drm/i915/dg2: Add Wa_14010547955

This workaround is documented a bit strangely in the bspec; it's listed
as an A0 workaround, but the description clarifies that the workaround
is implicitly handled by the hardware and what the driver really needs
to do is program a chicken bit to reenable some internal behavior.

Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Clint Taylor <Clinton.A.Taylor@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211116174818.2128062-3-matthew.d.roper@intel.com

drivers/gpu/drm/i915/display/intel_display.c

@@ -991,6 +991,10 @@ static void icl_set_pipe_chicken(const struct intel_crtc_state *crtc_state)
 	else if (DISPLAY_VER(dev_priv) >= 13)
 		tmp |= UNDERRUN_RECOVERY_DISABLE_ADLP;
 
+	/* Wa_14010547955:dg2 */
+	if (IS_DG2_DISPLAY_STEP(dev_priv, STEP_B0, STEP_FOREVER))
+		tmp |= DG2_RENDER_CCSTAG_4_3_EN;
+
 	intel_de_write(dev_priv, PIPE_CHICKEN(pipe), tmp);
 }
 

drivers/gpu/drm/i915/i915_reg.h

@@ -8483,8 +8483,9 @@ enum {
 							   _PIPEB_CHICKEN)
 #define   UNDERRUN_RECOVERY_DISABLE_ADLP	REG_BIT(30)
 #define   UNDERRUN_RECOVERY_ENABLE_DG2		REG_BIT(30)
-#define   PIXEL_ROUNDING_TRUNC_FB_PASSTHRU 	(1 << 15)
-#define   PER_PIXEL_ALPHA_BYPASS_EN		(1 << 7)
+#define   PIXEL_ROUNDING_TRUNC_FB_PASSTHRU	REG_BIT(15)
+#define   DG2_RENDER_CCSTAG_4_3_EN		REG_BIT(12)
+#define   PER_PIXEL_ALPHA_BYPASS_EN		REG_BIT(7)
 
 #define FF_MODE2			_MMIO(0x6604)
 #define   FF_MODE2_GS_TIMER_MASK	REG_GENMASK(31, 24)