cvs commit: src/sys/kern subr_power.c

Scott Long scottl at
Wed Nov 9 13:56:06 GMT 2005

Bruce Evans wrote:
> On Wed, 9 Nov 2005, Warner Losh wrote:
>>  Modified files:
>>    sys/kern             subr_power.c
>>  Log:
>>  Kick off the suspend sequence from the keyboard in a SWI rather than
>>  in the hardware interrupt context (even if it is likely just an
>>  ithread).  We don't document that suspend/resume routines are run from
>>  such a context and some of the things that happen in those routines
>>  aren't interrupt safe.  Since there's no real need to run from that
>>  context, this restores assumptions that suspend routines have made.
>>  This fixes Thierry Herbelot's 'Trying to sleep while sleeping is
>>  prohibited' problem.
> Er, SWIs are interrupts too.  Trying to sleep in a SWI handler should
> cause the same message.  This commit uses the general taskqueue SWI
> handler.  taskqueue(9) implicitly says that only the taskqueue thread
> handler can sleep (it gives malloc(M_WAITOK) as an example of something
> that can only be done in thread context).
> Bruce

You're right, but sleeping in SWI's has never been enforced.  CAM relies 
on it, for better or worse, and until that's fixed it's pointless to
start enforcing it.


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