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@xxxxxxxxxxxxxxxxxxxxx developers test-tree problem less they
sugested a bisect. That bisect ended in:
commit 137b944e100278d696826cf25c83014ac17473fe
Author: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
:040000 040000 45e7cb28411864c00b62296a7ff239f9f139d5d9
86a36b01dee52a77cfbab41a973b7a2bfa44ce34 M drivers
Reverting it makes the problem go away.
--
Hans
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