drm/i915: update watermarks before enabling PLLs

When coming back from DPMS or turning on a display, make sure we have
the watermarks set up before turning on the display plane, otherwise we
may get underruns.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Tested-by: Dirk Hohndel <hohndel@infradead.org>
Signed-off-by: Eric Anholt <eric@anholt.net>

drivers/gpu/drm/i915/intel_display.c

@@ -1803,6 +1803,8 @@ static void i9xx_crtc_dpms(struct drm_crtc *crtc, int mode)
 	case DRM_MODE_DPMS_ON:
 	case DRM_MODE_DPMS_STANDBY:
 	case DRM_MODE_DPMS_SUSPEND:
+		intel_update_watermarks(dev);
+
 		/* Enable the DPLL */
 		temp = I915_READ(dpll_reg);
 		if ((temp & DPLL_VCO_ENABLE) == 0) {
@@ -1840,7 +1842,6 @@ static void i9xx_crtc_dpms(struct drm_crtc *crtc, int mode)
 
 		/* Give the overlay scaler a chance to enable if it's on this pipe */
 		//intel_crtc_dpms_video(crtc, true); TODO
-		intel_update_watermarks(dev);
 	break;
 	case DRM_MODE_DPMS_OFF:
 		intel_update_watermarks(dev);