Huang Ying <ying.huang@xxxxxxxxx> writes: > On Thu, 2012-09-20 at 00:38 -0700, Eric W. Biederman wrote: >> Bjorn Helgaas <bhelgaas@xxxxxxxxxx> writes: >> >> > +cc Eric and kexec list >> > >> > On Mon, Sep 17, 2012 at 2:54 AM, Huang Ying <ying.huang@xxxxxxxxx> 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" <ebiederm@xxxxxxxxxxxx> 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 <ying.huang@xxxxxxxxx> >> >> --- >> >> 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@xxxxxxxxxxxxxxxxxxx >> > http://lists.infradead.org/mailman/listinfo/kexec -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
