Re: [PATCH 1/3] acpi: add real mutex function calls

Andi Kleen
2008-07-21T09:17:26Z

Peter Zijlstra wrote:
> On Mon, 2008-07-21 at 09:51 +0800, Zhao Yakui wrote:
>> On Sat, 2008-07-19 at 11:16 -0700, Daniel Walker wrote:
>>> Instead of re-using semaphores for the mutex operation, I've
>>> added usage of the kernel mutex for the os mutex implementation.
>>>
>> What is the advantage that the kernel mutex is used for the ACPI mutex
>> implementation instead of using semaphore?
>> And it seems that too much ACPICA source code is touched.
>
> You get help from lockdep, and also our goal is to fully eradicate
> semaphore usage.

Issue is that ACPICA is shared with other OS source code and to replace
a major interface like this would mean replacing it for everyone. It
might end up with ACPICA just reimplementing a semaphore like wrapper if
semaphores really go away, but I don't really see that coming anyways.

-Andi