On Sunday 08 March 2009, Yinghai Lu wrote:
>
> Impact: second kernel by kexec will have some pci devices working
>
> Found one system with 82575EB, in the kernel that is kexeced, probe igb
> failed with -2.
>
> it looks like the same behavior happened on forcedeth.
> try to check system_state to make sure if put it on D3
This is not enough, because the PM code doesn't change system_state and
it uses pci_set_power_state too.
> Jesse Brandeburg said that we should do that check in core code instead of
> every device driver.
Well, I'm not really sure. The drivers are where the bug is.
> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
>
> ---
> drivers/pci/pci.c | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> Index: linux-2.6/drivers/pci/pci.c
> ===================================================================
> --- linux-2.6.orig/drivers/pci/pci.c
> +++ linux-2.6/drivers/pci/pci.c
> @@ -593,6 +593,14 @@ int pci_set_power_state(struct pci_dev *
> if (state == PCI_D3hot && (dev->dev_flags & PCI_DEV_FLAGS_NO_D3))
> return 0;
>
> + /*
> + * Apparently it is not possible to reinitialise from D3 hot,
> + * only put the device into D3 if we really go for poweroff.
> + */
> + if (system_state != SYSTEM_POWER_OFF &&
> + (state == PCI_D3hot || state == PCI_D3cold))
> + return 0;
> +
This breaks suspend/hibernation, doesn't it? Surely, we want to put devices
into D3 when going for suspend, for example.
That's apart from the fact that the 'state == PCI_D3cold' is redundant.
> error = pci_raw_set_power_state(dev, state, true);
>
> if (state > PCI_D0 && platform_pci_power_manageable(dev)) {
> @@ -1124,6 +1132,15 @@ int pci_enable_wake(struct pci_dev *dev,
> int error = 0;
> bool pme_done = false;
>
> + /*
> + * Apparently it is not possible to reinitialise from D3 hot,
> + * only put the device into D3 if we really go for poweroff.
> + * we only need to enable wake when we are going to power off
> + */
> + if (enable && system_state != SYSTEM_POWER_OFF &&
> + (state == PCI_D3hot || state == PCI_D3cold))
> + return 0;
> +
> if (enable && !device_may_wakeup(&dev->dev))
> return -EINVAL;
I don't like this at all, sorry.
I thought we were supposed to avoid using system_state in such a way,
apart from the other things.
Thanks,
Rafael
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