On Wed, Dec 09, 2009 at 12:10:03PM -0500, Alan Stern wrote: > On Wed, 9 Dec 2009, Mark Brown wrote: > > Worst case is about a second for both resume and suspend which means two > > seconds total but it's very hardware dependant. > A second seems awfully long. What happens if audio isn't being played > when the suspend occurs? Can't you shorten things with no artifacts in > that case? For the affected hardware the problem is basically the same with or without audio being played. As I said in my reply to Linus this is delays caused by ramping reference voltages. These delays are sufficiently long that the reference voltages have to be maintained all the time so that they don't delay the start of audio streams which means that having or not having an audio stream at suspend time doesn't affect the reference voltage ramps since we don't turn them off when not in use. There is a win from other stuff having been shut off already, but it's already being exploited. On suspend the problem is the same as for resume - we need to ramp the voltages quietly, this time down to zero. We want to make sure they're actually at zero to ensure that the ramp at resume time starts from a known hardware state. -- 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
