Hi,
> Hi,
>
> On 7/9/19 1:00 AM, Patel, Mayurkumar wrote:
> > After system suspend/resume cycle AER registers settings are
> > lost. Not restoring Root Error Command Register bits if it were
> > set, keeps AER interrupts disabled after system resume.
> > Moreover, AER mask and severity registers are also required
> > to be restored back to AER settings prior to system suspend.
> >
> > Signed-off-by: Mayurkumar Patel <mayurkumar.patel@xxxxxxxxx>
> > ---
> > drivers/pci/pci.c | 2 ++
> > drivers/pci/pcie/aer.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
> > include/linux/aer.h | 4 ++++
> > 3 files changed, 55 insertions(+)
> >
> > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > index 8abc843..40d5507 100644
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -1340,6 +1340,7 @@ int pci_save_state(struct pci_dev *dev)
> >
> > pci_save_ltr_state(dev);
> > pci_save_dpc_state(dev);
> > + pci_save_aer_state(dev);
> > return pci_save_vc_state(dev);
> > }
> > EXPORT_SYMBOL(pci_save_state);
> > @@ -1453,6 +1454,7 @@ void pci_restore_state(struct pci_dev *dev)
> > pci_restore_dpc_state(dev);
> >
> > pci_cleanup_aer_error_status_regs(dev);
> > + pci_restore_aer_state(dev);
> >
> > pci_restore_config_space(dev);
> >
> > diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
> > index b45bc47..1acc641 100644
> > --- a/drivers/pci/pcie/aer.c
> > +++ b/drivers/pci/pcie/aer.c
> > @@ -448,6 +448,54 @@ int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
> > return 0;
> > }
> >
> > +void pci_save_aer_state(struct pci_dev *dev)
> > +{
> > + int pos = 0;
> > + struct pci_cap_saved_state *save_state;
> > + u32 *cap;
> > +
> > + if (!pci_is_pcie(dev))
> > + return;
> > +
> > + save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_ERR);
> > + if (!save_state)
> > + return;
> > +
> > + pos = dev->aer_cap;
> > + if (!pos)
> > + return;
> > +
> > + cap = &save_state->cap.data[0];
> > + pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_MASK, cap++);
> > + pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_SEVER, cap++);
> > + pci_read_config_dword(dev, pos + PCI_ERR_COR_MASK, cap++);
> > + pci_read_config_dword(dev, pos + PCI_ERR_ROOT_COMMAND, cap++);
>
> I don't see AER driver modifying UNCOR_MASK/SEVER/COR_MASK register. If
> all it has is default value then why do you want to preserve it ?
>
Thanks for reply.
You are right about UNCOR_MASK/SEVER/COR_MASK mask AER driver leaves untouched,
But IMHO users for example can use "setpci" to unmask specific errors and its severity based on
their debugging requirement on Root port and/or Endpoint. So during resume, if PCIe endpoint
fails due to any error which by default stays masked then it can't be catched and/or debugged.
Moreover, Endpoint driver may also unmask during "driver probe" certain specific
errors for endpoint, which needs to be restored while resume.
@Bjorn/Anybody else has any opinion to cache/restore UNCOR_MASK/SEVER/COR_MASK registers?
Please help to comment.
> Also, any reason for not preserving ECRC settings ?
No specific reason. I can incorporte that with v2 of this patchset but I don’t have HW on which I can validate that.
>
> > +}
> > +
> > +void pci_restore_aer_state(struct pci_dev *dev)
> > +{
> > + int pos = 0;
> > + struct pci_cap_saved_state *save_state;
> > + u32 *cap;
> > +
> > + if (!pci_is_pcie(dev))
> > + return;
> > +
> > + save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_ERR);
> > + if (!save_state)
> > + return;
> > +
> > + pos = dev->aer_cap;
> > + if (!pos)
> > + return;
> > +
> > + cap = &save_state->cap.data[0];
> > + pci_write_config_dword(dev, pos + PCI_ERR_UNCOR_MASK, *cap++);
> > + pci_write_config_dword(dev, pos + PCI_ERR_UNCOR_SEVER, *cap++);
> > + pci_write_config_dword(dev, pos + PCI_ERR_COR_MASK, *cap++);
> > + pci_write_config_dword(dev, pos + PCI_ERR_ROOT_COMMAND, *cap++);
> > +}
> > +
> > void pci_aer_init(struct pci_dev *dev)
> > {
> > dev->aer_cap = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
> > @@ -1396,6 +1444,7 @@ static int aer_probe(struct pcie_device *dev)
> > return status;
> > }
> >
> > + pci_add_ext_cap_save_buffer(port, PCI_EXT_CAP_ID_ERR, sizeof(u32) * 4);
> > aer_enable_rootport(rpc);
> > pci_info(port, "enabled with IRQ %d\n", dev->irq);
> > return 0;
> > diff --git a/include/linux/aer.h b/include/linux/aer.h
> > index 514bffa..fa19e01 100644
> > --- a/include/linux/aer.h
> > +++ b/include/linux/aer.h
> > @@ -46,6 +46,8 @@ int pci_enable_pcie_error_reporting(struct pci_dev *dev);
> > int pci_disable_pcie_error_reporting(struct pci_dev *dev);
> > int pci_cleanup_aer_uncorrect_error_status(struct pci_dev *dev);
> > int pci_cleanup_aer_error_status_regs(struct pci_dev *dev);
> > +void pci_save_aer_state(struct pci_dev *dev);
> > +void pci_restore_aer_state(struct pci_dev *dev);
> > #else
> > static inline int pci_enable_pcie_error_reporting(struct pci_dev *dev)
> > {
> > @@ -63,6 +65,8 @@ static inline int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
> > {
> > return -EINVAL;
> > }
> > +static inline void pci_save_aer_state(struct pci_dev *dev) {}
> > +static inline void pci_restore_aer_state(struct pci_dev *dev) {}
> > #endif
> >
> > void cper_print_aer(struct pci_dev *dev, int aer_severity,
>
> --
> Sathyanarayanan Kuppuswamy
> Linux kernel developer
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