Firefox testing - offscreen surfaces and OMTC

Martin Stransky stransky at redhat.com
Mon Aug 24 06:54:00 UTC 2015


On 08/21/2015 08:28 PM, Thomas Daede wrote:
> I've been running nightly with this enabled for quite a while on Intel
> and it's been fine.
>
> Note that OMTC is required for e10s.

If you mean OMTC by "this" then you're right - it works fine on nightly 
because nightly is built with in-tree cairo. Fedora it built with system 
cairo which causes crashes with OMTC enabled. First build which supports 
in-tree cairo & Gtk3 is FF41.

> The layer acceleration pref is a totally different thing and will stay
> off for the near future. It's affected by a bug in libxcb which has been
> patched but not made it to release yet:
> https://bugs.freedesktop.org/show_bug.cgi?id=84252

What do you mean here by "acceleration"? The offscreen surfaces 
referenced in this post are CPU rendering.

ma.

> On 08/21/2015 01:33 AM, Martin Stransky wrote:
>> Folks,
>>
>> I'd use some testing for new Firefox feature - offscreen surfaces [1].
>> It may also fix crashes when OMTC is enabled [2]. Browser should be a
>> bit faster with those features on.
>>
>> How to test?
>>
>> - Install Firefox 40 on Fedora 22,23,Rawhide (you'd need Gtk3 build)
>> - go to about:config, click to any key and add a new one, boolean type.
>> The new key name is "layers.use-image-offscreen-surfaces" and set it to
>> true.
>> - enable "layers.offmainthreadcomposition.enabled" which may be disabled
>> now.
>> - restart your browser.
>>
>> And you're set now. Please report any oddity (different than the usual
>> ones :)) at #BZ.
>>
>> Thanks!
>> ma.
>>
>> [1] https://bugzilla.mozilla.org/show_bug.cgi?id=1015218
>> [2] Off Main Thread Composition - layout rendering in separate thread.
>> New feature in Firefox 40.



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