- Fix PCH reference clock for FDI on HSW/BDW which was causing users blank screen

- Small documentation fix for TGL display PLLs
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Merge tag 'drm-intel-fixes-2019-10-31' of git://anongit.freedesktop.org/drm/drm-intel into drm-fixes

- Fix PCH reference clock for FDI on HSW/BDW which was causing users blank screen
- Small documentation fix for TGL display PLLs

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191031171209.GA6586@intel.com

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

@@ -9315,7 +9315,6 @@ static bool wrpll_uses_pch_ssc(struct drm_i915_private *dev_priv,
 static void lpt_init_pch_refclk(struct drm_i915_private *dev_priv)
 {
 	struct intel_encoder *encoder;
-	bool pch_ssc_in_use = false;
 	bool has_fdi = false;
 
 	for_each_intel_encoder(&dev_priv->drm, encoder) {
@@ -9343,22 +9342,24 @@ static void lpt_init_pch_refclk(struct drm_i915_private *dev_priv)
 	 * clock hierarchy. That would also allow us to do
 	 * clock bending finally.
 	 */
+	dev_priv->pch_ssc_use = 0;
+
 	if (spll_uses_pch_ssc(dev_priv)) {
 		DRM_DEBUG_KMS("SPLL using PCH SSC\n");
-		pch_ssc_in_use = true;
+		dev_priv->pch_ssc_use |= BIT(DPLL_ID_SPLL);
 	}
 
 	if (wrpll_uses_pch_ssc(dev_priv, DPLL_ID_WRPLL1)) {
 		DRM_DEBUG_KMS("WRPLL1 using PCH SSC\n");
-		pch_ssc_in_use = true;
+		dev_priv->pch_ssc_use |= BIT(DPLL_ID_WRPLL1);
 	}
 
 	if (wrpll_uses_pch_ssc(dev_priv, DPLL_ID_WRPLL2)) {
 		DRM_DEBUG_KMS("WRPLL2 using PCH SSC\n");
-		pch_ssc_in_use = true;
+		dev_priv->pch_ssc_use |= BIT(DPLL_ID_WRPLL2);
 	}
 
-	if (pch_ssc_in_use)
+	if (dev_priv->pch_ssc_use)
 		return;
 
 	if (has_fdi) {

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

@@ -525,16 +525,31 @@ static void hsw_ddi_wrpll_disable(struct drm_i915_private *dev_priv,
 	val = I915_READ(WRPLL_CTL(id));
 	I915_WRITE(WRPLL_CTL(id), val & ~WRPLL_PLL_ENABLE);
 	POSTING_READ(WRPLL_CTL(id));
+
+	/*
+	 * Try to set up the PCH reference clock once all DPLLs
+	 * that depend on it have been shut down.
+	 */
+	if (dev_priv->pch_ssc_use & BIT(id))
+		intel_init_pch_refclk(dev_priv);
 }
 
 static void hsw_ddi_spll_disable(struct drm_i915_private *dev_priv,
 				 struct intel_shared_dpll *pll)
 {
+	enum intel_dpll_id id = pll->info->id;
 	u32 val;
 
 	val = I915_READ(SPLL_CTL);
 	I915_WRITE(SPLL_CTL, val & ~SPLL_PLL_ENABLE);
 	POSTING_READ(SPLL_CTL);
+
+	/*
+	 * Try to set up the PCH reference clock once all DPLLs
+	 * that depend on it have been shut down.
+	 */
+	if (dev_priv->pch_ssc_use & BIT(id))
+		intel_init_pch_refclk(dev_priv);
 }
 
 static bool hsw_ddi_wrpll_get_hw_state(struct drm_i915_private *dev_priv,

drivers/gpu/drm/i915/display/intel_dpll_mgr.h

@@ -147,11 +147,11 @@ enum intel_dpll_id {
 	 */
 	DPLL_ID_ICL_MGPLL4 = 6,
 	/**
-	 * @DPLL_ID_TGL_TCPLL5: TGL TC PLL port 5 (TC5)
+	 * @DPLL_ID_TGL_MGPLL5: TGL TC PLL port 5 (TC5)
 	 */
 	DPLL_ID_TGL_MGPLL5 = 7,
 	/**
-	 * @DPLL_ID_TGL_TCPLL6: TGL TC PLL port 6 (TC6)
+	 * @DPLL_ID_TGL_MGPLL6: TGL TC PLL port 6 (TC6)
 	 */
 	DPLL_ID_TGL_MGPLL6 = 8,
 };

drivers/gpu/drm/i915/i915_drv.h

@@ -1723,6 +1723,8 @@ struct drm_i915_private {
 		struct work_struct idle_work;
 	} gem;
 
+	u8 pch_ssc_use;
+
 	/* For i945gm vblank irq vs. C3 workaround */
 	struct {
 		struct work_struct work;