On 21/02/17 16:32, Geert Uytterhoeven wrote: > Hi Sudeep, > > On Tue, Feb 21, 2017 at 12:14 PM, Sudeep Holla <sudeep.holla@xxxxxxx> wrote: >> On 21/02/17 11:07, Pavel Machek wrote: >>>> Enable support for "shallow" suspend mode, also known as "Standby" or >>>> "Power-On Suspend". >>>> >>>> As secondary CPU cores are taken offline, "shallow" suspend mode saves >>>> slightly more power than "s2idle", but less than "deep" suspend mode. >>>> However, unlike "deep" suspend mode, "shallow" suspend mode can be used >>>> regardless of the presence of support for PSCI_SYSTEM_SUSPEND, which is >>>> an optional API in PSCI v1.0. >>> >>> If system supports "shallow" suspend, why does not PSCI implement it? >> >> Yes it can, and IIUC it already does on this platform with CPU_SUSPEND. >> All it now needs is just to use existing "freeze" suspend mode in Linux. > > How can Linux know if using "deep" suspend will allow to wake-up the system > according to configured wake-up sources, or not? > I am not sure if we have such selective configuration of wakeup source implemented in Linux. ACPI specification has some provisions where each device can state if it can specify device state in each system sleeping state that can wake the system. DT has no mechanism today to express this relations. I had brought up this discussion in plumbers(2015). Refer slide 7 in [0] And the way you are trying to do that is not correct IMO especially making it just PSCI specific. > Note that "it will not, ever" is an accepted answer. > IIUC, it's not implemented today. I can't talk about future ;), but your proposal is horrible hack. -- Regards, Sudeep [0] https://linuxplumbersconf.org/2015/ocw//system/presentations/3051/original/wakeup_config.pdf -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
