Messages in this thread | | | Date | Mon, 6 Feb 2023 19:12:43 -0800 | Subject | Re: [PATCH v2 01/22] rtc: pm8xxx: fix set-alarm race | From | David Collins <> |
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On 2/2/23 07:54, Johan Hovold wrote: > Make sure to disable the alarm before updating the four alarm time > registers to avoid spurious alarms during the update.
What scenario can encounter a spurious alarm triggering upon writing the new alarm time inside of pm8xxx_rtc_set_alarm()?
> Note that the disable needs to be done outside of the ctrl_reg_lock > section to prevent a racing alarm interrupt from disabling the newly set > alarm when the lock is released.
What scenario shows the IRQ race issue that you mentioned? How does not protecting this register write with a lock avoid the race condition?
> Fixes: 9a9a54ad7aa2 ("drivers/rtc: add support for Qualcomm PMIC8xxx RTC") > Cc: stable@vger.kernel.org # 3.1 > Signed-off-by: Johan Hovold <johan+linaro@kernel.org> > --- > drivers/rtc/rtc-pm8xxx.c | 24 ++++++++++-------------- > 1 file changed, 10 insertions(+), 14 deletions(-)
Note that since locking is removed later in the patch series, my questions above are mainly for the sake of curiosity.
Reviewed-by: David Collins <quic_collinsd@quicinc.com>
Thanks, David
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