On Sunday 30 September 2007, you wrote:
>
> > kernel_restart() seems appropriate for that.
>
> Now a comment to this one says:
>
> * This is not safe to call in interrupt context.
>
> and AFAIU, this is called from an interrupt. Am I missing anything or
> would this be wrong to call kernel_restart() here?
It should be called through a workqueue, afaics, do avoid calling
a sleeping notifier from an interrupt.
> > > +static irqreturn_t beat_reset_event(int virq, void *arg)
> > > +{
> > > + printk(KERN_DEBUG "Beat: reset button pressed\n");
> > > + beat_pm_poweroff_flag = 0;
> > > + if (kill_cad_pid(SIGINT, 1)) {
> > > + /* Just in case killing init process failed */
> > > + beat_restart(NULL);
> > > + }
> > > + return IRQ_HANDLED;
> > > +}
> >
> > same here, except calling kernel_halt() in the end.
>
> kernel_halt() doesn't have a similar comment, but it does call the
> kernel_shutdown_prepare() too, so, seems like it should not be called from
> an interrupt either?
yes
> Now, another question, is it generally good to hard-wire "reset" and
> "power-off" buttons in the kernel? Isn't it better to just register them
> as input event sources and let userspace (power-management daemon) decide
> what to do with them? Like poweroff / reboot / suspend / hibernate / ...
Tough question. I can see arguments for either way, but I guess I'd tend
to handling it in the kernel, choosing simplicity over consistency.
Arnd <><
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