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. > 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 <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
