OK, a couple more tweaks to the changelog.
On Fri, Apr 10, 2015 at 05:54:47PM -0500, Bjorn Helgaas wrote:
> From: Michael S. Tsirkin <mst@xxxxxxxxxx>
>
> d52877c7b1af ("pci/irq: let pci_device_shutdown to call pci_msi_shutdown
> v2") disabled MSI/MSI-X at device shutdown to address a kexec problem.
>
> The problem is that after we disable MSI, the device may assert INTx, and
> if the driver hasn't registered an interrupt handler for it, the interrupt
> is never deasserted and causes a kernel hang.
I think we should drop "and causes a kernel hang" from this sentence:
most configurations can work around this by disabling the irq
line in the apic.
> In particular, this was
> observed with virtio.
>
> We now disable MSI/MSI-X for all devices during enumeration regardless of
> CONFIG_PCI_MSI. This solves the kexec problem in the new kernel, not the
> old one.
>
> Stop disabling MSIs at shutdown to avoid the kernel hang.
And replace this one with:
Stop disabling MSIs at shutdown to avoid conflicting with
drivers.
> XXX bugzilla reference, details about how the hang happens?
Add:
See bugzilla https://bugzilla.kernel.org/show_bug.cgi?id=96571
(that one's for a kernel that lacks
1e77d0a1ed7417d2a5a52a7b8d32aea1833faa6c, so
it doesn't recover by disabling the irq line).
>
> [bhelgaas: changelog]
> Reported-by: Fam Zheng <famz@xxxxxxxxxx>
> Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> CC: Yinghai Lu <yhlu.kernel.send@xxxxxxxxx>
> CC: Ulrich Obergfell <uobergfe@xxxxxxxxxx>
> CC: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
> ---
> drivers/pci/pci-driver.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
> index 3cb2210de553..38a602cb9fb7 100644
> --- a/drivers/pci/pci-driver.c
> +++ b/drivers/pci/pci-driver.c
> @@ -450,8 +450,6 @@ static void pci_device_shutdown(struct device *dev)
>
> if (drv && drv->shutdown)
> drv->shutdown(pci_dev);
> - pci_msi_shutdown(pci_dev);
> - pci_msix_shutdown(pci_dev);
>
> #ifdef CONFIG_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
