On Thu, 2010-06-03 at 17:45 -0700, Brad Peters wrote:
> Patch Overview:
> The pci_restore_state API is shared by both power management code and Extended
> Error Handling (EEH) code on Power. This patch adds an additional recovery
> function to pci_restore_state API. The problem being addressed is that Power
> Management semantics only allow the saved state of PCI device to be restored
> once per save. With this patch, EEH is able to restore the saved state
> each time a PCI error is detected, enabling recovery in the face of repeated
> errors.
You should at the very least send that to the PCI maintainer (Jesse
Barnes), though I would recommend the linux-pci list and CC lkml.
Cheers,
Ben.
> There was some discussion of renaming the existing and new functions to more
> clearly break out unconditional restore from the default conditional one, but
> a
> name change seemed a heavy-handed change to force on the 200+ current users.
>
> Bit more detail:
> PCI device drivers which support EEH/AER save their pci state once during
> driver initialization and during EEH/AER error recovery, restore the
> original saved state. What we found was that our pci driver code would
> recover from the first EEH error and fail to recover on subsequent
> EEH errors. This issue results from pci_restore_state() function
> restoring the state during initialization on the first EEH error.
>
> What this patch does is to provide the pci_force_restore_state() for use
> by PCI drivers which support EEH/AER that require the original saved
> state be restored each time an EEH/AER error is detected.
>
>
> Signed-off by: Brad Peters <bpet...@us.ibm.com>
> Signed-off by: Richard A Lary <rl...@linux.vnet.ibm.com>
>
> --
> Brad Peters
> IBM
> Linux on System-P Platform Serviceability Team Lead
> bpet...@linux.vnet.ibm.com
>
>
> -----------------
>
>
> diff -uNrp -X linux-2.6.34/Documentation/dontdiff
> linux-2.6.34.orig/drivers/pci/pci.c linux-2.6.34/drivers/pci/pci.c
> --- linux-2.6.34.orig/drivers/pci/pci.c 2010-05-16 14:17:36.000000000
> -0700
> +++ linux-2.6.34/drivers/pci/pci.c 2010-05-26 17:16:20.000000000 -0700
> @@ -920,19 +920,11 @@ pci_save_state(struct pci_dev *dev)
> return 0;
> }
>
> -/**
> - * pci_restore_state - Restore the saved state of a PCI device
> - * @dev: - PCI device that we're dealing with
> - */
> -int
> -pci_restore_state(struct pci_dev *dev)
> +static void __pci_restore_state(struct pci_dev *dev)
> {
> int i;
> u32 val;
>
> - if (!dev->state_saved)
> - return 0;
> -
> /* PCI Express register must be restored first */
> pci_restore_pcie_state(dev);
>
> @@ -953,12 +945,44 @@ pci_restore_state(struct pci_dev *dev)
> pci_restore_pcix_state(dev);
> pci_restore_msi_state(dev);
> pci_restore_iov_state(dev);
> +}
> +
> +
> +/**
> + * pci_restore_state - Restore the saved state of a PCI device
> + * only if dev->state_saved is not 0. Used by
> + * power management suspend/restore routines.
> + * @dev: - PCI device that we're dealing with
> + */
> +int
> +pci_restore_state(struct pci_dev *dev)
> +{
> +
> + if (!dev->state_saved)
> + return 0;
> +
> + __pci_restore_state(dev);
>
> dev->state_saved = false;
>
> return 0;
> }
>
> +/**
> + * pci_force_restore_state - Restore the saved state of a PCI device
> + * even if dev->state_saved is 0. Used by
> + * EEH and AER PCI error recovery.
> + * @dev: - PCI device that we're dealing with
> + */
> +int
> +pci_force_restore_state(struct pci_dev *dev)
> +{
> + __pci_restore_state(dev);
> +
> + return 0;
> +}
> +
> +
>
> static int do_pci_enable_device(struct pci_dev *dev, int bars)
> {
> int err;
> @@ -3039,6 +3063,7 @@ EXPORT_SYMBOL(pci_select_bars);
> EXPORT_SYMBOL(pci_set_power_state);
> EXPORT_SYMBOL(pci_save_state);
> EXPORT_SYMBOL(pci_restore_state);
> +EXPORT_SYMBOL(pci_force_restore_state);
> EXPORT_SYMBOL(pci_pme_capable);
> EXPORT_SYMBOL(pci_pme_active);
> EXPORT_SYMBOL(pci_wake_from_d3);
> diff -uNrp -X linux-2.6.34/Documentation/dontdiff
> linux-2.6.34.orig/include/linux/pci.h linux-2.6.34/include/linux/pci.h
> --- linux-2.6.34.orig/include/linux/pci.h 2010-05-16 14:17:36.000000000
> -0700
> +++ linux-2.6.34/include/linux/pci.h 2010-05-26 17:16:21.000000000 -0700
> @@ -792,6 +792,7 @@ size_t pci_get_rom_size(struct pci_dev *
> /* Power management related routines */
> int pci_save_state(struct pci_dev *dev);
> int pci_restore_state(struct pci_dev *dev);
> +int pci_force_restore_state(struct pci_dev *dev);
> int __pci_complete_power_transition(struct pci_dev *dev, pci_power_t state);
> int pci_set_power_state(struct pci_dev *dev, pci_power_t state);
> pci_power_t pci_choose_state(struct pci_dev *dev, pm_message_t state);
> @@ -1155,6 +1156,11 @@ static inline int pci_restore_state(stru
> return 0;
> }
>
> +static inline int pci_force_restore_state(struct pci_dev *dev)
> +{
> + return 0;
> +}
> +
> static inline int pci_set_power_state(struct pci_dev *dev, pci_power_t state)
> {
> return 0;
>
>
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> Linuxppc-dev@lists.ozlabs.org
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