From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [linux-pm] [PATCH 46/76] ACPI: Introduce ACPI D3_COLD state support Date: Sun, 1 Apr 2012 08:53:33 +0200 Message-ID: <201204010853.33667.rjw@sisk.pl> References: <1333102459-23750-1-git-send-email-lenb@kernel.org> <3ebc81b8937d2bc1d0d0064bed29434dfce490aa.1333101989.git.len.brown@intel.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from ogre.sisk.pl ([217.79.144.158]:47549 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750903Ab2DAGtN (ORCPT ); Sun, 1 Apr 2012 02:49:13 -0400 In-Reply-To: <3ebc81b8937d2bc1d0d0064bed29434dfce490aa.1333101989.git.len.brown@intel.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: linux-pm@lists.linux-foundation.org, Len Brown , Lin Ming Cc: linux-acpi@vger.kernel.org, Len Brown , linux-kernel@vger.kernel.org, Linux PM mailing list On Friday, March 30, 2012, Len Brown wrote: > From: Zhang Rui > > If a device has _PR3, it means the device supports D3_COLD. > Add the ability to validate and enter D3_COLD state in ACPI. This patch is wrong, IMO. Namely, _PR3 lists power resources that are supposed to be "on" in D3, which means that in that state the device is not completely off, so this must be D3_hot and not D3_cold. So. _PR3 means D3_hot is supported. D3_cold, on the other hand, is always supported, although it may not be accessible through any direct software action (for example, it may be necessary to power down a bus to put devices on it into D3_cold). Thanks, Rafael > Signed-off-by: Zhang Rui > Signed-off-by: Lin Ming > Signed-off-by: Len Brown > --- > drivers/acpi/power.c | 4 ++-- > drivers/acpi/scan.c | 7 +++++++ > 2 files changed, 9 insertions(+), 2 deletions(-) > > diff --git a/drivers/acpi/power.c b/drivers/acpi/power.c > index 9ac2a9f..0d681fb 100644 > --- a/drivers/acpi/power.c > +++ b/drivers/acpi/power.c > @@ -500,14 +500,14 @@ int acpi_power_transition(struct acpi_device *device, int state) > { > int result; > > - if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3)) > + if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD)) > return -EINVAL; > > if (device->power.state == state) > return 0; > > if ((device->power.state < ACPI_STATE_D0) > - || (device->power.state > ACPI_STATE_D3)) > + || (device->power.state > ACPI_STATE_D3_COLD)) > return -ENODEV; > > /* TBD: Resources must be ordered. */ > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c > index 8ab80ba..571396c 100644 > --- a/drivers/acpi/scan.c > +++ b/drivers/acpi/scan.c > @@ -885,6 +885,13 @@ static int acpi_bus_get_power_flags(struct acpi_device *device) > acpi_bus_add_power_resource(ps->resources.handles[j]); > } > > + /* The exist of _PR3 indicates D3Cold support */ > + if (i == ACPI_STATE_D3) { > + status = acpi_get_handle(device->handle, object_name, &handle); > + if (ACPI_SUCCESS(status)) > + device->power.states[ACPI_STATE_D3_COLD].flags.valid = 1; > + } > + > /* Evaluate "_PSx" to see if we can do explicit sets */ > object_name[2] = 'S'; > status = acpi_get_handle(device->handle, object_name, &handle); >