1 files changed, 42 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;
 }