drm/i915: Rearrange switch_context to load the aliasing ppgtt on first use
authorChris Wilson <chris@chris-wilson.co.uk>
Thu, 28 Apr 2016 08:56:45 +0000 (09:56 +0100)
committerChris Wilson <chris@chris-wilson.co.uk>
Thu, 28 Apr 2016 11:17:32 +0000 (12:17 +0100)
commitf9326be5f1d3ff2c689de8a1754bdafd03879b58
tree5b5c1ff8d74981a1e84a09ee380c53dd88155ca9
parentd200cda6bd9f7553cd83dee261ff593d6386aa0a
drm/i915: Rearrange switch_context to load the aliasing ppgtt on first use

The code to switch_mm() is already handled by i915_switch_context(), the
only difference required to setup the aliasing ppgtt is that we need to
emit te switch_mm() on the first context, i.e. when transitioning from
engine->last_context == NULL. This allows us to defer the
initialisation of the GPU from early device initialisation to first use,
which should marginally speed up both. The caveat is that we then defer
the context initialisation until first use - i.e. we cannot assume that
the GPU engines are initialised. For example, this means that power
contexts for rc6 (Ironlake) need to explicitly loaded, as they are.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1461833819-3991-11-git-send-email-chris@chris-wilson.co.uk
drivers/gpu/drm/i915/i915_drv.h
drivers/gpu/drm/i915/i915_gem.c
drivers/gpu/drm/i915/i915_gem_context.c
drivers/gpu/drm/i915/i915_gem_gtt.c
drivers/gpu/drm/i915/i915_gem_gtt.h