Modesetting lock changes breaks vmwgfx since 3.18-rc1

[Daniel Vetter]

On Thu, Oct 30, 2014 at 03:41:31PM +0100, Thomas Hellstrom wrote:
> Hi!
> 
> Details in
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=1155825
> 
> Can whoever broke the driver please make an effort to fix it up?
> 
> Daniel, You've been named as a suspect. I'm not sure if that is true.

Yeah the recent locking frobbing didn't account for the FIXME comment in
vmwgfx. Might be good to address that long-term to get vmwgfx more in line
with everyone else again - I simply don't understand the interactions well
enough to make that call. There's two of those in total.

Can we just remove them perhaps? The question is whether you can do the
cursor operation just with the per-crtc lock as protection, or whether
there's any shared resources and you need the full exclusion provided by
modeset_lock_all. If the crtc locking is good enough then we could rip
this out in both function and be done.

Note that this FIXME has been in vmwgfx since almost two years now.

If that's not possible then I have a major kludge of a hack in my atomic
helpers branch which will keep this alive for a bit longer. It ain't
pretty though.

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