Re: [2.6.39] drm/i915: blank screen on Lenovo Ideapad U160

[Dirk Gouders <gouders@et.bocholt.fh-gelsenkirchen.de>]

Jesse Barnes <jbarnes@virtuousgeek.org> writes:

> Oh is this not an LVDS panel?  I'm curious which of the port disables
> is at fault in your config then.  If you have an eDP panel, it would
> likely be the PCH_DP_D write.  It could be a side effect of the
> PANEL_UNLOCK_REGS write as well though, can you try commenting each of
> those out?

Yes, you are right.  Commenting out a single line helps:

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 81a9059..ed95cbf 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1356,7 +1356,7 @@ static void intel_disable_pch_ports(struct drm_i915_private *dev_priv,
        u32 reg, val;
 
        val = I915_READ(PCH_PP_CONTROL);
-       I915_WRITE(PCH_PP_CONTROL, val | PANEL_UNLOCK_REGS);
+       //I915_WRITE(PCH_PP_CONTROL, val | PANEL_UNLOCK_REGS);
 
        disable_pch_dp(dev_priv, pipe, PCH_DP_B);
        disable_pch_dp(dev_priv, pipe, PCH_DP_C);

Dirk