drm/i915: add panel reset workaround
authorJesse Barnes <jbarnes@virtuousgeek.org>
Wed, 11 Aug 2010 17:04:43 +0000 (10:04 -0700)
committerJesse Barnes <jbarnes@virtuousgeek.org>
Wed, 18 Aug 2010 19:57:21 +0000 (12:57 -0700)
Ironlake requires that we clear the reset panel bit during power
sequences and restore it afterwards.  Uncondtionally add code to do that
since it should be harmless on SNB+.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
drivers/gpu/drm/i915/intel_dp.c

index c6629bd9430f03276b2566d3ba0a4cc5258f66f7..d1b4ece4df0075de1736e2076cde4f47a2b583fb 100644 (file)
@@ -765,6 +765,12 @@ static void ironlake_edp_panel_on (struct drm_device *dev)
                return;
 
        pp = I915_READ(PCH_PP_CONTROL);
+
+       /* ILK workaround: disable reset around power sequence */
+       pp &= ~PANEL_POWER_RESET;
+       I915_WRITE(PCH_PP_CONTROL, pp);
+       POSTING_READ(PCH_PP_CONTROL);
+
        pp |= PANEL_UNLOCK_REGS | POWER_TARGET_ON;
        I915_WRITE(PCH_PP_CONTROL, pp);
 
@@ -773,7 +779,9 @@ static void ironlake_edp_panel_on (struct drm_device *dev)
                          I915_READ(PCH_PP_STATUS));
 
        pp &= ~(PANEL_UNLOCK_REGS | EDP_FORCE_VDD);
+       pp |= PANEL_POWER_RESET; /* restore panel reset bit */
        I915_WRITE(PCH_PP_CONTROL, pp);
+       POSTING_READ(PCH_PP_CONTROL);
 }
 
 static void ironlake_edp_panel_off (struct drm_device *dev)
@@ -782,6 +790,12 @@ static void ironlake_edp_panel_off (struct drm_device *dev)
        u32 pp;
 
        pp = I915_READ(PCH_PP_CONTROL);
+
+       /* ILK workaround: disable reset around power sequence */
+       pp &= ~PANEL_POWER_RESET;
+       I915_WRITE(PCH_PP_CONTROL, pp);
+       POSTING_READ(PCH_PP_CONTROL);
+
        pp &= ~POWER_TARGET_ON;
        I915_WRITE(PCH_PP_CONTROL, pp);
 
@@ -790,8 +804,9 @@ static void ironlake_edp_panel_off (struct drm_device *dev)
                          I915_READ(PCH_PP_STATUS));
 
        /* Make sure VDD is enabled so DP AUX will work */
-       pp |= EDP_FORCE_VDD;
+       pp |= EDP_FORCE_VDD | PANEL_POWER_RESET; /* restore panel reset bit */
        I915_WRITE(PCH_PP_CONTROL, pp);
+       POSTING_READ(PCH_PP_CONTROL);
 }
 
 static void ironlake_edp_backlight_on (struct drm_device *dev)