GNOME Bugzilla – Bug 674208
[PATCH] disable sub-buffer copies on software Mesa
Last modified: 2014-03-11 17:15:45 UTC
The "drisw" binding in Mesa for loading sofware renderers is broken, and neither glBlitFramebuffer nor glXCopySubBuffer work correctly. Effectively they always upload the entire image rather than just the desired region. This might get fixed someday, but in the meantime we should pretend those extensions don't exist.
Created attachment 212153 [details] [review] Describe the attachment briefly.
just as a data point, this has been fixed with the following commit in master: http://git.gnome.org/browse/cogl/commit/?id=11f2f6ebb42398978ec8dd92b3c332ae8140a728 but not in the cogl-1.10 branch.
I've backported that commit that Emmanuele mentioned to the cogl-1.10 branch. The hope is that if we use the cogl-gpu-info system then eventually if it gets fixed in Mesa we'll be able to add a maximum version number to the workaround. We're also trying to start a process so that whenever we make a release we grep for 'ongoing workarounds' to remind us to recheck whether the situation has changed. Thanks for the patch.
This bug is upstream in Mesa now: https://bugs.freedesktop.org/show_bug.cgi?id=75545 For a piglit test that exposes the bug, see http://lists.freedesktop.org/archives/piglit/2014-February/009701.html
For reference, the workaround was changed to only happen for certain versions of Mesa in bug #721450.