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

From: Pratyush Anand
Date: Mon Jun 27 2016 - 00:55:28 EST


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