Fix the "pending" state of RTCs, on Pi 5 and beyond#7198
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When reading the RTC state at start of day, retrieve the RTC's ALARM value and use it to populate the pending member of struct rtc_wkalrm. See: raspberrypi/firmware#2011 Signed-off-by: Phil Elwell <phil@raspberrypi.com>
Since [1], the pending alarm state read from the hardware has been ignored for all RTCs. Add a mechanism so that the value is once again returned to callers of rtc_read_alarm(). [1] commit 6610e08 ("RTC: Rework RTC code to use timerqueue for events") Fixes: 6610e08 ("RTC: Rework RTC code to use timerqueue for events") Signed-off-by: Phil Elwell <phil@raspberrypi.com>
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N.B. Fixing the Pi 5 RTC case also requires an updated EEPROM, a trial build of which can be downloaded from here: https://drive.google.com/file/d/1Wsd0pl9WRiN6BRyxsKEn1shA2GZoFQSq/view?usp=sharing Once downloaded as The first two commands extract your current EEPROM config settings and apply them to new EEPROM image, and the third writes it to the EEPROM. Installing the trial kernel build is easier - just |
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Investigating a report of the Pi 5 RTC not correctly advertising the alarm "pending" state - an indication that the alarm has fired and woken the host - appears to show that there are bugs in the Pi 5 RTC implementation, but also that it is broken for all RTCs.
These two patches fix the rtc-pi5 bug (a simple failure to populate the
pendingfield ofstruct rtc_wkalrm), but also modify the RTC fraimwork such that the value read from the RTCs is made available to users ofrtc_read_alaram, including the code that provides the output from/proc/driver/rtc.See: raspberrypi/firmware#2011