I have been looking into the possibility of having the system automatically enter and exit S1 to save power when idle, but actively in use. For instance, while you are only browsing the web on your laptop, your eyes spend 15 seconds scanning the page while the system is otherwise, doing nothing but wait for your next input. It would be nice if it could seamlessly enter S1 during this time to save power, and exit when you press a key, move the mouse, or receive a message on IRC. Unlike S3, S1 keeps the Vcc power plane on and all devices remain in D0 or D1, so the screen remains on and visible, so it should be possible to use this state transparently without the user even being aware of it. Since everything remains on, no hardware needs reinitialized when resuming from S1. Here seems to be a problem with the current kernel code: It seems that the generic pm core code defined the PM_EVENT_SUSPEND state with S3 in mind, and so hardware drivers are notified of PM_EVENT_SUSPEND and reinitialized when resuming, assuming that the hardware lost power. When using acpi S1, this reinitialization activity is not required and should not be done, so it seems that S1 should not generate PM_EVENT_SUSPEND and PM_EVENT_RESUME events. Does anyone have any thoughts on my conclusion or advice on how to trigger S1 without generating PM_EVENT_SUSPEND? -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
