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

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Date:	Wed, 15 Jun 2011 11:59:03 -0700
From:	Jesse Barnes <jbarnes@...tuousgeek.org>
To:	Dirk Gouders <gouders@...bocholt.fh-gelsenkirchen.de>
Cc:	linux-kernel@...r.kernel.org,
	Chris Wilson <chris@...is-wilson.co.uk>
Subject: Re: [2.6.39] drm/i915: blank screen on Lenovo Ideapad U160

On Mon, 13 Jun 2011 23:21:12 +0200
Dirk Gouders <gouders@...bocholt.fh-gelsenkirchen.de> wrote:

> Dirk Gouders <gouders@...bocholt.fh-gelsenkirchen.de> writes:
> 
> > Dirk Gouders <gouders@...bocholt.fh-gelsenkirchen.de> writes:
> >
> >> "Robert P. J. Day" <rpjday@...shcourse.ca> writes:
> >>
> >>> On Tue, 31 May 2011, Dirk Gouders wrote:
> >>>
> >>>> Hello,
> >>>>
> >>>> I tested 3.0.0-rc1 on my notebook which has never been the best friend
> >>>> of the i915 driver.  With linux-2.6.38-gentoo-r4 it has the problem
> >>>> that the screen remains blank after the lid is closed and reopened, but
> >>>> that problem I can live with.  With 3.0.0-r1 I am back to a former
> >>>> problem that the screen goes (and remains) blank while booting.
> >>>>
> >>>> The next step I will do is to test linux-2.6.39-gentoo, probably I
> >>>> did not notice information that I have to adjust boot parameters or the
> >>>> kernel config?
> >>>
> >>>   based on my having lived through the i915 "black screen of death",
> >>> pulling out my handy "git bisect" and with advice from chris wilson,
> >>> these days, i simply apply this patch to the source:
> >>>
> >>> diff --git a/drivers/gpu/drm/i915/intel_opregion.c b/drivers/gpu/drm/i915/intel_opregion.c
> >>> index d2c7104..a1a5d03 100644
> >>> --- a/drivers/gpu/drm/i915/intel_opregion.c
> >>> +++ b/drivers/gpu/drm/i915/intel_opregion.c
> >>> @@ -152,6 +152,8 @@ static u32 asle_set_backlight(struct drm_device *dev, u32 bclp)
> >>>  	struct opregion_asle *asle = dev_priv->opregion.asle;
> >>>  	u32 max;
> >>>
> >>> +return ASLE_BACKLIGHT_FAILED; // rday
> >>> +
> >>>  	if (!(bclp & ASLE_BCLP_VALID))
> >>>  		return ASLE_BACKLIGHT_FAILED;
> >>>
> >>>
> >>>   i tried taking it out a couple of times and immediately got the same
> >>> i915-related problem so until i hear differently, the patch stays in.
> >>
> >> Thanks for the hint.  I tested the patch with 3.0.0-rc1 and
> >> unfortunately the symptoms remain the same.
> >>
> >> Meanwhile, I tested 2.6.39-gentoo as well and it also causes that
> >> problem.  So, this is not really a (new) 3.0.0-rc1 issue.
> >>
> >> Best regards,
> >>
> >> Dirk
> >
> > Your patch reminded me of another patch of Chris that caused problems
> > for several other people, but manually applied to the changed context in
> > 3.0.0-rc1 again works for me:
> >
> > --- linux-3.0-rc1/drivers/gpu/drm/i915/intel_bios.c     2011-05-30 02:43:36.000000000 +0200
> > +++ /usr/src/linux-3.0-rc1/drivers/gpu/drm/i915/intel_bios.c    2011-05-31 20:53:35.000000000 +0200
> > @@ -267,7 +267,7 @@
> >         case 4:
> >                 return alternate ? 100 : 96;
> >         default:
> > -               return alternate ? 100 : 120;
> > +               return alternate ? 120 : 100;
> >         }
> >  }
> >
> > The strange thing is that I am pretty sure that I did not have to modify
> > 2.6.28-gentoo{,-r4} what I at that time also reported here:
> > https://bugs.freedesktop.org/show_bug.cgi?id=31596
> 
> For completeness I want to report that I did a bisect and found out that
> the following commit seems to be the one that reintroduced the problem
> that I have to manually patch the kernel to avoid a blank screen
> (with backlight turned on) during boot:
> 
> 47a05eca72991039e788b25232061f9c9df9ec23 is the first bad commit
> commit 47a05eca72991039e788b25232061f9c9df9ec23
> Author: Jesse Barnes <jbarnes@...tuousgeek.org>
> Date:   Mon Feb 7 13:46:40 2011 -0800
> 
>     drm/i915: disable PCH ports if needed when disabling a CRTC
>     
>     Disable any PCH ports associated with a pipe when disabling it.  This
>     should prevent transcoder disable failures due to ports still being on.
>     
>     Signed-off-by: Jesse Barnes <jbarnes@...tuousgeek.org>
>     [ickle: introduce *_PIPE_ENABLED() macro]
>     Signed-off-by: Chris Wilson <chris@...is-wilson.co.uk>
> 
> :040000 040000 2c7c54cceb89821941943614cede86c4a2c2a8bc 9382527ee169beb54a10eb0afe8a69d418025c2e M      drivers

Just to confirm, does this patch also keep your screen enabled?

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_d
index 81a9059..ef41487 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1366,7 +1366,7 @@ static void intel_disable_pch_ports(struct drm_i915_privat
        val = I915_READ(reg);
        if (ADPA_PIPE_ENABLED(val, pipe))
                I915_WRITE(reg, val & ~ADPA_DAC_ENABLE);
-
+#if 0
        reg = PCH_LVDS;
        val = I915_READ(reg);
        if (LVDS_PIPE_ENABLED(val, pipe)) {
@@ -1374,7 +1374,7 @@ static void intel_disable_pch_ports(struct drm_i915_privat
                POSTING_READ(reg);
                udelay(100);
        }
-
+#endif
        disable_pch_hdmi(dev_priv, pipe, HDMIB);
        disable_pch_hdmi(dev_priv, pipe, HDMIC);
        disable_pch_hdmi(dev_priv, pipe, HDMID);

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