From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Dexuan Cui <decui@microsoft.com>
Cc: Michael Kelley <mikelley@microsoft.com>,
"linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
"rjw@rjwysocki.net" <rjw@rjwysocki.net>,
"lenb@kernel.org" <lenb@kernel.org>,
"robert.moore@intel.com" <robert.moore@intel.com>,
"erik.schmauss@intel.com" <erik.schmauss@intel.com>,
Russ Dill <Russ.Dill@ti.com>,
Sebastian Capella <sebastian.capella@linaro.org>,
Pavel Machek <pavel@ucw.cz>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
KY Srinivasan <kys@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Sasha Levin <Alexander.Levin@microsoft.com>,
"olaf@aepfle.de" <olaf@aepfle.de>,
"apw@canonical.com" <apw@canonical.com>,
"jasowang@redhat.com" <jasowang@redhat.com>,
vkuznets <vkuznets@redhat.com>,
"marcelo.cerri@canonical.com" <marcelo.cerri@canonical.com>
Subject: Re: [PATCH] ACPI: PM: Export the function acpi_sleep_state_supported()
Date: Fri, 14 Jun 2019 23:33:10 +0100 [thread overview]
Message-ID: <20190614223310.pwwoefu5qdvcuaiy@shell.armlinux.org.uk> (raw)
In-Reply-To: <PU1P153MB01699020B5BC4287C58F5335BFEE0@PU1P153MB0169.APCP153.PROD.OUTLOOK.COM>
Hi,
On Fri, Jun 14, 2019 at 10:19:02PM +0000, Dexuan Cui wrote:
> > -----Original Message-----
> > From: Michael Kelley <mikelley@microsoft.com>
> > Sent: Friday, June 14, 2019 1:48 PM
> > To: Dexuan Cui <decui@microsoft.com>; linux-acpi@vger.kernel.org;
> > rjw@rjwysocki.net; lenb@kernel.org; robert.moore@intel.com;
> > erik.schmauss@intel.com
> > Cc: linux-hyperv@vger.kernel.org; linux-kernel@vger.kernel.org; KY Srinivasan
> > <kys@microsoft.com>; Stephen Hemminger <sthemmin@microsoft.com>;
> > Haiyang Zhang <haiyangz@microsoft.com>; Sasha Levin
> > <Alexander.Levin@microsoft.com>; olaf@aepfle.de; apw@canonical.com;
> > jasowang@redhat.com; vkuznets <vkuznets@redhat.com>;
> > marcelo.cerri@canonical.com
> > Subject: RE: [PATCH] ACPI: PM: Export the function
> > acpi_sleep_state_supported()
> >
> > It seems that sleep.c isn't built when on the ARM64 architecture. Using
> > acpi_sleep_state_supported() directly in hv_balloon.c will be problematic
> > since hv_balloon.c needs to be architecture independent when the
> > Hyper-V ARM64 support is added. If that doesn't change, a per-architecture
> > wrapper will be needed to give hv_balloon.c the correct information. This
> > may affect whether acpi_sleep_state_supported() needs to be exported vs.
> > just removing the "static". I'm not sure what the best approach is.
> >
> > Michael
>
> + some ARM experts who worked on arch/arm/kernel/hibernate.c.
>
> drivers/acpi/sleep.c is only built if ACPI_SYSTEM_POWER_STATES_SUPPORT
> is defined, but it looks this option is not defined on ARM.
>
> It looks ARM does not support the ACPI S4 state, then how do we know
> if an ARM host supports hibernation or not?
Don't forget that Linux does not support ACPI on 32-bit ARM, which is
quite different from the situation on 64-bit ARM.
arch/arm/kernel/hibernate.c is only for 32-bit ARM, and is written with
the assumption that there is no interaction required with any firmware
to save state, and later restore state upon resuming.
Or am I missing something?
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
According to speedtest.net: 11.9Mbps down 500kbps up
next prev parent reply other threads:[~2019-06-14 22:33 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-14 18:19 [PATCH] ACPI: PM: Export the function acpi_sleep_state_supported() Dexuan Cui
2019-06-14 20:48 ` Michael Kelley
2019-06-14 22:19 ` Dexuan Cui
2019-06-14 22:33 ` Russell King - ARM Linux admin [this message]
2019-06-14 23:34 ` Dexuan Cui
2019-06-17 13:08 ` Pavel Machek
2019-06-17 13:09 ` Pavel Machek
2019-06-17 16:14 ` Lorenzo Pieralisi
2019-06-19 19:54 ` Dexuan Cui
2019-06-20 11:30 ` Pavel Machek
2019-06-21 7:15 ` Dexuan Cui
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