On Dec 7, 2009, at 3:41 PM, "Rafael J. Wysocki" <rjw@xxxxxxx> wrote: > On Sunday 06 December 2009, you wrote: >> Hi, I have a completly unsolicited patch that I figured I should >> run past you >> before proceeding to embarrass myself on lkml, as there does not >> seem to be >> a linux kernel related mailing list more dedicated to power >> management. > > There is a pm list, <linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx>. Please > post patches > to this list in the future rather than to me directly, because I > have rather > limited patch-reviewing capacity. Yes, I found it shortly after sending you the patch. > >> This patch just adds /sys/power/last_state, which will make my job >> making >> pm-utils more robust in the face of suspend or hibernate failure a >> little >> easier. >> >> last_state will contain the last suspend state the kernel >> successfully >> resumed from. This sysfs interface was added so that userspace tools >> (such as pm-utils) can determine whether the last requested power >> management >> operation succeeded or failed without having to listen to uevents >> (a tricky >> proposition when you are written in shell script), or parse the >> kernel event >> log (annoying when most of the time things will succeed anyways). > > What exactly do you need the previous state for? So that pm-utils could see whether or not suspend/hibernate worked or just returned due to a failure of some sort. > > Can't you just use the error code returned by "echo mem > /sys/power/ > state"? I can, now that I know about it - I did not see anything about error codes when scanning the documentation. > > Rafael > _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
