On 07/30/2013 06:21 AM, Rafael J. Wysocki wrote: > On Monday, July 29, 2013 10:09:53 PM Aaron Lu wrote: >> On 07/27/2013 09:10 PM, Rafael J. Wysocki wrote: >>> From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> >>> >>> Make acpi_device_set_power() check if the given device is power >>> manageable before checking if the given power state is valid for that >>> device. Otherwise it will print that "Device does not support" that >>> power state into the kernel log, which may not make sense for some >>> power states (D0 and D3cold are supported by all devices by >>> definition). >> >> It will not print "Device does not support" that power state if that >> power state is D0 or D3cold since we have unconditionally set those two >> power state's valid flag. > > So you didn't actually looked at acpi_bus_get_power_flags() that set the > power.states[].flags.valid flag, because If you had looked at it, you would > have seen that that's not the case. > > No, we don't set the valid flag for devices that aren't power manageable > (i.e. have flags.power_manageable unset), which is the *whole* *point* of > this change. Right, I missed this. Sorry for the noise. > >> OTOH, what value should we return for a device node that is not power >> manageable in acpi_device_set_power when the target state is D0 or D3 >> cold? The old behavior is to return 0, meanning success without taking >> any actual action. >> >> In acpi_bus_set_power, if the device is not power manageable, we will >> return -ENODEV; in acpi_dev_pm_full/low_power, we will return 0 as in >> the original acpi_device_set_power. So return -EINVAL here is correct? > > No, the original acpi_device_set_power() will return -ENODEV then, but > in my opinion returning -EINVAL is more accurate, because "power > manageable" means "you can change power state of it". Shall I prepare a patch to update the errno in acpi_bus_set_power? Thanks, Aaron > > Thanks, > Rafael > > >>> Tested-by: Yinghai Lu <yinghai@xxxxxxxxxx> >>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> >>> --- >>> drivers/acpi/device_pm.c | 3 ++- >>> 1 file changed, 2 insertions(+), 1 deletion(-) >>> >>> Index: linux-pm/drivers/acpi/device_pm.c >>> =================================================================== >>> --- linux-pm.orig/drivers/acpi/device_pm.c >>> +++ linux-pm/drivers/acpi/device_pm.c >>> @@ -159,7 +159,8 @@ int acpi_device_set_power(struct acpi_de >>> int result = 0; >>> bool cut_power = false; >>> >>> - if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD)) >>> + if (!device || !device->flags.power_manageable >>> + || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD)) >>> return -EINVAL; >>> >>> /* Make sure this is a valid target state */ >>> >> -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
