[Intel-gfx] [PATCH 1/2] drm/i915/guc: Simplify code by keeping kmap of guc_client object

[Yu Dai]

On 02/15/2016 07:23 AM, Dave Gordon wrote:
> On 12/02/16 13:03, Tvrtko Ursulin wrote:
> >
> > On 11/02/16 23:09, yu.dai at intel.com wrote:
> >> From: Alex Dai <yu.dai at intel.com>
> >>
> >> GuC client object is always pinned during its life cycle. We cache
> >> the kmap of its first page, which includes guc_process_desc and
> >> doorbell. By doing so, we can simplify the code where we read from
> >> this page to get where GuC is progressing on work queue; and the
> >> code where driver program doorbell to send work queue item to GuC.
>
> There's still one k(un)map_atomic() pair, in guc_add_workqueue_item().
> Maybe we could get rid of that one too? So instead of kmapping only the
> first page of the client, we could vmap() all three pages and so not
> need to kmap_atomic() the WQ pages on the fly.
>
> There's a handy vmap_obj() function we might use, except it's currently
> static ...
>
>
Yes, there is a vmap_obj we can use but it is static. Actually two, 
vmap_batch() in i915_cmd_parser.c and vmap_obj() in intel_ringbuffer.c. 
Maybe it is a good idea to make it global, so GuC can use it too.

Thanks,
Alex