> > The FADT also exposes whether the RTC can wake from S4. You may have > > noticed that my rtc-cmos patch #3 exported the relevant FADT info > > to the RTC device using platform_data, but the S4 wake capability flag > > isn't useful for anything on today's Linux. > > Isn't useful in what way? It'd be helpful for userspace to know that now > that we're actually using S4 for swsusp, but I understand that it might > not fit into the current API terribly well. In that current API there's no way to tell anything at all about the target system state inside a driver's suspend() method. So if there were some characteristic of S4 (or S3 etc) that mattered to the driver (it should test for the attribute, not S4/etc since S4 is ACPI-specific) the driver couldn't do anything about it ... so as I said, not useful. - Dave
