944915 - flickering on Linux with OMTC

Status: RESOLVED WONTFIX

(Core :: Graphics: Layers, defect)

Description

[Tasos Sahanidis]

Attachment: Hardware acceleration issue on Nightly

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:28.0) Gecko/20100101 Firefox/28.0 (Beta/Release)
Build ID: 20131127104324

Steps to reproduce:

Ran latest Firefox Nightly with layers.acceleration.force-enabled set to true on about:config.


Actual results:

Flickering on both the UI and the rendered page.
It is more noticeable when a video is playing (for example from Youtube) whether it is html5 or flash player, as the whole page flickers along with the UI scrollbar.
Additionally there is some typing delay on certain pages (Mozilla bugzilla included) and when right clicking, sometimes only the border of the context menu gets rendered until you hover over it.


Expected results:

No flickering and rendering issues, just like the previous versions of Nightly.
This seems to be the last version of nightly which is not affected by this issue: http://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/2013-11-27-10-43-24-oak/firefox-28.0a1.en-US.linux-x86_64.tar.bz2

Comment 1

[[:Aleksej]]

> http://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/2013-11-27-10-43-24-oak/firefox-28.0a1.en-US.linux-x86_64.tar.bz2

Not sure it's the branch you wanted to test: note the "oak".

Please post the exact regression range (last good, first bad, preferably with the SourceStamp= from application.ini, because it shows the check-in) and the Graphics section from about:support.

Thanks!

Comment 2

[Tasos Sahanidis]

Attachment: about:support output

Apologies, you are right, I meant the mozilla-central branch.
So the last good build's source stamp is 99479edbee2a (http://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/2013-11-26-05-20-50-mozilla-central/) and the first bad is 6ecf0c4dfcbe (http://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/2013-11-27-03-02-01-mozilla-central/)
I have attached the info requested from about:support.
I would also like to point out, that I made the same test with a fresh profile, but had the same results.

Comment 3

[[:Aleksej]]

https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=99479edbee2a&tochange=6ecf0c4dfcbe

Searching for "GL", there are patches for bug 924403.  CCing Nick Cameron.

Comment 4

[[:Aleksej]]

(and thanks for finding!)

Comment 5

[Nick Cameron [:nrc]]

We have changed from using main-thread to off-main-thread rendering on Linux when you force hardware acceleration. See http://featherweightmusings.blogspot.co.nz/2013/11/no-more-main-thread-opengl-in-firefox.html. So this is presumably a bug with OMTC on your system. The only short term solution is not to force HWA.

It would be most useful to find out why the reporter sees flickering but most users don't in order to fix this bug.

(Changing status to 'new' because I can really believe it happens, not because I have personally confirmed it).

Comment 6

[u279076]

Is this still reproducible?

Comment 7

[Tasos Sahanidis]

I have since changed my main computer to Nvidia graphics and since AMD stopped updating fglrx, that AMD card now runs on the open source Radeon driver with Mesa.

So unfortunately I can't tell if it is still reproducible, as I am no longer using the same hardware/software combination that caused the above issue.