On Mon, Feb 7, 2022 at 10:04 AM Jan Stary <[email protected]> wrote: > On Feb 05 13:41:25, [email protected] wrote: > > On Sat, Feb 5, 2022 at 2:54 AM Jan Stary <[email protected]> wrote: > > > > > This is current/amd64 on a Thinkapd T420s, dmesgs below. > > > It seems that C2 is or is not supported depending on > > > whether the machine boots on AC or on battery > > > (judging by three boots of each). > > > Is this intended? > > > > The acpicpu driver is reporting what ACPI told it; presumably the authors > > of the AML intended this change as a way to reduce power consumption. > > > > Now, ACPI provides a mechanism for the OS to tell it to notify the OS if > > the contents of the _CST table changes and at least in some cases > > acpicpu registers for that and if called it would write new acpicpu lines > > to the dmesg. > > > > If you're not seeing those when plugging/unplugging, > > I don't. > > > there are two > > possibilities: > > * does the AML on your system actually change the values and trigger the > > notify? > > * is acpicpu actually registering the callback correctly? > > > > I would suggest adding a printf() right before the aml_register_notify() > > call in acpicpu.c to see if it's actually being hit, > > Probably not: I added a printf() right there > but nothing shows in dmesg when plugging/unpluging. >
That aml_register_notify() path is a *boot* time path, when acpicpu is attaching. What printf() did you add and did it appear during boot? If not, then the OS isn't registering the notify callback. Please send a report to bugs@ with sendbug as root, including the acpidump output. Philip Guenther
