Hi. On Mon, 2009-02-02 at 10:09 -0500, Alan Stern wrote: > On Mon, 2 Feb 2009, Uli Luckas wrote: > > > On Sunday, 1. February 2009, Alan Stern wrote: > > > Early-suspend seems to be a completely different matter. In fact it > > > isn't a suspend state at all, as far as I understand it. It's more > > > like what you get simply by doing a runtime suspend on some collection > > > of devices. I don't see that the kernel needs to treat it as a special > > > state, and in might be possible to have a user program manage the whole > > > thing -- provided the drivers in question implement runtime power > > > management (as USB has done). > > > > > > Alan Stern > > > > Except you always want early-suspend and auto-suspend at the same time. The > > idea is, if all display of system states is off (early-suspend), we can > > enable or disable the cpu at will (auto-suspend) because nobody will notice. > > Why should the kernel have to get involved? Why can't userspace manage > both early-suspend and auto-suspend? > > That is, consider the following: Userspace initiates an early-suspend > by using a runtime PM interface to turn off the screen and some other > devices. After a short time, if they are still off, then userspace can > initiate an auto-suspend by writing "auto-mem" to /sys/power/state. > > All the kernel would need to know is the difference between > auto-suspend and normal suspend: one respects wakelocks and the other > doesn't. It sounds to me like all of this stuff is just power management of individual devices, which should be done through the sysfs interface and completely unrelated to /sys/power/state. I'm putting the talk about suspending the CPU in this box too because it sounds like the desire is to stop the CPU without necessarily suspending other devices such as transmitters - sort of a CPU freq state where the frequency is 0. That said, if suspend to ram is what they really want for 'auto-mem', what you're suggesting sounds good to me. Regards, Nigel _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
