[+cc Rafael, Len, linux-acpi] Hi Mario, On Thu, Jun 01, 2023 at 10:11:22PM -0500, Mario Limonciello wrote: > ASMedia PCIe GPIO controllers connected to AMD SOC fail functional tests > after returning from s2idle. This is because the BIOS checks whether the > OSPM has called the _REG method to determine whether it can interact with > the OperationRegion assigned to the device. "s2idle" is a Linux term; I'd prefer something that we can relate to the ACPI spec. Maybe a pointer to the specific function in the driver that has a problem? Based on the patch, I assume the driver uses some control method that looks at PCI config space? > To fix this issue, call acpi_evaluate_reg() when saving and restoring the > state of PCI devices. Please include the spec citation: ACPI r6.5, sec 6.5.4. The URL has changed in the past and may change in the future, but the name/section number will not. > Link: https://uefi.org/htmlspecs/ACPI_Spec_6_4_html/06_Device_Configuration/Device_Configuration.html#reg-region > Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx> > --- > drivers/pci/pci.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index e38c2f6eebd4..071ecba548b0 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -1068,6 +1068,12 @@ static inline bool platform_pci_bridge_d3(struct pci_dev *dev) > return acpi_pci_bridge_d3(dev); > } > > +static inline int platform_toggle_reg(struct pci_dev *dev, int c) > +{ > + return acpi_evaluate_reg(ACPI_HANDLE(&dev->dev), > + ACPI_ADR_SPACE_PCI_CONFIG, c); > +} You never check the return value, so why return it? The function actually doesn't *toggle*; it connects or disconnects based on "c". This looks like it only builds when CONFIG_ACPI=y? > /** > * pci_update_current_state - Read power state of given device and cache it > * @dev: PCI device to handle. > @@ -1645,6 +1651,9 @@ static void pci_restore_ltr_state(struct pci_dev *dev) > int pci_save_state(struct pci_dev *dev) > { > int i; > + > + platform_toggle_reg(dev, ACPI_REG_DISCONNECT); I would expect these to be in the PM code near the power state transitions, not in the state save/restore code. These functions *are* used during suspend/resume, but are used in other places as well, where we probably don't want _REG executed. Cc'd Rafael and PM folks, who can give much better feedback. > /* XXX: 100% dword access ok here? */ > for (i = 0; i < 16; i++) { > pci_read_config_dword(dev, i * 4, &dev->saved_config_space[i]); > @@ -1790,6 +1799,8 @@ void pci_restore_state(struct pci_dev *dev) > pci_enable_acs(dev); > pci_restore_iov_state(dev); > > + platform_toggle_reg(dev, ACPI_REG_CONNECT); > + > dev->state_saved = false; > } > EXPORT_SYMBOL(pci_restore_state); > @@ -3203,6 +3214,7 @@ void pci_pm_init(struct pci_dev *dev) > pci_read_config_word(dev, PCI_STATUS, &status); > if (status & PCI_STATUS_IMM_READY) > dev->imm_ready = 1; > + platform_toggle_reg(dev, ACPI_REG_CONNECT); > } > > static unsigned long pci_ea_flags(struct pci_dev *dev, u8 prop) > -- > 2.34.1 >
