On Mon, 2012-11-26 at 11:21 -0500, Alan Stern wrote: > On Mon, 26 Nov 2012, James Bottomley wrote: > > > I'm also curious about driving sleep from autopm, since mode page timers > > don't control the sleep transition. > > Is it feasible to do this the other way around? That is, to drive > runtime suspend by noticing when the device decides to put itself into > a low-power state? Well, yes and no. The spec is annoyingly (and deliberately) vague about what the states actually mean. The two states that the devices go into because of timers is idle and standby. The supposedly deeper low power state of sleep can only be reached by sending a command to the device. The design is that software (or HBA drivers) don't really need to notice idle and standby; the device automatically manages transitions between them depending on command activity. For sleep, we do have to care (if it actually makes some meaningful difference). James -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
