drm/i915/bdw: Use timeout mode for RC6 on bdw

Higher RC6 residency is observed using timeout mode
instead of EI mode.  This applies to Broadwell only.
The difference is particularly noticeable with video
playback.

Signed-off-by: Tom O'Rourke <Tom.O'Rourke@intel.com>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 1cce0a59097967563934a28d8a9f72da1d8174c6..cb261457bfd10917851323ee20c3850fc9be2ba9 100644 (file)
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3486,15 +3486,23 @@ static void gen8_enable_rps(struct drm_device *dev)
        for_each_ring(ring, dev_priv, unused)
                I915_WRITE(RING_MAX_IDLE(ring->mmio_base), 10);
        I915_WRITE(GEN6_RC_SLEEP, 0);
-       I915_WRITE(GEN6_RC6_THRESHOLD, 50000); /* 50/125ms per EI */
+       if (IS_BROADWELL(dev))
+               I915_WRITE(GEN6_RC6_THRESHOLD, 625); /* 800us/1.28 for TO */
+       else
+               I915_WRITE(GEN6_RC6_THRESHOLD, 50000); /* 50/125ms per EI */
 
        /* 3: Enable RC6 */
        if (intel_enable_rc6(dev) & INTEL_RC6_ENABLE)
                rc6_mask = GEN6_RC_CTL_RC6_ENABLE;
        intel_print_rc6_info(dev, rc6_mask);
-       I915_WRITE(GEN6_RC_CONTROL, GEN6_RC_CTL_HW_ENABLE |
-                                   GEN6_RC_CTL_EI_MODE(1) |
-                                   rc6_mask);
+       if (IS_BROADWELL(dev))
+               I915_WRITE(GEN6_RC_CONTROL, GEN6_RC_CTL_HW_ENABLE |
+                               GEN7_RC_CTL_TO_MODE |
+                               rc6_mask);
+       else
+               I915_WRITE(GEN6_RC_CONTROL, GEN6_RC_CTL_HW_ENABLE |
+                               GEN6_RC_CTL_EI_MODE(1) |
+                               rc6_mask);
 
        /* 4 Program defaults and thresholds for RPS*/
        I915_WRITE(GEN6_RPNSWREQ,