Re: + rtc-disable-hpet-emulation-on-suspend.patch added to -mm tree

[Ingo Molnar <mingo@elte.hu>]

* akpm@linux-foundation.org <akpm@linux-foundation.org> wrote:

> ------------------------------------------------------
> Subject: rtc: disable hpet emulation on suspend
> From: Maxim Levitsky <maximlevitsky@gmail.com>
> 
> I noticed that rtc wont generate interrupts after a resume from disk.
> Here hpet rtc emulation is used.
> 
> Problem is that rtc hpet comparator, isn't reinitialized after resume.
> Easiest way to solve this, is always mask all hpet interrupts on suspend
> This is triggered, when suspending with alarm set.
> 
> 
> Otherwise, hpet driver will think it doesn't need to reinitialize
> the rtc comparator, thus rtc interrupts won't work.
> 
> This emulation isn't need for wakealarm.

> -		hpet_mask_rtc_irq_bit(mask);
>  
> +		/* shut down hpet emulation - we don't need it for alarm */
> +		hpet_mask_rtc_irq_bit(RTC_PIE|RTC_AIE|RTC_UIE);
>  		cmos_checkintr(cmos, tmp);

Would be nice to also unconditionally reinitialize the hpet/rtc after 
resume - regardless of what state we left it in.

Also, are you sure this does not break things like 
CONFIG_PM_TEST_SUSPEND=y which rely on wakealarm?

	Ingo