On Thu, 2012-09-20 at 00:38 -0700, Eric W. Biederman wrote: > Bjorn Helgaas <bhelgaas at google.com> writes: > > > +cc Eric and kexec list > > > > On Mon, Sep 17, 2012 at 2:54 AM, Huang Ying <ying.huang at intel.com> 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. > > 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. Best Regards, Huang Ying > >> Signed-off-by: Huang Ying <ying.huang at intel.com> > >> --- > >> 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 at lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/kexec
