[+cc Keith, Oza, who did quite a bit of recent AER work] Please see https://lkml.kernel.org/r/20171026223701.GA25649@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx for a few incidental subject line/commit log hints. On Wed, Jul 10, 2019 at 10:36:16AM -0700, sathyanarayanan kuppuswamy wrote: > On 7/10/19 10:22 AM, Patel, Mayurkumar wrote: > > > 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. > > Isn't these registers configuration usually done by firmware ? I > think user application rarely touch them. Also, IMO, > Caching/Restoring registers under the assumption that it might be > useful for user if they modified it is not a convincing argument. > But I will let Bjorn and others decide whether its alright to cache > these registers. I think the ideal user experience would be "suspend/resume has no effect on any configuration". That would argue for saving/restoring registers even if we think it's unlikely the user would change them. > > @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. I think we should preserve ECRC settings as well for the same reason. > > > > +} > > > > + > > > > +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 > > Intel Deutschland GmbH > > Registered Address: Am Campeon 10-12, 85579 Neubiberg, Germany > > Tel: +49 89 99 8853-0, www.intel.de > > Managing Directors: Christin Eisenschmid, Gary Kershaw > > Chairperson of the Supervisory Board: Nicole Lau > > Registered Office: Munich > > Commercial Register: Amtsgericht Muenchen HRB 186928 > > -- > Sathyanarayanan Kuppuswamy > Linux kernel developer >
