From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zhang Rui Subject: Re: [RFC PATCH 1/6] ACPI: Introduce ACPI D3_COLD state support Date: Tue, 14 Feb 2012 15:07:08 +0800 Message-ID: <1329203228.19384.35.camel@rui.sh.intel.com> References: <1329124271-29464-1-git-send-email-ming.m.lin@intel.com> <1329124271-29464-2-git-send-email-ming.m.lin@intel.com> <201202132125.15537.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <201202132125.15537.rjw@sisk.pl> Sender: linux-acpi-owner@vger.kernel.org To: "Rafael J. Wysocki" Cc: Lin Ming , Jeff Garzik , Alan Stern , Tejun Heo , Len Brown , linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org, linux-pm@vger.kernel.org, ACPI Devel Mailing List List-Id: linux-scsi@vger.kernel.org Hi, Rafael, On =E4=B8=80, 2012-02-13 at 21:25 +0100, Rafael J. Wysocki wrote: > On Monday, February 13, 2012, Lin Ming wrote: > > From: Zhang Rui > >=20 > > If a device has _PR3._ON, it means the device supports D3_HOT. > > If a device has _PR3._OFF, it means the device supports D3_COLD. > > Add the ability to validate and enter D3_COLD state in ACPI. > >=20 > > Signed-off-by: Zhang Rui >=20 > This is supposed to be ACPI 5.0 support, right? >=20 No, D3_HOT is introduced in ACPI spec 4.0. According to the spec, _PR3 is used for devices that support both D3(D3_COLD) and D3HOT. The confusion here is that Linux D3 equals ACPICA D3HOT and Linux D3_COLD equals ACPICA D3. =46or example, when enter Linux ACPI D3, the reference count of ACPI Po= wer Resources in _PR3 is increased by one. > So can anyone please tell me what part of the ACPI 5.0 spec is the > basis of this patch, because I can't see that immediately? >=20 > The only places where D3Cold is _mentioned_ are Section 7.2.12 (_PRE,= which > appears to be new in 5.0), Section 7.2.20 (_S0W), Section 7.2.21 (_S1= W), > Section 7.2.22 (_S2W), Section 7.2.23 (_S3W) and Section 7.2.24 (_S4W= ). > None of them mentions those _PR3._ON and _PR3._OFF things above. >=20 > Moreover, my understanding of the spec is that D3Cold means all of th= e > power resources returned by _PR3 are "off" (whereas some of them will= be > "on" in D3hot). >=20 Agreed. > > --- > > drivers/acpi/power.c | 4 ++-- > > drivers/acpi/scan.c | 10 +++++++++- > > 2 files changed, 11 insertions(+), 3 deletions(-) > >=20 > > 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; > > =20 > > - if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3)= ) > > + if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_= COLD)) > > return -EINVAL; > > =20 > > if (device->power.state =3D=3D state) > > return 0; > > =20 > > if ((device->power.state < ACPI_STATE_D0) > > - || (device->power.state > ACPI_STATE_D3)) > > + || (device->power.state > ACPI_STATE_D3_COLD)) > > return -ENODEV; > > =20 > > /* TBD: Resources must be ordered. */ > > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c > > index 8ab80ba..a9d4391 100644 > > --- a/drivers/acpi/scan.c > > +++ b/drivers/acpi/scan.c > > @@ -881,8 +881,16 @@ static int acpi_bus_get_power_flags(struct acp= i_device *device) > > =20 > > device->power.flags.power_resources =3D 1; > > ps->flags.valid =3D 1; > > - for (j =3D 0; j < ps->resources.count; j++) > > + for (j =3D 0; j < ps->resources.count; j++) { > > acpi_bus_add_power_resource(ps->resources.handles[j]); > > + /* Check for D3_COLD support. _PR3._OFF equals D3_COLD ? */ > > + if (i =3D=3D ACPI_STATE_D3) { > > + if (j =3D=3D 0) > > + device->power.states[ACPI_STATE_D3_COLD].flags.valid =3D 1; > > + status =3D acpi_get_handle(ps->resources.handles[j], "_OFF", = &handle); > > + device->power.states[ACPI_STATE_D3_COLD].flags.valid &=3D ACP= I_SUCCESS(status); > > + } > > + } >=20 > Sorry, but this doesn't make sense to me. Power resources always hav= e > the _OFF method, right? >=20 I'm not sure. I thought I had seen ACPI Power Resources without _OFF control method somewhere in bugzilla, but I can not find it out now. Hmm, how about set D3_COLD support if _PR3 exists, but leave a warning message if _OFF doesn't exist, for now? thanks, rui -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html