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SubjectRe: [PATCH v3 1/2] rtc-cmos: Clear ACPI-driven alarms upon resume
Hi Gabriele,

Thanks for your persistence! Both patches look good. Can you fix the
build issues reported by kbuild?

On 14/09/2016 at 21:08:40 +0200, Gabriele Mazzotta wrote :
> Currently ACPI-driven alarms are not cleared when they wake the
> system. As consequence, expired alarms must be manually cleared to
> program a new alarm. Fix this by correctly handling ACPI-driven
> alarms.
>
> More specifically, the ACPI specification [1] provides for two
> alternative implementations of the RTC. Depending on the
> implementation, the driver either clear the alarm from the resume
> callback or from ACPI interrupt handler:
>
> - The platform has the RTC wakeup status fixed in hardware
> (ACPI_FADT_FIXED_RTC is 0). In this case the driver can determine
> if the RTC was the reason of the wakeup from the resume callback
> by reading the RTC status register.
>
> - The platform has no fixed hardware feature event bits. In this
> case a GPE is used to wake the system and the driver clears the
> alarm from its handler.
>
> [1] http://www.acpi.info/DOWNLOADS/ACPI_5_Errata%20A.pdf
>
> Signed-off-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
> ---
> drivers/rtc/rtc-cmos.c | 32 ++++++++++++++++++++++++++++++++
> 1 file changed, 32 insertions(+)
>
> diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
> index 1dec52f..6042257 100644
> --- a/drivers/rtc/rtc-cmos.c
> +++ b/drivers/rtc/rtc-cmos.c
> @@ -939,6 +939,22 @@ static int cmos_resume(struct device *dev)
> tmp &= ~RTC_AIE;
> hpet_mask_rtc_irq_bit(RTC_AIE);
> } while (mask & RTC_AIE);
> +
> + if ((tmp & RTC_AIE) &&
> + !(acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)) {
> + acpi_status status;
> + acpi_event_status rtc_status;
> +
> + status = acpi_get_event_status(ACPI_EVENT_RTC,
> + &rtc_status);
> + if (ACPI_FAILURE(status)) {
> + dev_err(dev, "Could not get RTC status\n");
> + } else if (rtc_status & ACPI_EVENT_FLAG_SET) {
> + tmp &= ~RTC_AIE;
> + CMOS_WRITE(tmp, RTC_CONTROL);
> + rtc_update_irq(cmos->rtc, 1, mask);
> + }
> + }
> }
> spin_unlock_irq(&rtc_lock);
>
> @@ -976,6 +992,22 @@ static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
> static u32 rtc_handler(void *context)
> {
> struct device *dev = context;
> + struct cmos_rtc *cmos = dev_get_drvdata(dev);
> + unsigned char rtc_control;
> + unsigned char rtc_intr;
> +
> + spin_lock_irq(&rtc_lock);
> + if (!cmos_rtc.suspend_ctrl)
> + rtc_control = cmos_rtc.suspend_ctrl;
> + else
> + rtc_control = CMOS_READ(RTC_CONTROL);
> + if (rtc_control & RTC_AIE) {
> + cmos_rtc.suspend_ctrl &= ~RTC_AIE;
> + CMOS_WRITE(rtc_control, RTC_CONTROL);
> + rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
> + rtc_update_irq(cmos->rtc, 1, rtc_intr);
> + }
> + spin_unlock_irq(&rtc_lock);
>
> pm_wakeup_event(dev, 0);
> acpi_clear_event(ACPI_EVENT_RTC);
> --
> 2.9.3
>

--
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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