1 files changed, 17 insertions, 4 deletions

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 71222814c1ec..3188cd96b338 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -68,7 +68,7 @@ struct pcie_link_state {
         struct aspm_latency acceptable[8];
 };
 
-static int aspm_disabled, aspm_force;
+static int aspm_disabled, aspm_force, aspm_clear_state;
 static DEFINE_MUTEX(aspm_lock);
 static LIST_HEAD(link_list);
 
@@ -139,7 +139,7 @@ static void pcie_set_clkpm(struct pcie_link_state *link, int enable)
 {
         /* Don't enable Clock PM if the link is not Clock PM capable */
         if (!link->clkpm_capable && enable)
-                return;
+                enable = 0;
         /* Need nothing if the specified equals to current state */
         if (link->clkpm_enabled == enable)
                 return;
@@ -498,6 +498,10 @@ static int pcie_aspm_sanity_check(struct pci_dev *pdev)
         struct pci_dev *child;
         int pos;
         u32 reg32;
+
+        if (aspm_clear_state)
+                return -EINVAL;
+
         /*
          * Some functions in a slot might not all be PCIe functions,
          * very strange. Disable ASPM for the whole slot
@@ -563,12 +567,15 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev)
         struct pcie_link_state *link;
         int blacklist = !!pcie_aspm_sanity_check(pdev);
 
-        if (aspm_disabled || !pci_is_pcie(pdev) || pdev->link_state)
+        if (!pci_is_pcie(pdev) || pdev->link_state)
                 return;
         if (pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT &&
             pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM)
                 return;
 
+        if (aspm_disabled && !aspm_clear_state)
+                return;
+
         /* VIA has a strange chipset, root port is under a bridge */
         if (pdev->pcie_type == PCI_EXP_TYPE_ROOT_PORT &&
             pdev->bus->self)
@@ -641,7 +648,7 @@ void pcie_aspm_exit_link_state(struct pci_dev *pdev)
         struct pci_dev *parent = pdev->bus->self;
         struct pcie_link_state *link, *root, *parent_link;
 
-        if (aspm_disabled || !pci_is_pcie(pdev) ||
+        if ((aspm_disabled && !aspm_clear_state) || !pci_is_pcie(pdev) ||
             !parent || !parent->link_state)
                 return;
         if ((parent->pcie_type != PCI_EXP_TYPE_ROOT_PORT) &&
@@ -899,6 +906,12 @@ static int __init pcie_aspm_disable(char *str)
 
 __setup("pcie_aspm=", pcie_aspm_disable);
 
+void pcie_clear_aspm(void)
+{
+        if (!aspm_force)
+                aspm_clear_state = 1;
+}
+
 void pcie_no_aspm(void)
 {
         if (!aspm_force)