From d2bdb604841a1bd8938439579db25b8e03fc4108 Mon Sep 17 00:00:00 2001
From: Matt Roper <matthew.d.roper@intel.com>
Date: Tue, 27 Jul 2021 07:50:56 -0700
Subject: drm/i915/adl_p: Allow underrun recovery when possible
Git-commit: ba3b049f477436b7e4bb19c293c78c9068582d54
Patch-mainline: v5.15-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

ADL_P requires that we disable underrun recovery when downscaling (or
using the scaler for YUV420 pipe output), using DSC, or using PSR2.
Otherwise we should be able to enable the underrun recovery.

On DG2 we need to keep underrun recovery disabled at all times, but the
chicken bit in PIPE_CHICKEN has an inverted meaning (it's an enable bit
instead of disable).

v2:
 - Reverse the condition (clear the disable bit when supported, set
   disable bit when not supported).

Bspec: 50351
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210727145056.2049720-1-matthew.d.roper@intel.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/i915/display/intel_display.c | 50 +++++++++++++-------
 drivers/gpu/drm/i915/i915_reg.h              |  3 +-
 2 files changed, 36 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 4c775a3ed1d0..8614f991b6e8 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -2211,8 +2211,26 @@ void intel_display_finish_reset(struct drm_i915_private *dev_priv)
 	clear_bit_unlock(I915_RESET_MODESET, &dev_priv->gt.reset.flags);
 }
 
-static void icl_set_pipe_chicken(struct intel_crtc *crtc)
+static bool underrun_recovery_supported(const struct intel_crtc_state *crtc_state)
 {
+	if (crtc_state->pch_pfit.enabled &&
+	    (crtc_state->pipe_src_w > drm_rect_width(&crtc_state->pch_pfit.dst) ||
+	     crtc_state->pipe_src_h > drm_rect_height(&crtc_state->pch_pfit.dst) ||
+	     crtc_state->output_format == INTEL_OUTPUT_FORMAT_YCBCR420))
+		return false;
+
+	if (crtc_state->dsc.compression_enable)
+		return false;
+
+	if (crtc_state->has_psr2)
+		return false;
+
+	return true;
+}
+
+static void icl_set_pipe_chicken(const struct intel_crtc_state *crtc_state)
+{
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
 	enum pipe pipe = crtc->pipe;
 	u32 tmp;
@@ -2233,19 +2251,19 @@ static void icl_set_pipe_chicken(struct intel_crtc *crtc)
 	 */
 	tmp |= PIXEL_ROUNDING_TRUNC_FB_PASSTHRU;
 
-	/*
-	 * "The underrun recovery mechanism should be disabled
-	 *  when the following is enabled for this pipe:
-	 *  WiDi
-	 *  Downscaling (this includes YUV420 fullblend)
-	 *  COG
-	 *  DSC
-	 *  PSR2"
-	 *
-	 * FIXME: enable whenever possible...
-	 */
-	if (IS_ALDERLAKE_P(dev_priv))
-		tmp |= UNDERRUN_RECOVERY_DISABLE;
+	if (IS_DG2(dev_priv)) {
+		/*
+		 * Underrun recovery must always be disabled on DG2.  However
+		 * the chicken bit meaning is inverted compared to other
+		 * platforms.
+		 */
+		tmp &= ~UNDERRUN_RECOVERY_ENABLE_DG2;
+	} else if (DISPLAY_VER(dev_priv) >= 13) {
+		if (underrun_recovery_supported(crtc_state))
+			tmp &= ~UNDERRUN_RECOVERY_DISABLE_ADLP;
+		else
+			tmp |= UNDERRUN_RECOVERY_DISABLE_ADLP;
+	}
 
 	intel_de_write(dev_priv, PIPE_CHICKEN(pipe), tmp);
 }
@@ -3583,7 +3601,7 @@ static void hsw_crtc_enable(struct intel_atomic_state *state,
 	hsw_set_linetime_wm(new_crtc_state);
 
 	if (DISPLAY_VER(dev_priv) >= 11)
-		icl_set_pipe_chicken(crtc);
+		icl_set_pipe_chicken(new_crtc_state);
 
 	if (dev_priv->display.initial_watermarks)
 		dev_priv->display.initial_watermarks(state, crtc);
@@ -10229,7 +10247,7 @@ static void intel_pipe_fastset(const struct intel_crtc_state *old_crtc_state,
 		hsw_set_linetime_wm(new_crtc_state);
 
 	if (DISPLAY_VER(dev_priv) >= 11)
-		icl_set_pipe_chicken(crtc);
+		icl_set_pipe_chicken(new_crtc_state);
 }
 
 static void commit_pipe_pre_planes(struct intel_atomic_state *state,
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index f26e73606238..3710b45a4bc2 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -8442,7 +8442,8 @@ enum {
 #define _PIPEC_CHICKEN				0x72038
 #define PIPE_CHICKEN(pipe)			_MMIO_PIPE(pipe, _PIPEA_CHICKEN,\
 							   _PIPEB_CHICKEN)
-#define   UNDERRUN_RECOVERY_DISABLE		REG_BIT(30)
+#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)
 
-- 
2.38.1