This is on Intel I guess? Your investigations into bug 1580792 does point out that the driver complains of a bad argument to glCopyTexSubImage - the only consumer of glCopyTexSubImage that I can find is in the Qt's font rendering system - so if it fails, it would cause font rendering issues. That's my best guess currently
This is on Intel I guess? Your investigations into bug 1580792 does point out that the driver complains of a bad argument to glCopyTexSubImage - the only consumer of glCopyTexSubImage that I can find is in the Qt's font rendering system - so if it fails, it would cause font rendering issues. That's my best guess currently