• Gabriele Mazzotta's avatar
    rtc: cmos: Clear ACPI-driven alarms upon resume · 983bf125
    Gabriele Mazzotta authored
    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.pdfSigned-off-by: default avatarGabriele Mazzotta <gabriele.mzt@gmail.com>
    Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@free-electrons.com>
    983bf125
rtc-cmos.c 32.1 KB