From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753036Ab2ITI1o (ORCPT ); Thu, 20 Sep 2012 04:27:44 -0400 Received: from out03.mta.xmission.com ([166.70.13.233]:38577 "EHLO out03.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751818Ab2ITI1k (ORCPT ); Thu, 20 Sep 2012 04:27:40 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Huang Ying Cc: Bjorn Helgaas , linux-pm@vger.kernel.org, linux-pci@vger.kernel.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, "Rafael J. Wysocki" References: <1347872076-5260-1-git-send-email-ying.huang@intel.com> <1347872076-5260-2-git-send-email-ying.huang@intel.com> <877grpywhy.fsf@xmission.com> <1348129173.8212.218.camel@yhuang-dev> Date: Thu, 20 Sep 2012 01:27:33 -0700 In-Reply-To: <1348129173.8212.218.camel@yhuang-dev> (Huang Ying's message of "Thu, 20 Sep 2012 16:19:33 +0800") Message-ID: <87fw6dxfnu.fsf@xmission.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=;;;mid=;;;hst=in02.mta.xmission.com;;;ip=98.207.153.68;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX19Jw9YLj0s5pLBg2fTFVjaOGL5iViMxTRQ= X-SA-Exim-Connect-IP: 98.207.153.68 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * 7.0 XM_URI_RBL URI blacklisted in uri.bl.xmission.com * [URIs: infradead.org] * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 1.5 XMNoVowels Alpha-numberic number with no vowels * 0.1 XMSubLong Long Subject * 0.0 T_TM2_M_HEADER_IN_MSG BODY: T_TM2_M_HEADER_IN_MSG * -3.0 BAYES_00 BODY: Bayes spam probability is 0 to 1% * [score: 0.0000] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa06 1397; Body=1 Fuz1=1 Fuz2=1] * 0.0 T_XMDrugObfuBody_08 obfuscated drug references X-Spam-DCC: XMission; sa06 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ****;Huang Ying X-Spam-Relay-Country: Subject: Re: [RFC 1/3] PCI/PM: Fix kexec for D3cold and bridge suspending X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Fri, 06 Aug 2010 16:31:04 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Huang Ying writes: > On Thu, 2012-09-20 at 00:38 -0700, Eric W. Biederman wrote: >> Bjorn Helgaas writes: >> >> > +cc Eric and kexec list >> > >> > On Mon, Sep 17, 2012 at 2:54 AM, Huang Ying wrote: >> >> If PCI devices are put into D3cold before kexec, because the >> >> configuration registers of PCI devices in D3cold are not accessible. >> >> >> >> And if PCI bridges are put into low power state before kexec, >> >> configuration registers of PCI devices underneath the PCI bridges are >> >> not accessible too. >> >> >> >> These will make some PCI devices can not be scanned after kexec, so >> >> resume the PCI devices in D3cold or PCI bridges in low power state >> >> before kexec. >> > >> > Don't we need to resume the device even without the kexec issue? And >> > even if it's in D1 or D2? >> >> The basic requirement is that the device needs to be visible so we can >> auto discover it. As I recall most sleep states don't make the device >> invisible and we can handle the rest in the device initializatoin code. > > PCI devices in D3cold or under a bridge in D3hot will not be visible, so > we must fix that for kexec to run properly. That seems reasonable to me. >> > It looks to me like pci_msi_shutdown() (and probably drv->shutdown()) >> > depend on the device being in D0. >> >> There is certainly a depenency on the config registers being visible. >> Although I don't know if much will go wrong if they aren't. >> >> Ceratinly pci_msi_shutdown doesn't have anything to do if the device has >> had so much power removed that the device is not even exectuing. > > Don't know which power state device should be in for pci_msi_shutdown > etc. But it appears that normal shutdown/reboot and kexec works at most > times so far. D3cold and bridge in D3hot works for normal > shutdown/reboot, but not for kexec. So I write some fix. To be clear. Has someone picked up this patch yet? Acked-by: "Eric W. Biederman" As for reboot it tends to always work because frequently the firmware code triggers a soft reset of the entire machine, which puts devices in their power on reset state, which is not a suspended state. Although that behavior is not required for a software reboot. Eric > Best Regards, > Huang Ying > >> >> Signed-off-by: Huang Ying >> >> --- >> >> drivers/pci/pci-driver.c | 4 ++++ >> >> 1 file changed, 4 insertions(+) >> >> >> >> --- a/drivers/pci/pci-driver.c >> >> +++ b/drivers/pci/pci-driver.c >> >> @@ -421,6 +421,10 @@ static void pci_device_shutdown(struct d >> >> struct pci_dev *pci_dev = to_pci_dev(dev); >> >> struct pci_driver *drv = pci_dev->driver; >> >> >> >> + /* Resume bridges and devices in D3cold for kexec to work properly */ >> >> + if (pci_dev->current_state == PCI_D3cold || pci_dev->subordinate) >> >> + pm_runtime_resume(dev); >> >> + >> >> if (drv && drv->shutdown) >> >> drv->shutdown(pci_dev); >> >> pci_msi_shutdown(pci_dev); >> > >> > _______________________________________________ >> > kexec mailing list >> > kexec@lists.infradead.org >> > http://lists.infradead.org/mailman/listinfo/kexec