drm/i915: Store framestart_delay in dev_priv

The vrr calculations will need to know the framestart delay value
we use. Currently we program it always to zero, but should that change
we probably want to stash it somewhere.

Could stick it into the crtc_state I suppose, but since we never
change it let's just stuff it into dev_priv for now.

v2:
* Rebase on drm-tip (Manasi)

v3:
* Framestart_delay as 1 - 4 to align with HW
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210122232647.22688-3-manasi.d.navare@intel.com

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

@@ -845,7 +845,7 @@ static void ilk_enable_pch_transcoder(const struct intel_crtc_state *crtc_state)
 		val |= TRANS_CHICKEN2_TIMING_OVERRIDE;
 		/* Configure frame start delay to match the CPU */
 		val &= ~TRANS_CHICKEN2_FRAME_START_DELAY_MASK;
-		val |= TRANS_CHICKEN2_FRAME_START_DELAY(0);
+		val |= TRANS_CHICKEN2_FRAME_START_DELAY(dev_priv->framestart_delay - 1);
 		intel_de_write(dev_priv, reg, val);
 	}
 
@@ -856,7 +856,7 @@ static void ilk_enable_pch_transcoder(const struct intel_crtc_state *crtc_state)
 	if (HAS_PCH_IBX(dev_priv)) {
 		/* Configure frame start delay to match the CPU */
 		val &= ~TRANS_FRAME_START_DELAY_MASK;
-		val |= TRANS_FRAME_START_DELAY(0);
+		val |= TRANS_FRAME_START_DELAY(dev_priv->framestart_delay - 1);
 
 		/*
 		 * Make the BPC in transcoder be consistent with
@@ -901,7 +901,7 @@ static void lpt_enable_pch_transcoder(struct drm_i915_private *dev_priv,
 	val |= TRANS_CHICKEN2_TIMING_OVERRIDE;
 	/* Configure frame start delay to match the CPU */
 	val &= ~TRANS_CHICKEN2_FRAME_START_DELAY_MASK;
-	val |= TRANS_CHICKEN2_FRAME_START_DELAY(0);
+	val |= TRANS_CHICKEN2_FRAME_START_DELAY(dev_priv->framestart_delay - 1);
 	intel_de_write(dev_priv, TRANS_CHICKEN2(PIPE_A), val);
 
 	val = TRANS_ENABLE;
@@ -5415,7 +5415,7 @@ static void hsw_set_frame_start_delay(const struct intel_crtc_state *crtc_state)
 
 	val = intel_de_read(dev_priv, reg);
 	val &= ~HSW_FRAME_START_DELAY_MASK;
-	val |= HSW_FRAME_START_DELAY(0);
+	val |= HSW_FRAME_START_DELAY(dev_priv->framestart_delay - 1);
 	intel_de_write(dev_priv, reg, val);
 }
 
@@ -7128,13 +7128,12 @@ static void i9xx_set_pipeconf(const struct intel_crtc_state *crtc_state)
 
 	pipeconf |= PIPECONF_GAMMA_MODE(crtc_state->gamma_mode);
 
-	pipeconf |= PIPECONF_FRAME_START_DELAY(0);
+	pipeconf |= PIPECONF_FRAME_START_DELAY(dev_priv->framestart_delay - 1);
 
 	intel_de_write(dev_priv, PIPECONF(crtc->pipe), pipeconf);
 	intel_de_posting_read(dev_priv, PIPECONF(crtc->pipe));
 }
 
-
 static bool i9xx_has_pfit(struct drm_i915_private *dev_priv)
 {
 	if (IS_I830(dev_priv))
@@ -8036,7 +8035,7 @@ static void ilk_set_pipeconf(const struct intel_crtc_state *crtc_state)
 
 	val |= PIPECONF_GAMMA_MODE(crtc_state->gamma_mode);
 
-	val |= PIPECONF_FRAME_START_DELAY(0);
+	val |= PIPECONF_FRAME_START_DELAY(dev_priv->framestart_delay - 1);
 
 	intel_de_write(dev_priv, PIPECONF(pipe), val);
 	intel_de_posting_read(dev_priv, PIPECONF(pipe));
@@ -14858,6 +14857,8 @@ int intel_modeset_init_noirq(struct drm_i915_private *i915)
 	i915->flip_wq = alloc_workqueue("i915_flip", WQ_HIGHPRI |
 					WQ_UNBOUND, WQ_UNBOUND_MAX_ACTIVE);
 
+	i915->framestart_delay = 1; /* 1-4 */
+
 	intel_mode_config_init(i915);
 
 	ret = intel_cdclk_init(i915);
@@ -15194,7 +15195,7 @@ static void intel_sanitize_frame_start_delay(const struct intel_crtc_state *crtc
 
 		val = intel_de_read(dev_priv, reg);
 		val &= ~HSW_FRAME_START_DELAY_MASK;
-		val |= HSW_FRAME_START_DELAY(0);
+		val |= HSW_FRAME_START_DELAY(dev_priv->framestart_delay - 1);
 		intel_de_write(dev_priv, reg, val);
 	} else {
 		i915_reg_t reg = PIPECONF(cpu_transcoder);
@@ -15202,7 +15203,7 @@ static void intel_sanitize_frame_start_delay(const struct intel_crtc_state *crtc
 
 		val = intel_de_read(dev_priv, reg);
 		val &= ~PIPECONF_FRAME_START_DELAY_MASK;
-		val |= PIPECONF_FRAME_START_DELAY(0);
+		val |= PIPECONF_FRAME_START_DELAY(dev_priv->framestart_delay - 1);
 		intel_de_write(dev_priv, reg, val);
 	}
 
@@ -15215,7 +15216,7 @@ static void intel_sanitize_frame_start_delay(const struct intel_crtc_state *crtc
 
 		val = intel_de_read(dev_priv, reg);
 		val &= ~TRANS_FRAME_START_DELAY_MASK;
-		val |= TRANS_FRAME_START_DELAY(0);
+		val |= TRANS_FRAME_START_DELAY(dev_priv->framestart_delay - 1);
 		intel_de_write(dev_priv, reg, val);
 	} else {
 		enum pipe pch_transcoder = intel_crtc_pch_transcoder(crtc);
@@ -15224,7 +15225,7 @@ static void intel_sanitize_frame_start_delay(const struct intel_crtc_state *crtc
 
 		val = intel_de_read(dev_priv, reg);
 		val &= ~TRANS_CHICKEN2_FRAME_START_DELAY_MASK;
-		val |= TRANS_CHICKEN2_FRAME_START_DELAY(0);
+		val |= TRANS_CHICKEN2_FRAME_START_DELAY(dev_priv->framestart_delay - 1);
 		intel_de_write(dev_priv, reg, val);
 	}
 }

drivers/gpu/drm/i915/i915_drv.h

@@ -1182,6 +1182,8 @@ struct drm_i915_private {
 		struct file *mmap_singleton;
 	} gem;
 
+	u8 framestart_delay;
+
 	u8 pch_ssc_use;
 
 	/* For i915gm/i945gm vblank irq workaround */