On Thu, 2014-10-23 at 18:00 +0200, Andreas Hartmann wrote: > Alex Williamson wrote: > > On Wed, 2014-10-22 at 18:22 +0200, Andreas Hartmann wrote: > >> Alex Williamson wrote: > >>> --- a/drivers/pci/pci.c > >>> +++ b/drivers/pci/pci.c > >>> @@ -3308,15 +3308,15 @@ static int __pci_dev_reset(struct pci_dev *dev, int prob > >>> if (rc != -ENOTTY) > >>> goto done; > >>> > >>> - rc = pci_pm_reset(dev, probe); > >>> + rc = pci_dev_reset_slot_function(dev, probe); > >>> if (rc != -ENOTTY) > >>> goto done; > >>> > >>> - rc = pci_dev_reset_slot_function(dev, probe); > >>> + rc = pci_parent_bus_reset(dev, probe); > >>> if (rc != -ENOTTY) > >>> goto done; > >>> > >>> - rc = pci_parent_bus_reset(dev, probe); > >>> + rc = pci_pm_reset(dev, probe); > >>> done: > >>> return rc; > >>> } > >> > >> This way it's crashing with echo 1 > reset, too. > > > > Ok, so it's somehow related to doing a bus reset with virtual channel > > save/restore while PM reset with VC save/restore works ok as apparently > > does bus reset without VC save/restore. Let's try to do a manual bus > > reset so we can look at the post reset state of the device before the > > kernel tries to restore it. > > > > First bind the target device 03:00.0 to pci-stub or vfio-pci so that we > > know it's not being used. > > > > Next capture lspci -xxxx -s 3:00.0 so we have the starting state. > > > > Then we'll do a bus reset using setpci: > > # setpci -s 00:05.0 3e.w=40:40 > > <if you script this, wait at least 2ms here> > > # setpci -s 00:05.0 3e.w=00:40 > > <wait 1 second here> > > > > Now re-capture lspci -xxxx -s 3:00.0 > > The machine is booted w/ vfio bound to 3:00.0 as usual (now for testing > linux 3.14) > > lspci -xxxx -s 3:00.0 > setpci -s 00:05.0 3e.w=40:40 > usleep 10 > setpci -s 00:05.0 3e.w=00:40 > sleep 1 > lspci -xxxx -s 3:00.0 > > I didn't get the second lspci because the machine already was hanging. > The first output is attached completely. Hmm, that doesn't make much sense. You had found that if you disabled the VC save/restore then QEMU works. That should have still been using secondary bus reset as we're trying to do here, so I don't understand why we can't do a manual secondary bus reset now. If you use Bjorn's previous patch to disable VC save/restore and my patch to reorder the reset mechanisms, does echo 1 > reset for the sysfs entry for the device also still cause a hang? Can you provide a link to the specific model for this card? Thanks, Alex -- 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
