Re: [PATCH 02/15] drm/i915: Embedded microcontroller (uC) firmware loading support

Daniel Vetter
2015-06-18T15:32:44Z

On Thu, Jun 18, 2015 at 04:27:52PM +0100, Chris Wilson wrote:
> On Thu, Jun 18, 2015 at 04:49:49PM +0200, Daniel Vetter wrote:
> > Guc is different since we really must have it ready for execbuf, and for
> > that usecase a completion at drm_open time sounds like the right thing.
>
> But do we? It would be nice if we had a definite answer that the hw was
> ready before we started using it in anger, but I don't see any reason
> why we would have to delay userspace for a slow microcode update...
>
> (This presupposes that userspace batches are unaffected by GuC/execlist
> setup, which for userspace sanity I hope they are - or at least using
> predicate registers and conditional execution.)

Well I figured a wait_completion or flush_work unconditionally in execbuf
is not to your liking, and it's better to keep that in open. But I think
we should be able to get away with this at execbuf time. Might even be
better since this wouldn't block sw-rendered boot-splashs.

But either way should be suitable I think.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation