drm/i915/psr: Make MASK_DISP_REG_WRITE reserved in PSR_MASK for ICL

ICL spec states that this bit is now reserved.

Bspec: 7722

v2(Dhinakaran and Jani):
- instead of remove bit in gen11 now only setting if if gen < 11
- changed commit title

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181003205031.32474-2-jose.souza@intel.com

drivers/gpu/drm/i915/i915_reg.h

@@ -4195,7 +4195,7 @@ enum {
 #define   EDP_PSR_DEBUG_MASK_LPSP              (1 << 27)
 #define   EDP_PSR_DEBUG_MASK_MEMUP             (1 << 26)
 #define   EDP_PSR_DEBUG_MASK_HPD               (1 << 25)
-#define   EDP_PSR_DEBUG_MASK_DISP_REG_WRITE    (1 << 16)
+#define   EDP_PSR_DEBUG_MASK_DISP_REG_WRITE    (1 << 16) /* Reserved in ICL+ */
 #define   EDP_PSR_DEBUG_EXIT_ON_PIXEL_UNDERRUN (1 << 15) /* SKL+ */
 
 #define EDP_PSR2_CTL			_MMIO(0x6f900)
@@ -4232,7 +4232,7 @@ enum {
 #define  PSR_EVENT_FRONT_BUFFER_MODIFY		(1 << 9)
 #define  PSR_EVENT_WD_TIMER_EXPIRE		(1 << 8)
 #define  PSR_EVENT_PIPE_REGISTERS_UPDATE	(1 << 6)
-#define  PSR_EVENT_REGISTER_UPDATE		(1 << 5)
+#define  PSR_EVENT_REGISTER_UPDATE		(1 << 5) /* Reserved in ICL+ */
 #define  PSR_EVENT_HDCP_ENABLE			(1 << 4)
 #define  PSR_EVENT_KVMR_SESSION_ENABLE		(1 << 3)
 #define  PSR_EVENT_VBI_ENABLE			(1 << 2)

drivers/gpu/drm/i915/intel_psr.c

@@ -563,6 +563,7 @@ static void intel_psr_enable_source(struct intel_dp *intel_dp,
 {
 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
 	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
+	u32 mask;
 
 	/* Only HSW and BDW have PSR AUX registers that need to be setup. SKL+
 	 * use hardcoded values PSR AUX transactions
@@ -588,12 +589,15 @@ static void intel_psr_enable_source(struct intel_dp *intel_dp,
 	 * runtime_pm besides preventing  other hw tracking issues now we
 	 * can rely on frontbuffer tracking.
 	 */
-	I915_WRITE(EDP_PSR_DEBUG,
-		   EDP_PSR_DEBUG_MASK_MEMUP |
-		   EDP_PSR_DEBUG_MASK_HPD |
-		   EDP_PSR_DEBUG_MASK_LPSP |
-		   EDP_PSR_DEBUG_MASK_DISP_REG_WRITE |
-		   EDP_PSR_DEBUG_MASK_MAX_SLEEP);
+	mask = EDP_PSR_DEBUG_MASK_MEMUP |
+	       EDP_PSR_DEBUG_MASK_HPD |
+	       EDP_PSR_DEBUG_MASK_LPSP |
+	       EDP_PSR_DEBUG_MASK_MAX_SLEEP;
+
+	if (INTEL_GEN(dev_priv) < 11)
+		mask |= EDP_PSR_DEBUG_MASK_DISP_REG_WRITE;
+
+	I915_WRITE(EDP_PSR_DEBUG, mask);
 }
 
 static void intel_psr_enable_locked(struct drm_i915_private *dev_priv,