RE: [linux-pm] [BUG] sleeping function called from invalid context during resume

[Brown, Len]

>... a similar fix needs to be made in
drivers/acpi/osl.c:acpi_os_wait_semaphore().
>If interrupts are disabled the timeout argument should be set to 0, so
that the 
>routine will call down_trylock() instead of down() or
schedule_timeout_interruptible().

We used to have a hack in acpi_os_wait_semaphore():

if (in_atomic())
	timeout = 0;

But we deleted it upon ACPICA 20060608 when the
ACPICA locks that were used at interrupt-time were
converted to be Linux spin-locks.

Now it is still conceivable that during resume before interrutps are
re-enabled,
the PCI interrupt link devices run AML and go to acquire an AML mutex
with
a timeout.  However, we are single threaded at that point, so it isn't
possible for them to acquire the mutex -- timeout or not.

I don't like the looks of the "workaround" above -- it makes the code
confusing.

I'd be open to putting a BUG_ON() in the sleep case if interrupts are
not enabled.

Is there another case that you can think of?

-Len
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