git: powerd: Wait hw.acpi.cpu.px_dom* sysctl to be created by kernel

Sepherosa Ziehau sepherosa at
Sun May 15 18:33:07 PDT 2011

On Mon, May 16, 2011 at 5:54 AM, Thomas Nikolajsen
<thomas.nikolajsen at> wrote:
>>commit 8db2b57665ff7b54aeb3592197587759b5a7eb5e
>>Author: Sepherosa Ziehau <sephe at>
>>Date:   Sun Apr 17 15:00:54 2011 +0800
>>    powerd: Wait hw.acpi.cpu.px_dom* sysctl to be created by kernel
>>    Since hw.acpi.cpu.px_dom* creation is queued into ACPI taskqueue
>>    and ACPI taskqueue is shared across various ACPI modules, any delay
>>    in other modules may cause hw.acpi.cpu.px_dom* to be created at
>>    quite a later time (e.g. cmbat module's task could take quite a lot
>>    of time).
> A timeout would be nice, for now powerd(8) will wait indefinite
> if hw.acpi.cpu.px_dom* isn't created on system.
> How long timeout is reasonable? Maybe 5 minutes; or 1 minute; or ..?

Hmm, I think powerd will daemonize itself before endless waiting, so
it should not choke the booting process at least.  Well, as about the
timeout, I didn't measure; it mainly depends on how much time the
tasks before pstate consumed (e.g. battery detection failure could
take quite some time).

Best Regards,

Tomorrow Will Never Die

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