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Re: [PATCH RFC 0/2] rtc-cmos: Workaround unwanted interrupt generation

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  Re: [PATCH RFC 0/2] rtc-cmos: Workaround unwanted interrupt  generation Pratyush Anand <panand@redhat.com> - 2016-06-27 07:00 +0200
    Re: [PATCH RFC 0/2] rtc-cmos: Workaround unwanted interrupt  generation Pratyush Anand <panand@redhat.com> - 2016-07-04 18:30 +0200

#1431713 — Re: [PATCH RFC 0/2] rtc-cmos: Workaround unwanted interrupt generation

On 21/06/2016:10:25:34 AM, Pratyush Anand wrote:
> We have observed on few machines with rtc-cmos device that
> hpet_rtc_interrupt() is called before cmos_do_probe() could call
> hpet_rtc_timer_init(). It has not been observed during normal boot/reboot
> of machines. It *sometime* happens when system is booted with kdump
> secondary kernel. So, neither hpet_default_delta nor hpet_t1_cmp is
> initialized by the time interrupt is raised in the given situation.
> Therefore while loop of hpet_cnt_ahead() in hpet_rtc_timer_reinit() never
> completes. This leads to "NMI watchdog: Watchdog detected hard LOCKUP on
> cpu 0".
> 
> I am still clueless, how can an interrupt be raised before RTC is enabled.
> But i do not have any idea about this device, so I am putting this patch as
> RFC to get feedback from hpet/rtc-cmos developer. I am sure there would be
> some better solution than this.

Do you think that if I improve commit log of patches as pointed by Thomas and
send a formal version of these patches, then they should acceptable to upstream?

Thanks

~Pratyush
> 
> 
> 
> Pratyush Anand (2):
>   rtc/hpet: Factorize hpet_rtc_timer_init()
>   rtc/rtc-cmos: Initialize software counters before irq is registered
> 
>  arch/x86/include/asm/hpet.h |  2 ++
>  arch/x86/kernel/hpet.c      | 41 +++++++++++++++++++++++++++++++++++------
>  drivers/rtc/rtc-cmos.c      | 13 ++++++++++++-
>  3 files changed, 49 insertions(+), 7 deletions(-)
> 
> -- 
> 2.5.5

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#1436374

On 27/06/2016:10:19:07 AM, Pratyush Anand wrote:
> On 21/06/2016:10:25:34 AM, Pratyush Anand wrote:
> > We have observed on few machines with rtc-cmos device that
> > hpet_rtc_interrupt() is called before cmos_do_probe() could call
> > hpet_rtc_timer_init(). It has not been observed during normal boot/reboot
> > of machines. It *sometime* happens when system is booted with kdump
> > secondary kernel. So, neither hpet_default_delta nor hpet_t1_cmp is
> > initialized by the time interrupt is raised in the given situation.
> > Therefore while loop of hpet_cnt_ahead() in hpet_rtc_timer_reinit() never
> > completes. This leads to "NMI watchdog: Watchdog detected hard LOCKUP on
> > cpu 0".
> > 
> > I am still clueless, how can an interrupt be raised before RTC is enabled.
> > But i do not have any idea about this device, so I am putting this patch as
> > RFC to get feedback from hpet/rtc-cmos developer. I am sure there would be
> > some better solution than this.
> 
> Do you think that if I improve commit log of patches as pointed by Thomas and
> send a formal version of these patches, then they should acceptable to upstream?

A gentle reminder for your comment/feedback :-)

~Pratyush

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