This patch fixes the following bug: http://marc.info/?l=linux-pci&m=134338059022620&w=2 Where lspci does not work properly if a device and the corresponding parent bridge (such as PCIe port) is suspended. This is because the device configuration space registers will be not accessible if the corresponding parent bridge is suspended or the device is put into D3cold state. To solve the issue, the bridge/PCIe port connected to the device is put into active state before read/write configuration space registers. If the device is in D3cold state, it will be put into active state too. To avoid resume/suspend PCIe port for each configuration register read/write, a small delay is added before the PCIe port to go suspended. Reported-by: Bjorn Mork <bjorn@xxxxxxx> Signed-off-by: Huang Ying <ying.huang@xxxxxxxxx> --- drivers/pci/pci-sysfs.c | 42 +++++++++++++++++++++++++++++++++++++++++ drivers/pci/pcie/portdrv_pci.c | 9 ++++++++ 2 files changed, 51 insertions(+) --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -458,6 +458,40 @@ boot_vga_show(struct device *dev, struct } struct device_attribute vga_attr = __ATTR_RO(boot_vga); +static void +pci_config_pm_runtime_get(struct pci_dev *pdev) +{ + struct device *dev = &pdev->dev; + struct device *parent = dev->parent; + + if (parent) + pm_runtime_get_sync(parent); + pm_runtime_get_noresume(dev); + /* + * pdev->current_state is set to PCI_D3cold during suspending, + * so wait until suspending completes + */ + pm_runtime_barrier(dev); + /* + * Only need to resume devices in D3cold, because config + * registers are still accessible for devices suspended but + * not in D3cold. + */ + if (pdev->current_state == PCI_D3cold) + pm_runtime_resume(dev); +} + +static void +pci_config_pm_runtime_put(struct pci_dev *pdev) +{ + struct device *dev = &pdev->dev; + struct device *parent = dev->parent; + + pm_runtime_put(dev); + if (parent) + pm_runtime_put_sync(parent); +} + static ssize_t pci_read_config(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, @@ -484,6 +518,8 @@ pci_read_config(struct file *filp, struc size = count; } + pci_config_pm_runtime_get(dev); + if ((off & 1) && size) { u8 val; pci_user_read_config_byte(dev, off, &val); @@ -529,6 +565,8 @@ pci_read_config(struct file *filp, struc --size; } + pci_config_pm_runtime_put(dev); + return count; } @@ -549,6 +587,8 @@ pci_write_config(struct file* filp, stru count = size; } + pci_config_pm_runtime_get(dev); + if ((off & 1) && size) { pci_user_write_config_byte(dev, off, data[off - init_off]); off++; @@ -587,6 +627,8 @@ pci_write_config(struct file* filp, stru --size; } + pci_config_pm_runtime_put(dev); + return count; } --- a/drivers/pci/pcie/portdrv_pci.c +++ b/drivers/pci/pcie/portdrv_pci.c @@ -140,9 +140,17 @@ static int pcie_port_runtime_resume(stru { return 0; } + +static int pcie_port_runtime_idle(struct device *dev) +{ + /* Delay for a short while to prevent too frequent suspend/resume */ + pm_schedule_suspend(dev, 10); + return -EBUSY; +} #else #define pcie_port_runtime_suspend NULL #define pcie_port_runtime_resume NULL +#define pcie_port_runtime_idle NULL #endif static const struct dev_pm_ops pcie_portdrv_pm_ops = { @@ -155,6 +163,7 @@ static const struct dev_pm_ops pcie_port .resume_noirq = pcie_port_resume_noirq, .runtime_suspend = pcie_port_runtime_suspend, .runtime_resume = pcie_port_runtime_resume, + .runtime_idle = pcie_port_runtime_idle, }; #define PCIE_PORTDRV_PM_OPS (&pcie_portdrv_pm_ops) -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
