Re: [PATCH v2] leds: heartbeat: stop on shutdown

Shuah Khan
2012-04-24T17:31:54Z

On Tue, 2012-04-24 at 19:27 +0200, Alexander Holler wrote:
> Am 24.04.2012 19:00, schrieb Shuah Khan:
> > On Tue, 2012-04-24 at 18:32 +0200, Alexander Holler wrote:
> >> Am 24.04.2012 17:24, schrieb Shuah Khan:
> >>> On Tue, 2012-04-24 at 17:07 +0200, Alexander Holler wrote:
> >>>> A halted kernel should not show a heartbeat.
> >>>>
> >>>> Signed-off-by: Alexander Holler <holler@ahsoftware.de>
> >>>> ---
> >>>> drivers/leds/ledtrig-heartbeat.c | 18 +++++++++++++++++-
> >>>> 1 files changed, 17 insertions(+), 1 deletions(-)
> >>>>
> >>>> diff --git a/drivers/leds/ledtrig-heartbeat.c b/drivers/leds/ledtrig-heartbeat.c
> >>>> index 759c0bb..1c05bd9 100644
> >>>> --- a/drivers/leds/ledtrig-heartbeat.c
> >>>> +++ b/drivers/leds/ledtrig-heartbeat.c
> >>>> @@ -18,6 +18,7 @@
> >>>> #include <linux/timer.h>
> >>>> #include <linux/sched.h>
> >>>> #include <linux/leds.h>
> >>>> +#include <linux/reboot.h>
> >>>> #include "leds.h"
> >>>>
> >>>> struct heartbeat_trig_data {
> >>>> @@ -101,13 +102,28 @@ static struct led_trigger heartbeat_led_trigger = {
> >>>> .deactivate = heartbeat_trig_deactivate,
> >>>> };
> >>>>
> >>>> +static int heartbeat_reboot_notifier(struct notifier_block *nb,
> >>>> + unsigned long code, void *unused)
> >>>> +{
> >>>> + led_trigger_unregister(&heartbeat_led_trigger);
> >>>> + return NOTIFY_DONE;
> >>>> +}
> > I am sorry I didn't catch this the last time. Do you need to call
> > unregister here? Looks like trigger is going away with a registered
> > reboot notifier. Might be fine, since reboot is going to happen.
>
> That unregister is the whole reason of the patch because it disables all
> running heartbeats on reboot/shutdown. ;)

Sorry I should have been clear about which unregister. I meant
unregister_reboot_notifier()
>
> I still wonder why the timers are running after a kernel halted (so the
> heardbeat was still alive), but there might be a good reason not just to
> disable all running timers unconditionally on shutdown.
>
> Regards,
>
> Alexander
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