1 files changed, 29 insertions, 3 deletions

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index f82495583e63..9a7c9e1408a4 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -55,7 +55,7 @@ struct pcie_link_state {
         struct endpoint_state endpoints[8];
 };
 
-static int aspm_disabled;
+static int aspm_disabled, aspm_force;
 static DEFINE_MUTEX(aspm_lock);
 static LIST_HEAD(link_list);
 
@@ -510,6 +510,7 @@ static int pcie_aspm_sanity_check(struct pci_dev *pdev)
 {
         struct pci_dev *child_dev;
         int child_pos;
+        u32 reg32;
 
         /*
          * Some functions in a slot might not all be PCIE functions, very
@@ -519,6 +520,19 @@ static int pcie_aspm_sanity_check(struct pci_dev *pdev)
                 child_pos = pci_find_capability(child_dev, PCI_CAP_ID_EXP);
                 if (!child_pos)
                         return -EINVAL;
+
+                /*
+                 * Disable ASPM for pre-1.1 PCIe device, we follow MS to use
+                 * RBER bit to determine if a function is 1.1 version device
+                 */
+                pci_read_config_dword(child_dev, child_pos + PCI_EXP_DEVCAP,
+                        &reg32);
+                if (!(reg32 & PCI_EXP_DEVCAP_RBER && !aspm_force)) {
+                        printk("Pre-1.1 PCIe device detected, "
+                                "disable ASPM for %s. It can be enabled forcedly"
+                                " with 'pcie_aspm=force'\n", pci_name(pdev));
+                        return -EINVAL;
+                }
         }
         return 0;
 }
@@ -802,11 +816,23 @@ void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev)
 
 static int __init pcie_aspm_disable(char *str)
 {
-        aspm_disabled = 1;
+        if (!strcmp(str, "off")) {
+                aspm_disabled = 1;
+                printk(KERN_INFO "PCIe ASPM is disabled\n");
+        } else if (!strcmp(str, "force")) {
+                aspm_force = 1;
+                printk(KERN_INFO "PCIe ASPM is forcedly enabled\n");
+        }
         return 1;
 }
 
-__setup("pcie_noaspm", pcie_aspm_disable);
+__setup("pcie_aspm=", pcie_aspm_disable);
+
+void pcie_no_aspm(void)
+{
+        if (!aspm_force)
+                aspm_disabled = 1;
+}
 
 #ifdef CONFIG_ACPI
 #include <acpi/acpi_bus.h>