[Bug 51420] Running any program in Wine causes 100% cpu usage in Xorg

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=51420

--- Comment #37 from matt <gardotd426 at gmail.com> ---
(In reply to Kurt Kartaltepe from comment #36)
> I feel like this post is the blind leading the deaf, the author of the
> offending code has even responded on this thread, but not deigned to explain
> the issue.
> 
> When nvidia drivers are detected wine falls back to xrandr 1.0/1.1 for
> querying modes. As the author notes in their commit this is because they
> didn't like the modes reported by newer xrandr versions for DVI connections.
> 
> This is why d171d1116764260f4ae272c69b54e5dfd13c6835 which introduces many
> more queries to mode information to be a significant performance hit on
> nvidia with DVI connections. And why reverting the 1.0 fallback also fixes
> it (as we get the explicitly fast xrandr functions).
> 
> If you want to see if you are affected, well the first step is to see if you
> have a DVI device. The second step is you could run the same queries wine
> does and watch if your X11 session becomes unusable. For example `for x in
> $(seq 1 100); do xrandr --q1; done`, testing with a single DVI device shows
> the system crippled and testing with a single DP devices shows no
> significant impact.
> 
> Matt's rebase of the revert looks fine to me. When I tested the actual
> revert it also worked to avoid the excessive mode queries, as did removing
> the xrandr 1.0 fallback.

Yeah I don't know enough to dig through the code and find the original problem
or anything like that, but I did figure I could at least create a patch that
safely reverts the problematic code (since just reverting the original
offending commit isn't possible). Hopefully a better solution can be
constructed but until then yeah, my patch should work for anyone affected.

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