[Intel-gfx] [PATCH] drm/i915: New vfunc prepare_request

[Chris Wilson]

On Mon, May 01, 2017 at 07:28:12AM +0000, Oscar Mateo wrote:
> 
> 
> On 04/29/2017 08:31 AM, Chris Wilson wrote:
> >On Fri, Apr 28, 2017 at 05:26:09PM +0000, Oscar Mateo wrote:
> >>This will be more useful later to support platforms that need to emit
> >>HW commands at the beginning of every request (more general than emitting
> >>things at the beginning of every batchbuffer, which is already covered by
> >>emit_bb_start).
> >We already have one... You are presenting this without a good reason and
> >failing to transform similar code, which indicates to me that this vfunc
> >isn't that general.
> 
> It looks like I've missed that. What function are you talking about?

For example, you can argue that both legacy ring submission and
execlists share the same sequence of request_alloc:

	request->ring = ce->ring (this is now common so can be moved
	out, thanks to unifying context pin)

	[guc_wq_reserve we have ideas how to eliminate]

	some rudimentary reserving of ring space

	context initialisation <- time to unify the legacy code

The choice for adding a new callback here, is we either take more common
code out of the request_alloc callback such that we reduce it to you new
vfunc -- and so we may end up with 2 common vfuncs called by the core.
Or you refactor the current code so that you can specialise request
alloc and use some execlist helpers for the common portion.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre