notebook freezes

[Bruce Evans]

On Wed, 7 Mar 2007, John Baldwin wrote:

> On Wednesday 07 March 2007 00:14, Bruce Evans wrote:
>> I forgot to ask about the problem of interrupts racing with resume.
>> What stops an interrupt occurring before the resume methods (the device
>> method and all the ones above it) complete?  I don't know of any locking
>> to prevent this or any way to detect this short of checking for magic
>> garbage in device registers that have garbage in them because the
>> registers are unmapped or just clobbered.  Can suspend happen
>> asynchronously, so that it is possible for resume to deadlock on a
>> resource locked by somthing which was interrupted for the suspend?
>
> I don't think there is stuff in there to protect against locks being held.
> However, each device is supposed to turn its device off in it's
> device_suspend() method and then turn it back on in device_resume() which
> should resolve problems with garbage registers and spurious interrupts.

pmtimer doesn't do this of course.  Turning of RTC interrupts is easy,
but turning off i8254 interrupts seems to require bus_teardown_intr().

Bruce