summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorHuang Ying <ying.huang@intel.com>2012-08-15 03:43:03 +0200
committerBjorn Helgaas <bhelgaas@google.com>2012-08-22 01:34:24 +0200
commit3d8387efe1ad9eb5bfe8a2e58cdbd1b88b247eef (patch)
treea589e0ab38c2ecda5aff3792b677bd2b0c06b718
parentPCI/PM: Keep parent bridge active when probing device (diff)
downloadlinux-3d8387efe1ad9eb5bfe8a2e58cdbd1b88b247eef.tar.xz
linux-3d8387efe1ad9eb5bfe8a2e58cdbd1b88b247eef.zip
PCI/PM: Fix config reg access for D3cold and bridge suspending
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@mork.no> Signed-off-by: Huang Ying <ying.huang@intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Rafael J. Wysocki <rjw@sisk.pl>
-rw-r--r--drivers/pci/pci-sysfs.c42
-rw-r--r--drivers/pci/pcie/portdrv_pci.c9
2 files changed, 51 insertions, 0 deletions
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 6869009c7393..02d107b15281 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -458,6 +458,40 @@ boot_vga_show(struct device *dev, struct device_attribute *attr, char *buf)
}
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, struct kobject *kobj,
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, struct kobject *kobj,
--size;
}
+ pci_config_pm_runtime_put(dev);
+
return count;
}
@@ -549,6 +587,8 @@ pci_write_config(struct file* filp, struct kobject *kobj,
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, struct kobject *kobj,
--size;
}
+ pci_config_pm_runtime_put(dev);
+
return count;
}
diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c
index 62f5a76c8f80..e76b44777dbf 100644
--- a/drivers/pci/pcie/portdrv_pci.c
+++ b/drivers/pci/pcie/portdrv_pci.c
@@ -140,9 +140,17 @@ static int pcie_port_runtime_resume(struct device *dev)
{
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_portdrv_pm_ops = {
.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)