Talk:Hardware Power Domains

Power Domain Discussion

No support for optional ACPI Sleep state S2

• S2 is uninteresting. IMHO - its a vague state literally defined as "higher latency then S1 but lower latency then S3". Not sure if your itention here is to mention that S2 *should*

be supported, or just commenting that it isn't. - JordanCrouse (Talk to me!) 18:58, 12 September 2006 (EDT)

C1 Test

This confused me for a second - what you're talking about is really more of a poor man's S1 - turning off pratically everything we can, turn off the PIT, and then enable wakeup devices and go to a hlt. A more correct name might be low-latency S1, because it will be slower then a C state transition (obivously) but it should be faster then a S1 transition.

This is quite similar to a tickless system, except that we turn off more devices. The only question is - how quickly can we turn off and turn on the un-needed devices, and does that latency fit within the average idle timesice of a nominally busy kernel? I believe that we can measure the average length between timeouts in the kernel with Systemtap - that would be useful information to have. If we can make this all fit - it would be a heck of a cool thing. - JordanCrouse (Talk to me!) 19:16, 12 September 2006 (EDT)

Another question - keeping in mind that we can't lose context in this mode - what devices would we possibly shut off that would have an effect on the total power consumption during C1? - JordanCrouse (Talk to me!) 19:40, 12 September 2006 (EDT)