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From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Frank Hofmann <frank.hofmann@tomtom.com>
Cc: Dave Martin <dave.martin@linaro.org>,
	linux-pm@lists.linux-foundation.org,
	linux-arm-kernel@lists.infradead.org,
	tuxonice-devel@tuxonice.net
Subject: Re: [RFC PATCH] ARM hibernation / suspend-to-disk	support code
Date: Mon, 23 May 2011 15:32:17 +0100	[thread overview]
Message-ID: <20110523143216.GA14131@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <alpine.DEB.2.00.1105231239270.8018@localhost6.localdomain6>

On Mon, May 23, 2011 at 02:37:19PM +0100, Frank Hofmann wrote:
> What I've found necessary to save/restore via swsusp_arch_suspend/resume  
> are the SYSTEM_MODE and SVC_MODE registers.
> Yesterday, I had thought that cpu_init() resets SVC_MODE sufficiently but 
> that doesn't seem to be the case, if I leave that out, resume-from-disk  
> doesn't work anymore.

You will be running in SVC mode, so the SVC mode registers are your
current register set.  At some point you need to do an effective
"context switch" between the kernel doing the resume and the kernel
which was running.  That involves restoring the saved register state.

System mode on the other hand is unused by the kernel.

WARNING: multiple messages have this Message-ID (diff)
From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [linux-pm] [RFC PATCH] ARM hibernation / suspend-to-disk support code
Date: Mon, 23 May 2011 15:32:17 +0100	[thread overview]
Message-ID: <20110523143216.GA14131@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <alpine.DEB.2.00.1105231239270.8018@localhost6.localdomain6>

On Mon, May 23, 2011 at 02:37:19PM +0100, Frank Hofmann wrote:
> What I've found necessary to save/restore via swsusp_arch_suspend/resume  
> are the SYSTEM_MODE and SVC_MODE registers.
> Yesterday, I had thought that cpu_init() resets SVC_MODE sufficiently but 
> that doesn't seem to be the case, if I leave that out, resume-from-disk  
> doesn't work anymore.

You will be running in SVC mode, so the SVC mode registers are your
current register set.  At some point you need to do an effective
"context switch" between the kernel doing the resume and the kernel
which was running.  That involves restoring the saved register state.

System mode on the other hand is unused by the kernel.

  reply	other threads:[~2011-05-23 14:32 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <3DCE2F529B282E4B8F53D4D8AA406A07014FFE@008-AM1MPN1-022.mgdnok.nokia.com>
2011-05-19 17:31 ` [RFC PATCH] ARM hibernation / suspend-to-disk support code Frank Hofmann
2011-05-20 11:37   ` Dave Martin
2011-05-20 11:37   ` Dave Martin
2011-05-20 12:39     ` Frank Hofmann
2011-05-20 12:39       ` Frank Hofmann
2011-05-20 15:03       ` Dave Martin
2011-05-20 15:03       ` Dave Martin
2011-05-20 16:24         ` Frank Hofmann
2011-05-23  9:42           ` Dave Martin
2011-05-23  9:42           ` Dave Martin
2011-05-20 16:24         ` Frank Hofmann
2011-05-20 17:53         ` Nicolas Pitre
2011-05-20 17:53         ` Nicolas Pitre
2011-05-20 18:07       ` Russell King - ARM Linux
2011-05-20 18:07       ` Russell King - ARM Linux
2011-05-22  6:39         ` Frank Hofmann
2011-05-20 22:27       ` [linux-pm] " Rafael J. Wysocki
2011-05-22  7:01         ` Frank Hofmann
2011-05-22  9:54           ` Rafael J. Wysocki
2011-05-22  9:54           ` Rafael J. Wysocki
2011-05-22  7:01         ` Frank Hofmann
2011-05-23  9:52         ` Dave Martin
2011-05-23  9:52         ` [linux-pm] " Dave Martin
2011-05-23 13:37           ` Frank Hofmann
2011-05-23 14:32             ` Russell King - ARM Linux [this message]
2011-05-23 14:32               ` Russell King - ARM Linux
2011-05-23 15:57               ` [RFC PATCH v2] " Frank Hofmann
2011-05-23 15:57               ` Frank Hofmann
2011-05-23 13:37           ` [RFC PATCH] " Frank Hofmann
2011-05-20 22:27       ` Rafael J. Wysocki
2011-05-20 18:05     ` Russell King - ARM Linux
2011-05-20 18:05     ` Russell King - ARM Linux
2011-05-23 10:01       ` Dave Martin
2011-05-23 10:12         ` Russell King - ARM Linux
2011-05-23 10:12         ` Russell King - ARM Linux
2011-05-23 11:16           ` Dave Martin
2011-05-23 16:11             ` Russell King - ARM Linux
2011-05-23 16:38               ` Dave Martin
2011-05-24 12:33                 ` Frank Hofmann
2011-05-24 12:33                 ` Frank Hofmann
2011-05-23 16:38               ` Dave Martin
2011-05-23 16:11             ` Russell King - ARM Linux
2011-05-23 11:16           ` Dave Martin
2011-05-23 10:01       ` Dave Martin
2011-05-24 13:27     ` [RFC] ARM hibernation, cpu-type-specific code Frank Hofmann
2011-05-19 17:31 ` [RFC PATCH] ARM hibernation / suspend-to-disk support code Frank Hofmann

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