[Intel-gfx] [PATCH] drm: avoid spurious EBUSY due to nonblocking atomic modesets

[Daniel Vetter]

On Thu, May 14, 2020 at 8:42 AM Daniel Stone <daniel at fooishbar.org> wrote:
>
> On Wed, 8 Apr 2020 at 17:24, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> > Resending because last attempt failed CI and meanwhile the results are
> > lost :-/
>
> Did anything happen with this?

Nope. There's an igt now that fails with this, and I'm not sure
whether changing the igt is the right idea or not.

I'm kinda now thinking about changing this to instead document under
which exact situations you can get a spurious EBUSY, and enforcing
that in the code with some checks. Essentially only possible if you do
a ALLOW_MODESET | NONBLOCKING on the other crtc. And then tell
userspace you get to eat that. We've been shipping with this for so
long by now that's defacto the uapi anyway :-/

Thoughts? Too horrible?
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch