linux-kernel - Re: [PATCH 0/6] rtc: Fix problems with missing UIE irqs

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Message-ID: <87cyi798eo.fsf@geanix.com>
Date: Wed, 04 Dec 2024 09:09:19 +0100
From: Esben Haabendal <esben@...nix.com>
To: Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc: linux-rtc@...r.kernel.org,  linux-kernel@...r.kernel.org,
  linux-arm-kernel@...ts.infradead.org,  stable@...r.kernel.org,  Patrice
 Chotard <patrice.chotard@...s.st.com>
Subject: Re: [PATCH 0/6] rtc: Fix problems with missing UIE irqs

Esben Haabendal <esben@...nix.com> writes:

> This fixes a couple of different problems, that can cause RTC (alarm)
> irqs to be missing when generating UIE interrupts.
>
> The first commit fixes a long-standing problem, which has been
> documented in a comment since 2010. This fixes a race that could cause
> UIE irqs to stop being generated, which was easily reproduced by
> timing the use of RTC_UIE_ON ioctl with the seconds tick in the RTC.
>
> The last commit ensures that RTC (alarm) irqs are enabled whenever
> RTC_UIE_ON ioctl is used.
>
> The driver specific commits avoids kernel warnings about unbalanced
> enable_irq/disable_irq, which gets triggered on first RTC_UIE_ON with
> the last commit. Before this series, the same warning should be seen
> on initial RTC_AIE_ON with those drivers.

I don't have access to hardware using cpcap, st-lpc or tps6586x rtc
drivers, so I have not been able to test those 3 patches.

/Esben

> Signed-off-by: Esben Haabendal <esben@...nix.com>
> ---
> Esben Haabendal (6):
>       rtc: interface: Fix long-standing race when setting alarm
>       rtc: isl12022: Fix initial enable_irq/disable_irq balance
>       rtc: cpcap: Fix initial enable_irq/disable_irq balance
>       rtc: st-lpc: Fix initial enable_irq/disable_irq balance
>       rtc: tps6586x: Fix initial enable_irq/disable_irq balance
>       rtc: interface: Ensure alarm irq is enabled when UIE is enabled
>
>  drivers/rtc/interface.c    | 27 +++++++++++++++++++++++++++
>  drivers/rtc/rtc-cpcap.c    |  1 +
>  drivers/rtc/rtc-isl12022.c |  1 +
>  drivers/rtc/rtc-st-lpc.c   |  1 +
>  drivers/rtc/rtc-tps6586x.c |  1 +
>  5 files changed, 31 insertions(+)
> ---
> base-commit: 40384c840ea1944d7c5a392e8975ed088ecf0b37
> change-id: 20241203-rtc-uie-irq-fixes-f2838782d0f8
>
> Best regards,