drm/i915: Skip force-wake for uncached mmio flush of GGTT writes

The trick of using an uncached mmio read to ensure that the GGTT writes
are flushed does not require us to do the forcewake dance, so avoid it
in the hope of reducing the frequency that we do keep the device forced
awake.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170318104257.694-1-chris@chris-wilson.co.uk
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
This commit is contained in:
Chris Wilson 2017-03-18 10:42:57 +00:00
parent c9203e8277
commit 54ec12af2f

View file

@ -3307,8 +3307,11 @@ i915_gem_object_flush_gtt_write_domain(struct drm_i915_gem_object *obj)
* system agents we cannot reproduce this behaviour).
*/
wmb();
if (INTEL_GEN(dev_priv) >= 6 && !HAS_LLC(dev_priv))
POSTING_READ(RING_ACTHD(dev_priv->engine[RCS]->mmio_base));
if (INTEL_GEN(dev_priv) >= 6 && !HAS_LLC(dev_priv)) {
spin_lock_irq(&dev_priv->uncore.lock);
POSTING_READ_FW(RING_ACTHD(dev_priv->engine[RCS]->mmio_base));
spin_unlock_irq(&dev_priv->uncore.lock);
}
intel_fb_obj_flush(obj, write_origin(obj, I915_GEM_DOMAIN_GTT));