commit 149e16372a2066c5474d8a8db9b252afd57eb427
author Shaohua Li <shaohua.li@intel.com> Wed Jul 23 10:32:31 2008 +0800
committer Jesse Barnes <jbarnes@virtuousgeek.org> Mon Jul 28 14:56:57 2008 -0700
tree 075a46f0672739fdab18d2f1e5f06080160de8b0
parent 5fde244d39b88625ac578d83e6625138714de031

PCI: disable ASPM on pre-1.1 PCIe devices

Disable ASPM on pre-1.1 PCIe devices, as many of them don't implement it
correctly.

Tested-by: Jack Howarth <howarth@bromo.msbb.uc.edu>
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

drivers/pci/pcie/aspm.c

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 759c51a..7046052 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -510,6 +510,7 @@
 {
 	struct pci_dev *child_dev;
 	int child_pos;
+	u32 reg32;
 
 	/*
 	 * Some functions in a slot might not all be PCIE functions, very
@@ -519,6 +520,18 @@
 		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)) {
+			printk("Pre-1.1 PCIe device detected, "
+				"disable ASPM for %s\n", pci_name(pdev));
+			return -EINVAL;
+		}
 	}
 	return 0;
 }

drivers/pci/probe.c

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 2036300..7098dfb 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1057,7 +1057,8 @@
 		}
 	}
 
-	if (bus->self)
+	/* only one slot has pcie device */
+	if (bus->self && nr)
 		pcie_aspm_init_link_state(bus->self);
 
 	return nr;