Re: [PATCH v2 1/2] rtc-cmos: Ensure no expired alarm is left enabled after resume

[Gabriele Mazzotta]

2016-09-06 0:26 GMT+02:00 Alexandre Belloni
<alexandre.belloni@xxxxxxxxxxxxxxxxxx>:
> Hi
>
> On 01/09/2016 at 00:58:59 +0200, Gabriele Mazzotta wrote :
>>  static int cmos_resume(struct device *dev)
>>  {
>>       struct cmos_rtc *cmos = dev_get_drvdata(dev);
>>       unsigned char tmp;
>> +     bool is_wkalrm_expired;
>>
>>       if (cmos->enabled_wake) {
>>               if (cmos->wake_off)
>> @@ -913,6 +935,8 @@ static int cmos_resume(struct device *dev)
>>               cmos->enabled_wake = 0;
>>       }
>>
>> +     is_wkalrm_expired = cmos_is_wkalrm_expired(dev);
>> +
>>       spin_lock_irq(&rtc_lock);
>>       tmp = cmos->suspend_ctrl;
>>       cmos->suspend_ctrl = 0;
>> @@ -939,6 +963,17 @@ static int cmos_resume(struct device *dev)
>>                       tmp &= ~RTC_AIE;
>>                       hpet_mask_rtc_irq_bit(RTC_AIE);
>>               } while (mask & RTC_AIE);
>> +
>> +             /*
>> +              * If RTC_AIE is set and we have an alarm set to go off in the
>> +              * past, then the BIOS woke the system when the alarm went off
>> +              * and we now have to clear it.
>> +              */
>> +             if ((tmp & RTC_AIE) && is_wkalrm_expired) {
>
> Is there any issue dropping is_wkalrm_expired and calling
> cmos_is_wkalrm_expired() here? That would avoid calling
> cmos_is_wkalrm_expired on each wakeup.

Yes, get_rtc_time() (cmos_read_time()) tries to aquire rtc_lock.

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