drm/i915: Support for RR switching on VLV

Definition of VLV RR switch bit and corresponding toggling in
set_drrs function.

Signed-off-by: Vandana Kannan <vandana.kannan@intel.com>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index c837ded..4d6e68c 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4825,9 +4825,15 @@
 		val = I915_READ(reg);
 
 		if (index > DRRS_HIGH_RR) {
-			val |= PIPECONF_EDP_RR_MODE_SWITCH;
+			if (IS_VALLEYVIEW(dev))
+				val |= PIPECONF_EDP_RR_MODE_SWITCH_VLV;
+			else
+				val |= PIPECONF_EDP_RR_MODE_SWITCH;
 		} else {
-			val &= ~PIPECONF_EDP_RR_MODE_SWITCH;
+			if (IS_VALLEYVIEW(dev))
+				val &= ~PIPECONF_EDP_RR_MODE_SWITCH_VLV;
+			else
+				val &= ~PIPECONF_EDP_RR_MODE_SWITCH;
 		}
 		I915_WRITE(reg, val);
 	}