1 files changed, 18 insertions, 4 deletions

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 0ec649d961d7..17ac1dce3286 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -351,12 +351,26 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
                 return;
         }
 
+        /* Get upstream/downstream components' register state */
+        pcie_get_aspm_reg(parent, &upreg);
+        child = list_entry(linkbus->devices.next, struct pci_dev, bus_list);
+        pcie_get_aspm_reg(child, &dwreg);
+
+        /*
+         * If ASPM not supported, don't mess with the clocks and link,
+         * bail out now.
+         */
+        if (!(upreg.support & dwreg.support))
+                return;
+
         /* Configure common clock before checking latencies */
         pcie_aspm_configure_common_clock(link);
 
-        /* Get upstream/downstream components' register state */
+        /*
+         * Re-read upstream/downstream components' register state
+         * after clock configuration
+         */
         pcie_get_aspm_reg(parent, &upreg);
-        child = list_entry(linkbus->devices.next, struct pci_dev, bus_list);
         pcie_get_aspm_reg(child, &dwreg);
 
         /*
@@ -886,8 +900,8 @@ static ssize_t clk_ctl_store(struct device *dev,
         return n;
 }
 
-static DEVICE_ATTR(link_state, 0644, link_state_show, link_state_store);
-static DEVICE_ATTR(clk_ctl, 0644, clk_ctl_show, clk_ctl_store);
+static DEVICE_ATTR_RW(link_state);
+static DEVICE_ATTR_RW(clk_ctl);
 
 static char power_group[] = "power";
 void pcie_aspm_create_sysfs_dev_files(struct pci_dev *pdev)