On 20/04/2018 13:59:28+0800, Zhang Rui wrote: > Hi, Alexandre > > On 四, 2018-04-19 at 16:05 +0200, Alexandre Belloni wrote: > > Hi, > > > > > > On 26/03/2018 21:58:01+0800, Zhang Rui wrote: > > > > > > It's found that the HPET timer prevents the platform from entering > > > Low Power S0 on some new Intel platforms. > > > > > > This means that > > > 1. users can still use RTC wake Alarm for suspend-to-idle, but the > > > system > > > never enters Low Power S0, which is a waste of power. > > > or > > > 2. if users want to put the system into Low Power S0, they can not > > > use > > > RTC as the wakeup source. > > > > > > To fix this, we need to stop using the HPET timer for wake alarm. > > > But disabling CONFIG_HPET_EMULATE_RTC is not an option because HPET > > > emulates PIT at the same time, and this is needed on some of these > > > platforms. > > > > > > Thus, introduce a new mode (use_acpi_alarm) to the rtc_cmos driver, > > > so that, even with CONFIG_HPET_EMULATE_RTC enabled, it's still > > > possible to > > > use ACPI SCI for RTC Alarm, including UIE/AIE/wkalrm, instead of > > > HPET. > > > > > > Only necessary changes are made for the new "use_acpi_alarm" mode, > > > including > > > 1. drop all the calls to HPET emulation code, including the HPET > > > irq > > > handler for rtc interrupt. > > > 2. enabling/disabling ACPI RTC Fixed event upon RTC UIE/AIE > > > request. > > > 3. acknowledge the RTC Alarm in ACPI RTC Fixed event handler. > > > > > > There is no functional change made in this patch if the new mode is > > > not > > > enabled. > > > > > > Note: this "use_acpi_alarm" mode is made based on the assumption > > > that > > > ACPI RTC Fixed event is reliable both at runtime and during system > > > wakeup. > > > And this has been verified on a couple of platforms I have, > > > including > > > a MS Surface Pro 4 (SKL), a Lenovo Yoga 900 (SKL), and a HP 9360 > > > (KBL). > > > > > > Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx> > > > --- > > > drivers/rtc/rtc-cmos.c | 111 +++++++++++++++++++++++++++++++++++ > > > -------------- > > > 1 file changed, 80 insertions(+), 31 deletions(-) > > > > > I've applied the series but it didn't apply cleanly, please check > > https://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux.git/lo > > g/?h=rtc-next > > > Yes, I noticed this conflict as well. > I have rebased it on top of -rc1 and it is under testing right now. > I will rebase on your tree and resend. > Rebasing on top of -rc1 is sufficient, I'm already carrying your patches now so they are part of linux-next early in the cycle. -- Alexandre Belloni, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering https://bootlin.com
