Kernel panic when unpluggin AC adaptor

[David DEMELIER]

2010/6/11 John Baldwin <jhb at freebsd.org>:
> On Friday 11 June 2010 6:27:48 am Giovanni Trematerra wrote:
>> On Thu, Jun 10, 2010 at 10:58 PM, Giovanni Trematerra
>> <giovanni.trematerra at gmail.com> wrote:
>> > On Tue, May 4, 2010 at 6:35 PM, David DEMELIER <demelier.david at gmail.com>
> wrote:
>> >> Good news ! It worked, check the picture here :
>> >>
>> >> http://img63.imageshack.us/img63/4244/dsc00361g.jpg
>> >>
>> >
>> > Into the file sys/dev/acpica/acpi_cpu.c at the end of acpi_cpu_notify
>> > (a per cpu notification handler), called when _CST objects changing,
>> > global cpu_cx_count is set to the greatest value of all sc->cpu_cx_count
>> > per-cpu variables. That could result in a panic as David reported,
>> > because that lets to invoke acpi_cpu_global_cx_lowest_sysctl from
>> > /etc/rc.d/power_profile, when AC adapter is unplugged,  with a value
>> > that not all the CPUs could handle in the acpi_cpu_idle.
>> > The patch also change global cpu_cx_lowest according to new value of
>> > global cpu_cx_count if needed.
>> >
>> > David Demelier made a great work to test every patch I sent him
>> > to identify the source of the problem.
>> >
>> > Please, let me know your comments and possibly commit the patch
>> > if you think is good enough.
>>
>> As jhb@ pointed me out in private with the previous patch a CPU could
>> never enter in the
>> lowest Cx-state even if it gained.
>> So I'd like to propose this new solution.
>> When hw.acpi.cpu.cx_lowest sysctl is set, the global handler in
>> sys/dev/acpi_cpu.c
>> will set the greatest sc->cpu_cx_lowest value supported by the CPU and
>> not the same
>> value for all CPUs.
>> Later, when CPU, possibly gain new Cx-states, the acpi_cpu_notify
>> handler will set
>> sc->cpu_cx_lowest accordingly with global cx_lowest and the Cx-states
>> supported by
>> the CPU.
>>
>> Now I think that /etc/rc.d/power_profile script has a problem but that
>> is a different story.
>> The script select the lowest_value only querying cx-states of the dev.cpu.0.
>> If different CPUs may have different Cx-states, the script should use
>> as lowest_value the
>> lowest value between all the CPUs.
>
> Yes.
>
>> Please, let me know your comments and possibly commit the patch
>> if you think is good enough.
>
> I think this is a good compromise for now.
>
> --
> John Baldwin
>

Thanks for Giovanni's patience and work, he made a lot of research to
solve this little problem :-).

Is there a chance that this patch appears in 8.1-RELEASE ?

Kind regards.

-- 
Demelier David