Re: Bisected 3.12.0-rc1 Laptop screen goes blank during kernelboot

[Aaron Lu <aaron.lwe@gmail.com>]

Add linux-pm.

-Aaron

On 09/21/2013 01:13 AM, Hans de Bruin wrote:
> During boot time my laptop screen goes blank when de kernel switches the 
> screen to another resolution. The backlight is on. Eventually a kde 
> login box appears out of the blackness. Swiching to a lower resolution 
> gives me a black screen again. After testing the 
> intel-gfx@lists.freedesktop.org developers test-tree problem less they 
> sugested a bisect. That bisect ended in:
> 
> 
> commit 137b944e100278d696826cf25c83014ac17473fe
> Author: Daniel Lezcano <daniel.lezcano@linaro.org>
> Date:   Wed Jun 12 15:08:48 2013 +0200
> 
>    cpuidle: Make it clear that governors cannot be modules
> 
>    cpufreq governors are defined as modules in the code, but the Kconfig
>    options do not allow them to be built as modules.  This is not really
>    a problem, but the cpuidle init ordering is: the cpuidle init
>    functions (framework and driver) and then the governors.  That leads
>    to some weirdness in the cpuidle framework.
> 
>    Namely,  cpuidle_register_device() calls cpuidle_enable_device() which
>    fails at the first attempt, because governors have not been registered
>    yet.  When a governor is registered, the framework calls
>    cpuidle_enable_device() again which runs __cpuidle_register_device()
>    only then.  Of course, for that to work, the cpuidle_enable_device()
>    return value has to be ignored by cpuidle_register_device().
> 
>      Instead of having this cyclic call graph and relying on a positive
>      side effects of the hackish back and forth cpuidle_enable_device()
>      calls it is better to fix the cpuidle init ordering.
> 
>      To that end, replace the module init code with postcore_initcall()
>      so we have:
> 
>       * cpuidle framework : core_initcall
>       * cpuidle governors : postcore_initcall
>       * cpuidle drivers   : device_initcall
> 
>      and remove the corresponding module exit code as it is dead anyway
>      (governors can't be built as modules).
> 
>      [rjw: Changelog]
>      Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
>      Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> :040000 040000 45e7cb28411864c00b62296a7ff239f9f139d5d9 
> 86a36b01dee52a77cfbab41a973b7a2bfa44ce34 M      drivers
> 
> 
> 
> Reverting it makes the problem go away.
>