[Intel-gfx] [RFC] async CRTC enable/disable hack

[Daniel Vetter]

On Fri, Dec 13, 2013 at 8:26 PM, Jesse Barnes <jbarnes at virtuousgeek.org> wrote:
> Obviously still need a lot of work (and I didn't quite get the patch
> split correctly, I meant commit the first bits earlier).
>
> I think the approach may be sound though, and is actually not too hard
> to get right with all the cross checking we have in place.  Things to
> fix:
>   - modeset cross check - we don't want to sync after a mode set just to
>     check, maybe we could put this off until the actual enable happens
>   - split flushing of disable and enable to actually make full mode sets
>     fast

When I've last pondered this async_domains looked like a suitable
thing. We can create as many of them as we want or reuse them, and
they have a nice primitive for syncing up with all previously launched
async work items. I haven't checked how well they take being called
from different processes (since we still want to do the very last sync
from a work item to fully asynchronously launch the the state
checker). But my impression was that they fit the bill or are at least
fairly close.

We could also try to abuse them in the driver load/suspend/resume code
and e.g. run the gem restore in parallel with early modeset stuff. I'm
not sure whether the syncing would be flexible enough though. But
worth a shot imo.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch