On Tuesday, 25 of December 2007, Rafael J. Wysocki wrote: > On Tuesday, 25 of December 2007, Carlos Corbacho wrote: > > Adding Linux-ACPI to CC. > > > > On Tuesday 25 December 2007 00:03:25 Carlos Corbacho wrote: > > > According to the earlier versions of the ACPI spec, Linux is doing the > > > wrong thing - we should call _PTS() before we start powerding down devices, > > > or notifying device drivers to start suspending. > > > > > > So, my limited understanding of what we currently do for ACPI > > > suspend-to-RAM is: > > > > > > 1) Freeze processes/ devices > > > 2) Put all devices into low power mode > > > 3) Execute _PTS() > > > 4) Suspend system > > > > > > So the problem is - our current suspend order is fine for ACPI 3.0 and > > > above, but for pre-3.0 systems, this violates the older specs, where 2) and > > > 3) should be reversed. > > > > The following is a hack to illustrate what I'm getting at (this is > > tested on x86-64) (it's a hack since it does all the ACPI prepare bits > > during set_target() for the pre ACPI 3.0 systems, rather than prepare() - > > whether this can be cleaned up to move out just the _PTS() call, I don't > > know). > > > > It abuses suspend_ops->set_target(), but was the easiest way to quickly > > demonstrate this (since the kerneldoc for set_target() says it will always > > be executed before we suspend the devices). > > Please, don't do that. OK, sorry, the approach is generally reasonable, IMO, but it needs to be a bit more fine grained. I'll try to prepare some patches along these lines soon. Thanks, Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
