On Monday, September 10, 2012, Aaron Lu wrote: > On Fri, Sep 07, 2012 at 08:32:55PM +0200, Rafael J. Wysocki wrote: > > On Friday, September 07, 2012, Aaron Lu wrote: > > > On 09/07/2012 07:46 PM, Rafael J. Wysocki wrote: > > > >> Yes, on a test system, when I try to put a device into D3 cold and ACPI > > > >> will complain that I can't due to its parent is in a even lower power > > > >> state UNKNOWN(255), this parent device is power manageable but has no > > > >> _PSC and _PRx defined. > > > > > > > > Perhaps we can force _PS0 for such devices to start with, so that we know > > > > for sure that the initial state is D0? > > > > > > Sounds good, I'll update the patch, thanks for the advice. > > > > Actually, I suppose we can do something like the appended patch instead. > > > > I wonder if it works around the particular problem you're seeing? > > Yes, thanks. > > Reviewed-by: Aaron Lu <aaron.lu@xxxxxxxxx> Cool, thanks for testing! I'll resend it shortly with a proper changelog. Thanks, Rafael > > --- > > drivers/acpi/bus.c | 11 ++++++++++- > > 1 file changed, 10 insertions(+), 1 deletion(-) > > > > Index: linux/drivers/acpi/bus.c > > =================================================================== > > --- linux.orig/drivers/acpi/bus.c > > +++ linux/drivers/acpi/bus.c > > @@ -229,7 +229,16 @@ static int __acpi_bus_get_power(struct a > > result = psc; > > } > > /* The test below covers ACPI_STATE_UNKNOWN too. */ > > - if (result <= ACPI_STATE_D2) { > > + if (result == ACPI_STATE_D0) { > > + /* > > + * If we were unsure about the device parent's power state up to > > + * this point, the fact that the device is in D0 implies that > > + * the parent has to be in D0 too. > > + */ > > + if (device->parent > > + && device->parent->power.state == ACPI_STATE_UNKNOWN) > > + device->parent->power.state = ACPI_STATE_D0; > > + } else if (result <= ACPI_STATE_D2) { > > ; /* Do nothing. */ > > } else if (device->power.flags.power_resources) { > > int error = acpi_power_get_inferred_state(device, &result); > > -- 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