Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759124Ab3GaKS4 (ORCPT ); Wed, 31 Jul 2013 06:18:56 -0400 Received: from hydra.sisk.pl ([212.160.235.94]:48692 "EHLO hydra.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754181Ab3GaKSy (ORCPT ); Wed, 31 Jul 2013 06:18:54 -0400 From: "Rafael J. Wysocki" To: Aaron Lu Cc: ACPI Devel Maling List , LKML , Linux PM list , Yinghai Lu , Bjorn Helgaas , Tejun Heo , linux-ide@vger.kernel.org Subject: Re: [PATCH 1/3] ACPI / PM: Only set power states of devices that are power manageable Date: Wed, 31 Jul 2013 12:29:02 +0200 Message-ID: <5221650.Ris8idu00z@vostro.rjw.lan> User-Agent: KMail/4.9.5 (Linux/3.10.0+; KDE/4.9.5; x86_64; ; ) In-Reply-To: <51F8B35A.6000804@intel.com> References: <10433383.dueoNg39qi@vostro.rjw.lan> <1738639.5UcWLydKxR@vostro.rjw.lan> <51F8B35A.6000804@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3919 Lines: 98 On Wednesday, July 31, 2013 02:48:58 PM Aaron Lu wrote: > On 07/30/2013 10:04 PM, Rafael J. Wysocki wrote: > > On Tuesday, July 30, 2013 07:43:48 AM Aaron Lu wrote: > >> 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 > >>>>> > >>>>> 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? > > > > In fact, it doesn't need to check flags.power_manageable after this patch > > and the debug message won't be missed I think, so please just remove > > the whole if () from there, if that's not a problem. > > Patch to remove the redundant check, apply on top of this one. > > From: Aaron Lu > Subject: [PATCH 1/3] ACPI / PM: Remove redundant check for power manageable in > acpi_bus_set_power > > Now that we will check if a device is power manageable in > acpi_device_set_power, it is no longer necessary to do this check in > acpi_bus_set_power, so remove it. > > Signed-off-by: Aaron Lu Looks good, I'll queue it up for 3.12. Thanks, Rafael > --- > drivers/acpi/device_pm.c | 7 ------- > 1 file changed, 7 deletions(-) > > diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c > index 63324b8..8270711 100644 > --- a/drivers/acpi/device_pm.c > +++ b/drivers/acpi/device_pm.c > @@ -245,13 +245,6 @@ int acpi_bus_set_power(acpi_handle handle, int state) > if (result) > return result; > > - if (!device->flags.power_manageable) { > - ACPI_DEBUG_PRINT((ACPI_DB_INFO, > - "Device [%s] is not power manageable\n", > - dev_name(&device->dev))); > - return -ENODEV; > - } > - > return acpi_device_set_power(device, state); > } > EXPORT_SYMBOL(acpi_bus_set_power); > -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/