Jesse Barnes | 12 Jan 19:36 2012

Re: I915 regression : black screen at boot / Sandybridge Mobile (GT2)

On Thu, 12 Jan 2012 19:29:37 +0100
Vincent Vanackere <vincent.vanackere <at> gmail.com> wrote:

> Hi,
> 
> I when trying to run any recent (>= 3.2) kernel on my laptop (a Thinkpad
> L520), I get a black screen at boot and the screen stays black (the rest of
> the system seems fine and e.g. I can log from ssh).
> This is a regression since kernel 3.1 was working fine... I just bisected
> the problem and if I did no mistake the misbehavior was caused by the
> following commit :
> 
> ----------------------------------
> 4b645f14021871e06ce96c359bbdf0b48248c26e is the first bad commit
> commit 4b645f14021871e06ce96c359bbdf0b48248c26e
> Author: Jesse Barnes <jbarnes <at> virtuousgeek.org>
> Date:   Wed Oct 12 09:51:31 2011 -0700
> 
>     drm/i915: add PLL sharing support to handle 3 pipes
> 
>     Add two new fields to the intel_crtc struct for 3 pipe support: no_pll
>     and use_pll_a.  The no_pll field is only set on the 3rd pipe to indicate
>     that it doesn't have a PLL of its own and so shouldn't try to write the
>     main PLL regs.  The use_pll_a field controls which PLL pipe 3 will
>     share, A or B.  The core code will try to share PLLs with whichever pipe
>     has the same timings, rejecting the mode set if none is found.  This
>     means that pipe 3 must always be set after one of the other pipes has
>     been configured with real PLL settings.
> 
>     Signed-off-by: Jesse Barnes <jbarnes <at> virtuousgeek.org>
(Continue reading)

Stefan G. Weichinger | 12 Jan 20:05 2012
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Re: I915 regression : black screen at boot / Sandybridge Mobile (GT2)

Am 12.01.2012 19:36, schrieb Jesse Barnes:
> On Thu, 12 Jan 2012 19:29:37 +0100
> Vincent Vanackere <vincent.vanackere <at> gmail.com> wrote:
> 
>> Hi,
>>
>> I when trying to run any recent (>= 3.2) kernel on my laptop (a Thinkpad
>> L520), I get a black screen at boot and the screen stays black (the rest of
>> the system seems fine and e.g. I can log from ssh).

I just subscribed to this list as I face exactly the same problem.
I'll be happy to provide any logs or infos ...

Stefan
Markus Lux | 19 Jan 17:01 2012
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Re: I915 regression : black screen at boot / Sandybridge Mobile (GT2)

I have the same problem with my L520, too.

I also have an external VGA Monitor connected - I got graphical output there an
can work with it normally. But my laptop screen stays black all the time. Also
after rebooting the machine, sometimes the laptop screens brightness is darker
than it should be at boot time (which I find quite weird).
I use Arch Linux, Package linux-3.2.1-1
Daniel Vetter | 19 Jan 17:11 2012
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Re: I915 regression : black screen at boot / Sandybridge Mobile (GT2)

On Thu, Jan 19, 2012 at 04:01:43PM +0000, Markus Lux wrote:
> I have the same problem with my L520, too.
> 
> I also have an external VGA Monitor connected - I got graphical output there an
> can work with it normally. But my laptop screen stays black all the time. Also
> after rebooting the machine, sometimes the laptop screens brightness is darker
> than it should be at boot time (which I find quite weird).
> I use Arch Linux, Package linux-3.2.1-1

Can you try the latest drm-intel-fixes branch from
https://git.kernel.org/?p=linux/kernel/git/keithp/linux.git;a=summary
please? That contains the patch discussed here which hopefully fixes this
issue for you, too.

Thanks, Daniel
--

-- 
Daniel Vetter
Mail: daniel <at> ffwll.ch
Mobile: +41 (0)79 365 57 48

Gmane