 2.4.101-1. I also tested previous firefox versions and that had no impact on this issue.
Comment by Jan Alexander Steffens (heftig) - Thursday, 09 April 2020, 18:18 GMT
It's a sandboxing issue; dropping the sandbox level to 2 solves it.

libdrm 101 must be using new calls that aren't whitelisted yet.
Comment by Jan Alexander Steffens (heftig) - Thursday, 09 April 2020, 18:34 GMT Comment by J (Holzprozessor) - Thursday, 09 April 2020, 18:34 GMT
Please delete my comment
Comment by Lone_Wolf (Lone_Wolf) - Wednesday, 22 April 2020, 21:11 GMT
Posted this link already in  FS#66351  but that was closed as a duplicate.

https://gitlab.freedesktop.org/mesa/drm/-/issues/39 looks like the bug report where the root cause of this is investigated.

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