On Mon, May 12, 2025 at 01:56:06PM +0200, Rafael J. Wysocki wrote: > On Sun, May 4, 2025 at 11:06 AM Raag Jadav <raag.jadav@xxxxxxxxx> wrote: > > > > If error flags are set on an AER capable device, most likely either the > > device recovery is in progress or has already failed. Neither of the > > cases are well suited for power state transition of the device, since > > this can lead to unpredictable consequences like resume failure, or in > > worst case the device is lost because of it. Leave the device in its > > existing power state to avoid such issues. > > > > Signed-off-by: Raag Jadav <raag.jadav@xxxxxxxxx> > > --- > > > > v2: Synchronize AER handling with PCI PM (Rafael) > > v3: Move pci_aer_in_progress() to pci_set_low_power_state() (Rafael) > > Elaborate "why" (Bjorn) > > I think this is reasonable, so > > Acked-by: Rafael J. Wysocki <rafael@xxxxxxxxxx> Thank you! > (and you might as well CC it to linux-pm@xxxxxxxxxxxxxxx>). Cc'ing linux-pm list as requested by Rafael. > > More discussion on [1]. > > [1] https://lore.kernel.org/all/CAJZ5v0g-aJXfVH+Uc=9eRPuW08t-6PwzdyMXsC6FZRKYJtY03Q@xxxxxxxxxxxxxx/ > > > > drivers/pci/pci.c | 12 ++++++++++++ > > drivers/pci/pcie/aer.c | 11 +++++++++++ > > include/linux/aer.h | 2 ++ > > 3 files changed, 25 insertions(+) > > > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > > index 4d7c9f64ea24..25b2df34336c 100644 > > --- a/drivers/pci/pci.c > > +++ b/drivers/pci/pci.c > > @@ -9,6 +9,7 @@ > > */ > > > > #include <linux/acpi.h> > > +#include <linux/aer.h> > > #include <linux/kernel.h> > > #include <linux/delay.h> > > #include <linux/dmi.h> > > @@ -1539,6 +1540,17 @@ static int pci_set_low_power_state(struct pci_dev *dev, pci_power_t state, bool > > || (state == PCI_D2 && !dev->d2_support)) > > return -EIO; > > > > + /* > > + * If error flags are set on an AER capable device, most likely either > > + * the device recovery is in progress or has already failed. Neither of > > + * the cases are well suited for power state transition of the device, > > + * since this can lead to unpredictable consequences like resume > > + * failure, or in worst case the device is lost because of it. Leave the > > + * device in its existing power state to avoid such issues. > > + */ > > + if (pci_aer_in_progress(dev)) > > + return -EIO; > > + > > pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr); > > if (PCI_POSSIBLE_ERROR(pmcsr)) { > > pci_err(dev, "Unable to change power state from %s to %s, device inaccessible\n", > > diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c > > index a1cf8c7ef628..4040770df4f0 100644 > > --- a/drivers/pci/pcie/aer.c > > +++ b/drivers/pci/pcie/aer.c > > @@ -237,6 +237,17 @@ int pcie_aer_is_native(struct pci_dev *dev) > > } > > EXPORT_SYMBOL_NS_GPL(pcie_aer_is_native, "CXL"); > > > > +bool pci_aer_in_progress(struct pci_dev *dev) > > +{ > > + u16 reg16; > > + > > + if (!pcie_aer_is_native(dev)) > > + return false; > > + > > + pcie_capability_read_word(dev, PCI_EXP_DEVSTA, ®16); > > + return !!(reg16 & PCI_EXP_AER_FLAGS); > > +} > > + > > static int pci_enable_pcie_error_reporting(struct pci_dev *dev) > > { > > int rc; > > diff --git a/include/linux/aer.h b/include/linux/aer.h > > index 02940be66324..e6a380bb2e68 100644 > > --- a/include/linux/aer.h > > +++ b/include/linux/aer.h > > @@ -56,12 +56,14 @@ struct aer_capability_regs { > > #if defined(CONFIG_PCIEAER) > > int pci_aer_clear_nonfatal_status(struct pci_dev *dev); > > int pcie_aer_is_native(struct pci_dev *dev); > > +bool pci_aer_in_progress(struct pci_dev *dev); > > #else > > static inline int pci_aer_clear_nonfatal_status(struct pci_dev *dev) > > { > > return -EINVAL; > > } > > static inline int pcie_aer_is_native(struct pci_dev *dev) { return 0; } > > +static inline bool pci_aer_in_progress(struct pci_dev *dev) { return false; } > > #endif > > > > void pci_print_aer(struct pci_dev *dev, int aer_severity, > > -- > > 2.34.1 > >
