https://bugs.winehq.org/show_bug.cgi?id=43057
--- Comment #10 from Józef Kucia joseph.kucia@gmail.com --- (In reply to Henri Verbeet from comment #9)
(In reply to Józef Kucia from comment #6)
It would be interesting to know if the attached patch fixes the issue. It's a possible workaround for the Mesa bug.
For what it's worth, we'll want to make sure the Mesa bug gets fixed of course, but the patch seems legitimate enough.
Sure, I've submitted a bug report and a piglit test for the problem. I don't plan to work on the fix myself though.