Re: ACPI global lock macros
From: Paul Menage
Date: Tue Dec 09 2003 - 04:54:38 EST
Arjan van de Ven wrote:
maybe the odd thing is that it exists at all?
(eg why does ACPI need to have it's own locking primitives...)
Because the ACPI spec defines its own locking protocol for
synchronization between the OS and the BIOS.
... which can't be written based on linux locks ?
I assume (hope!) there's already a higher-level linux lock serializing
access to acpi_acquire_global_lock() although I've not delved deeply
into the code. This is the lock described on p112 of
http://www.acpi.info/DOWNLOADS/ACPIspec-2-0c.pdf, which has the
semantics that if the OS wants to take the lock while the BIOS holds it,
it sets a bit and waits for an interrupt from the BIOS. I don't see that
it could be naturally implemented using a linux lock.
Paul
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