1698366 - Random artefacts now appear on the screen with Ubuntu 18.04.5 LTS - they did not in the past

Status: RESOLVED DUPLICATE of bug 1679681

(Core :: Graphics, defect, P3)

Description

[Gareth Jenkins]

Attachment: Screen shot showing artefacts

User Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.182 Safari/537.36 OPR/74.0.3911.203

Steps to reproduce:

Problem occurs every time I start Firefox and occurs the whole time I use Firefox. I have used Firefox for many years and this did not happen in the past with Ubuntu 18.04 so I assume something has changed in Ubuntu or Firefox to cause the problem.

Actual results:

Small rectangles in different colours appear at random locations on the screen. Their position changes. Sometimes there are so many it is hard to read the screen, making Firefox unusable. This problem only happens with Firefox. I have switched to using Opera at the moment as this does not have the same issue.

Refreshing Firefox and clearing the startup cache did not solve the problem.

Expected results:

There should not have been any artefacts on the display.

Comment 1

[Jamie Nicol [:jnicol]]

Hi Gareth, thanks for the bug report. Could you please go to the page "about:support", click on "copy text to clipboard" and attach that information to this bug. This will tell us things like which version of firefox are you running, what GPU and mesa version you have.

I think this is likely a bug in Mesa, and the reason it has recently appeared for you is because Firefox has recently enabled webrender, our GPU-based rendering engine.

Comment 2

[Gareth Jenkins]

Attachment: Firefox aboutsupport clipboard info.odt

Dump of about:support info.

Comment 3

[Gareth Jenkins]

(In reply to Jamie Nicol [:jnicol] from comment #1)

Hi Gareth, thanks for the bug report. Could you please go to the page "about:support", click on "copy text to clipboard" and attach that information to this bug. This will tell us things like which version of firefox are you running, what GPU and mesa version you have.

I think this is likely a bug in Mesa, and the reason it has recently appeared for you is because Firefox has recently enabled webrender, our GPU-based rendering engine.

Hi Jamie

Thanks for the prompt response. I have uploaded the about:support info as requested.

Gareth

Comment 4

[Andrew Osmond [:aosmond] (he/him)]

This is likely a dupe of the other mesa/r600 bugs fixed in 88 by bug 1694909.

Comment 5

[Robert Mader [:rmader]]

Gareth: you can likely work around the issue (driver bug) by setting gfx.webrender.force-disabled to true in about:config for the time being.

Comment 6

[Jamie Nicol [:jnicol]]

Or alternatively you could try downloading Firefox nightly and see if the issue is fixed there: https://www.mozilla.org/en-GB/firefox/channel/desktop/

Comment 7

[Gareth Jenkins]

(In reply to Robert Mader [:rmader] from comment #5)

Gareth: you can likely work around the issue (driver bug) by setting gfx.webrender.force-disabled to true in about:config for the time being.

Robert
Many thanks - I have made that change and as you forecast it has been a successful workaround for now.
Gareth

Comment 8

[Robert Mader [:rmader]]

Marking as dup of bug 1679681 then (which links to the fix in bug 1694909).