[PATCH v2 5/5] rtc: rtc-cmos: Disable ACPI RTC event on removal

Rafael J. Wysocki
2022-11-09T12:15:51Z

Make cmos_do_remove() drop the ACPI RTC fixed event handler so as to
prevent it from operating on stale data in case the event triggers
after driver removal.

Fixes: 311ee9c151ad ("rtc: cmos: allow using ACPI for RTC alarm instead of HPET")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

v1 -> v2:
* Do not clear the driver data pointer (the driver core does that) (Andy)
* Adjust the code pattern in acpi_rtc_event_cleanup() (Andy)
* Drop inline from the full definition of acpi_rtc_event_cleanup()

---
drivers/rtc/rtc-cmos.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)

Index: linux-pm/drivers/rtc/rtc-cmos.c
===================================================================
--- linux-pm.orig/drivers/rtc/rtc-cmos.c
+++ linux-pm/drivers/rtc/rtc-cmos.c
@@ -798,6 +798,14 @@ static void acpi_rtc_event_setup(struct
acpi_disable_event(ACPI_EVENT_RTC, 0);
}

+static void acpi_rtc_event_cleanup(void)
+{
+ if (acpi_disabled)
+ return;
+
+ acpi_remove_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler);
+}
+
static void rtc_wake_on(struct device *dev)
{
acpi_clear_event(ACPI_EVENT_RTC);
@@ -884,6 +892,10 @@ static inline void acpi_rtc_event_setup(
{
}

+static inline void acpi_rtc_event_cleanup(void)
+{
+}
+
static inline void acpi_cmos_wake_setup(struct device *dev)
{
}
@@ -1138,6 +1150,9 @@ static void cmos_do_remove(struct device
hpet_unregister_irq_handler(cmos_interrupt);
}

+ if (!dev_get_platdata(dev))
+ acpi_rtc_event_cleanup();
+
cmos->rtc = NULL;

ports = cmos->iomem;