user32:clipboard CLIPBRDWNDCLASS interference (Radeon, others)

[Francois Gouget]

On Tue, 1 Jun 2021, Zebediah Figura wrote:
[...]
> > Furthermore, while it would likely greatly reduce the failure rate we'd
> > probably still get failures once in a while, likely at a rate so low it
> > would cause TestBot false positives. Just like on Nvidia actually (see
> > the cw-gtx560-1809-32 and cw-gtx560-1909-32 lines).
> 
> Or it's those "helpful" overlay/settings windows that always appear on
> startup. Maybe it's possible to just disable the service?

I tried that in the Radeon driver to no avail (I disabled In-Game 
Overlay, Advertisements, Toast Notifications, but also Upgrade Advisor,
Hotkeys (when possible), Check for Updates, System Tray Menu).

Another related bit is that user32:clipboard systematically succeeds 
right after boot. This is a pain when testing whether upgrading the 
driver helps: upgrade, reboot, all works, yay, problem solved! But then 
WineTest runs the tests in alphabetical order so by the time it gets to 
user32:* everything is broken again and confusion ensues :-(.

Now that I've identified the troublesome window as CLIPBRDWNDCLASS I see 
that it does not get created right away.

One thing that worked is killing the "Radeon Settings: Host Application" 
process.
* But that does not feel like a proper fix.
* I did not find a proper registry entry or service that I could disable 
  to prevent it from starting on boot.
* It does not work in newer Radeon driver versions, though maybe 
  disabling some service would work since CLIPBRDWNDCLASS is owned by 
  svchost.exe there.

I did not try tweaking the Nvidia driver settings.

-- 
Francois Gouget <fgouget at codeweavers.com>