[Intel-gfx] [PATCH 09/50] drm/i915: Plumb the context everywhere in the execbuffer path

[Mateo Lozano, Oscar]

> -----Original Message-----
> From: Chris Wilson [mailto:chris at chris-wilson.co.uk]
> Sent: Friday, May 16, 2014 12:05 PM
> To: Mateo Lozano, Oscar
> Cc: intel-gfx at lists.freedesktop.org
> Subject: Re: [Intel-gfx] [PATCH 09/50] drm/i915: Plumb the context everywhere
> in the execbuffer path
> 
> On Fri, May 09, 2014 at 01:08:39PM +0100, oscar.mateo at intel.com wrote:
> > From: Oscar Mateo <oscar.mateo at intel.com>
> >
> > The context are going to become very important pretty soon, and we
> > need to be able to access them in a number of places inside the
> > command submission path. The idea is that, when we need to place
> > commands inside a ringbuffer or update the tail register, we know
> > which context we are working with.
> >
> > We left intel_ring_begin() as a function macro to quickly adapt legacy
> > code, an introduce intel_ringbuffer_begin() as the first of a set of
> > new functions for ringbuffer manipulation (the rest will come in
> > subsequent patches).
> >
> > No functional changes.
> >
> > v2: Do not set the context to NULL. In legacy code, set it to the
> > default ring context (even if it doesn't get used later on).
> 
> Won't rings be stored within the context? So the context should be derivable
> from which ring the operation is being issued on.
> -Chris

Rings (as in "engine command streamer") still remain in dev_priv and there are only four/five of them. What we store in the context is the new ringbuffer structure (which stores the head, tail, etc...) and the ringbuffer backing object. Knowing only the ring is not enough to derive the context.

- Oscar