cvs commit: src/sys/kern subr_power.c

John Baldwin jhb at
Wed Nov 9 15:43:43 GMT 2005

On Wednesday 09 November 2005 08:56 am, Scott Long wrote:
> 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.

Well, I don't think we should knowingly go around adding more instances of 
it. :)  In this case it is really easy to just use taskqueue_thread rather 
than taskqueue_swi.

John Baldwin <jhb at>  <><
"Power Users Use the Power to Serve"  =

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