Return-path: Received: from mga02.intel.com ([134.134.136.20]) by bombadil.infradead.org with esmtp (Exim 4.68 #1 (Red Hat Linux)) id 1IukWw-0003rG-K7 for kexec@lists.infradead.org; Wed, 21 Nov 2007 03:02:01 -0500 Subject: Re: [PATCH 3/3 -mm] kexec based hibernation -v6: kexec hibernate/resume From: "Huang, Ying" In-Reply-To: <200711210100.32631.rjw@sisk.pl> References: <1195455769.10291.26.camel@caritas-dev.intel.com> <200711200324.31180.rjw@sisk.pl> <1195527033.11955.50.camel@caritas-dev.intel.com> <200711210100.32631.rjw@sisk.pl> Date: Wed, 21 Nov 2007 16:05:06 +0800 Message-Id: <1195632306.29280.7.camel@caritas-dev.intel.com> Mime-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: kexec-bounces@lists.infradead.org Errors-To: kexec-bounces+dwmw2=infradead.org+dwmw2=infradead.org@lists.infradead.org To: "Rafael J. Wysocki" Cc: nigel@nigel.suspend2.net, Kexec Mailing List , linux-kernel@vger.kernel.org, "Eric W. Biederman" , Pavel Machek , Andrew Morton , linux-pm@lists.linux-foundation.org, Jeremy Maitin-Shepard On Wed, 2007-11-21 at 01:00 +0100, Rafael J. Wysocki wrote: > On Tuesday, 20 of November 2007, Huang, Ying wrote: > > On Tue, 2007-11-20 at 03:24 +0100, Rafael J. Wysocki wrote: > > > On Tuesday, 20 of November 2007, Huang, Ying wrote: > > > > On Mon, 2007-11-19 at 19:22 +0100, Rafael J. Wysocki wrote: > > > > > > +#ifdef CONFIG_KEXEC > > > > > > +static void kexec_hibernate_power_down(void) > > > > > > +{ > > > > > > + switch (hibernation_mode) { > > > > > > + case HIBERNATION_TEST: > > > > > > + case HIBERNATION_TESTPROC: > > > > > > + break; > > > > > > + case HIBERNATION_REBOOT: > > > > > > + machine_restart(NULL); > > > > > > + break; > > > > > > + case HIBERNATION_PLATFORM: > > > > > > + if (!hibernation_ops) > > > > > > + break; > > > > > > + hibernation_ops->enter(); > > > > > > > > > > hibernation_platform_enter() should be used here (as of the current mainline). > > > > > > > > The power_down will be called with interrupt disabled, device suspended, > > > > non-boot CPU disabled. But the latest hibernate_platform_enter calls the > > > > device_suspend, disable_nonboot_cpus etc function. So, I use > > > > hibernation_ops->enter() directly instead of > > > > hibernation_platform_enter(). > > > > > > Hm, you need to call device_power_down(PMSG_SUSPEND) before > > > hibernation_ops->enter(). > > > > > > Also, all of the ACPI global calls need to be carried out before that and the > > > devices should be suspended rather than shut down in that case. > > > > > > That's why hibernation_platform_enter() has been introduced, BTW. > > > > Situation is a little different between u/swsusp and khiberantion. > > > > u/swsusp: > > > > platform_start(); > > suspend console(); > > device_suspend(PMSG_FREEZE); > > platform_pre_snapshot(); > > disable_nonboot_cpus(); > > local_irq_disable(); > > device_power_down(PMSG_FREEZE); > > /* create snapshot */ > > device_power_up(); > > local_irq_enable(); > > enable_nonboot_cpus(); > > platform_finish(); > > device_resume(); > > resume_console(); > > /* write the image out */ > > hibernation_ops->start(); > > suspend_console(); > > device_suspend(PMSG_SUSPEND); > > hibernation_ops->prepare(); > > disable_nonboot_cpus(); > > local_irq_disable(); > > device_power_down(PMSG_SUSPEND); > > hibernation_ops->enter(); > > > > khibernation: > > > > suspend_console(); > > platform_start(); > > device_suspend(PMSG_FREEZE); > > platform_pre_snapshot(); > > disable_nonboot_cpus(); > > local_irq_disable(); > > device_power_down(PMSG_FREEZE); > > /* jump to kexeced (hibernating) kernel */ > > /* in kexeced kernel */ > > device_power_up(); > > local_irq_eanble(); > > enable_nonboot_cpus(); > > You should call platform_finish() here, or device_resume() will not work > appropriately on some systems. > > However, after platform_finish() has been executed, the ACPI firmware will > assume that the hibernation has been canceled, so you need to tell it that > you'd like to go into the low power state after all. > > > device_resume(); > > resume_console(); > > /* write the image */ > > For this reason, you have to call hibernation_ops->start() once again > and the other functions like in the swsusp case, in that order. > > > suspend_console(); > > device_suspend(PMSG_FREEZE); > > disable_nonboot_cpus(); > > local_irq_disable(); > > device_power_down(PMSG_FREEZE); > > /* jump to original (hibernated) kernel */ > > This looks too fragile to my eyes. > > Why don't you call hibernation_ops->enter() directly from the "kexeced" kernel? I don't know whether there are ACPI global state inside Linux kernel. So I restrict all ACPI method calling in original kernel. If the ACPI global state in Linux kernel is not a issue, I can call hibernation_ops->enter() directly in the "kexeced" kernel. Best Regards, Huang Ying _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec