drm/i915: Fix LVDS stability issue on Ironlake

In disable sequence, all output ports on PCH have to be disabled
before PCH transcoder, but LVDS port was left always enabled. This
one fixes that by disable LVDS port properly during pipe disable
process, and resolved stability issue seen on Ironlake. Also move
panel fitting disable time just after pipe disable to align with
the spec.
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: NEric Anholt <eric@anholt.net>

drivers/gpu/drm/i915/intel_display.c

@@ -1488,6 +1488,15 @@ static void igdng_crtc_dpms(struct drm_crtc *crtc, int mode)
 	case DRM_MODE_DPMS_STANDBY:
 	case DRM_MODE_DPMS_SUSPEND:
 		DRM_DEBUG_KMS("crtc %d dpms on\n", pipe);
+
+		if (intel_pipe_has_type(crtc, INTEL_OUTPUT_LVDS)) {
+			temp = I915_READ(PCH_LVDS);
+			if ((temp & LVDS_PORT_EN) == 0) {
+				I915_WRITE(PCH_LVDS, temp | LVDS_PORT_EN);
+				POSTING_READ(PCH_LVDS);
+			}
+		}
+
 		if (HAS_eDP) {
 			/* enable eDP PLL */
 			igdng_enable_pll_edp(crtc);
@@ -1674,8 +1683,6 @@ static void igdng_crtc_dpms(struct drm_crtc *crtc, int mode)
 	case DRM_MODE_DPMS_OFF:
 		DRM_DEBUG_KMS("crtc %d dpms off\n", pipe);
 
-		i915_disable_vga(dev);
-
 		/* Disable display plane */
 		temp = I915_READ(dspcntr_reg);
 		if ((temp & DISPLAY_PLANE_ENABLE) != 0) {
@@ -1685,6 +1692,8 @@ static void igdng_crtc_dpms(struct drm_crtc *crtc, int mode)
 			I915_READ(dspbase_reg);
 		}
 
+		i915_disable_vga(dev);
+
 		/* disable cpu pipe, disable after all planes disabled */
 		temp = I915_READ(pipeconf_reg);
 		if ((temp & PIPEACONF_ENABLE) != 0) {
@@ -1706,9 +1715,15 @@ static void igdng_crtc_dpms(struct drm_crtc *crtc, int mode)
 		} else
 			DRM_DEBUG_KMS("crtc %d is disabled\n", pipe);
 
-		if (HAS_eDP) {
-			igdng_disable_pll_edp(crtc);
+		udelay(100);
+
+		/* Disable PF */
+		temp = I915_READ(pf_ctl_reg);
+		if ((temp & PF_ENABLE) != 0) {
+			I915_WRITE(pf_ctl_reg, temp & ~PF_ENABLE);
+			I915_READ(pf_ctl_reg);
 		}
+		I915_WRITE(pf_win_size, 0);
 
 		/* disable CPU FDI tx and PCH FDI rx */
 		temp = I915_READ(fdi_tx_reg);
@@ -1734,6 +1749,13 @@ static void igdng_crtc_dpms(struct drm_crtc *crtc, int mode)
 
 		udelay(100);
 
+		if (intel_pipe_has_type(crtc, INTEL_OUTPUT_LVDS)) {
+			temp = I915_READ(PCH_LVDS);
+			I915_WRITE(PCH_LVDS, temp & ~LVDS_PORT_EN);
+			I915_READ(PCH_LVDS);
+			udelay(100);
+		}
+
 		/* disable PCH transcoder */
 		temp = I915_READ(transconf_reg);
 		if ((temp & TRANS_ENABLE) != 0) {
@@ -1754,6 +1776,8 @@ static void igdng_crtc_dpms(struct drm_crtc *crtc, int mode)
 			}
 		}
 
+		udelay(100);
+
 		/* disable PCH DPLL */
 		temp = I915_READ(pch_dpll_reg);
 		if ((temp & DPLL_VCO_ENABLE) != 0) {
@@ -1761,14 +1785,20 @@ static void igdng_crtc_dpms(struct drm_crtc *crtc, int mode)
 			I915_READ(pch_dpll_reg);
 		}
 
-		temp = I915_READ(fdi_rx_reg);
-		if ((temp & FDI_RX_PLL_ENABLE) != 0) {
-			temp &= ~FDI_SEL_PCDCLK;
-			temp &= ~FDI_RX_PLL_ENABLE;
-			I915_WRITE(fdi_rx_reg, temp);
-			I915_READ(fdi_rx_reg);
+		if (HAS_eDP) {
+			igdng_disable_pll_edp(crtc);
 		}
 
+		temp = I915_READ(fdi_rx_reg);
+		temp &= ~FDI_SEL_PCDCLK;
+		I915_WRITE(fdi_rx_reg, temp);
+		I915_READ(fdi_rx_reg);
+
+		temp = I915_READ(fdi_rx_reg);
+		temp &= ~FDI_RX_PLL_ENABLE;
+		I915_WRITE(fdi_rx_reg, temp);
+		I915_READ(fdi_rx_reg);
+
 		/* Disable CPU FDI TX PLL */
 		temp = I915_READ(fdi_tx_reg);
 		if ((temp & FDI_TX_PLL_ENABLE) != 0) {
@@ -1777,16 +1807,8 @@ static void igdng_crtc_dpms(struct drm_crtc *crtc, int mode)
 			udelay(100);
 		}
 
-		/* Disable PF */
-		temp = I915_READ(pf_ctl_reg);
-		if ((temp & PF_ENABLE) != 0) {
-			I915_WRITE(pf_ctl_reg, temp & ~PF_ENABLE);
-			I915_READ(pf_ctl_reg);
-		}
-		I915_WRITE(pf_win_size, 0);
-
 		/* Wait for the clocks to turn off. */
-		udelay(150);
+		udelay(100);
 		break;
 	}
 }