From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from out01.mta.xmission.com ([166.70.13.231]) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TEbLV-0005ut-Hn for kexec@lists.infradead.org; Thu, 20 Sep 2012 07:38:51 +0000 From: ebiederm@xmission.com (Eric W. Biederman) References: <1347872076-5260-1-git-send-email-ying.huang@intel.com> <1347872076-5260-2-git-send-email-ying.huang@intel.com> Date: Thu, 20 Sep 2012 00:38:33 -0700 In-Reply-To: (Bjorn Helgaas's message of "Mon, 17 Sep 2012 14:54:16 -0600") Message-ID: <877grpywhy.fsf@xmission.com> MIME-Version: 1.0 Subject: Re: [RFC 1/3] PCI/PM: Fix kexec for D3cold and bridge suspending 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@lists.infradead.org To: Bjorn Helgaas Cc: linux-pm@vger.kernel.org, linux-pci@vger.kernel.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, "Rafael J. Wysocki" , Huang Ying 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. > 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. Eric >> 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 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec