drm/i915: Remove unrequired POSTING_READ from gen6_set_rps()

The uncached mmio is sufficient to queue the mmio writes without raising
forcewake. The forced flush along with acquiring forcewake from the
posting read is not required for adjusting the RPS frequency.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170220094713.22874-3-chris@chris-wilson.co.uk
Reviewed-by: Radoslaw Szwichtenberg <radoslaw.szwichtenberg@intel.com>

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index af11c40..169c490 100644 (file)
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4939,8 +4939,6 @@ static int gen6_set_rps(struct drm_i915_private *dev_priv, u8 val)
        I915_WRITE(GEN6_RP_INTERRUPT_LIMITS, intel_rps_limits(dev_priv, val));
        I915_WRITE(GEN6_PMINTRMSK, gen6_rps_pm_mask(dev_priv, val));
 
-       POSTING_READ(GEN6_RPNSWREQ);
-
        dev_priv->rps.cur_freq = val;
        trace_intel_gpu_freq_change(intel_gpu_freq(dev_priv, val));