[Intel-gfx] [PATCH 2/2] drm/i915/guc: default to using GuC submission where possible

[Chris Wilson]

On Fri, Apr 22, 2016 at 07:45:15PM +0100, Chris Wilson wrote:
> On Fri, Apr 22, 2016 at 07:22:55PM +0100, Dave Gordon wrote:
> > This patch simply changes the default value of "enable_guc_submission"
> > from 0 (never) to -1 (auto). This means that GuC submission will be
> > used if the platform has a GuC, the GuC supports the request submission
> > protocol, and any required GuC firmwware was successfully loaded. If any
> > of these conditions are not met, the driver will fall back to using
> > execlist mode.

I just remembered something else.

 * Work Items:
 * There are several types of work items that the host may place into a
 * workqueue, each with its own requirements and limitations. Currently only
 * WQ_TYPE_INORDER is needed to support legacy submission via GuC, which
 * represents in-order queue. The kernel driver packs ring tail pointer and an
 * ELSP context descriptor dword into Work Item.

Is this right? You only allocate a single client covering all engines and
specify INORDER. We expect parallel execution between engines, is this
supported? Empirically it seems like guc is only executing commands in
series across engines and not in parallel.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre