[..] 
> If there's patch, I'll gladly try it :-). Thanks,
> 
								Pavel
Thanks Pavel,

It ended up taking more time than I thought.  The checking of whether ASPM is really enabled or not is, unfortunately, not as straightforward as I thought initially, so we ended up rewriting the function a bit.  In this patch we try to use the pci_disable_link_state_locked() call, but if it fails, we then write to pci config space of the device to disable it.

Please let me know if this actually disables the ASPM for your 82574 parts or not.  We can still continue the discussion on whether this is the best approach or not, or what else could be done.

This patch attempts to work around a problem found with some systems where the call to pci_diable_link_state_locked() fails.  As a result, ASPM is not, in fact, disabled.  Changing disable aspm code to check if state actually is disabled after the call and, if not, try another way to disable it.

Signed-off-by: Carolyn Wyborny <carolyn.wyborny@intel.com>
---

 drivers/net/ethernet/intel/e1000e/netdev.c |   86 ++++++++++++++++++++--------
 1 files changed, 60 insertions(+), 26 deletions(-)

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index e6d2c0f..bc3025b 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -64,8 +64,6 @@ static int debug = -1;  module_param(debug, int, 0);  MODULE_PARM_DESC(debug, "Debug level (0=none,...,16=all)");
 
-static void e1000e_disable_aspm(struct pci_dev *pdev, u16 state);
-
 static const struct e1000_info *e1000_info_tbl[] = {
 	[board_82571]		= &e1000_82571_info,
 	[board_82572]		= &e1000_82572_info,
@@ -6019,38 +6017,74 @@ static int __e1000_shutdown(struct pci_dev *pdev, bool runtime)
 	return 0;
 }
 
-#ifdef CONFIG_PCIEASPM
-static void __e1000e_disable_aspm(struct pci_dev *pdev, u16 state)
+/**
+ * e1000e_disable_aspm - Disable ASPM states
+ * @pdev: pointer to PCI device struct
+ * @state: bit-mask of ASPM states to disable
+ *
+ * Some devices *must* have certain ASPM states disabled per hardware errata.
+ **/
+static void e1000e_disable_aspm(struct pci_dev *pdev, u16 state)
 {
+	struct pci_dev *parent = pdev->bus->self;
+	u16 aspm_dis_mask = 0;
+	u16 pdev_aspmc, parent_aspmc;
+
+	switch (state) {
+	case PCIE_LINK_STATE_L0S:
+	case PCIE_LINK_STATE_L0S + PCIE_LINK_STATE_L1:
+		aspm_dis_mask |= PCI_EXP_LNKCTL_ASPM_L0S;
+		/* fall-through - can't have L1 without L0s */
+	case PCIE_LINK_STATE_L1:
+		aspm_dis_mask |= PCI_EXP_LNKCTL_ASPM_L1;
+		break;
+	default:
+		return;
+	}
+
+	pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &pdev_aspmc);
+	pdev_aspmc &= PCI_EXP_LNKCTL_ASPMC;
+
+	if (parent) {
+		pcie_capability_read_word(parent, PCI_EXP_LNKCTL,
+					  &parent_aspmc);
+		parent_aspmc &= PCI_EXP_LNKCTL_ASPMC;
+	}
+
+	/* Nothing to do if the ASPM states to be disabled already are */
+	if (!(pdev_aspmc & aspm_dis_mask) &&
+	    (!parent || !(parent_aspmc & aspm_dis_mask)))
+		return;
+
+	dev_info(&pdev->dev, "Disabling ASPM %s %s\n",
+		 (aspm_dis_mask & pdev_aspmc & PCI_EXP_LNKCTL_ASPM_L0S) ?
+		 "L0s" : "",
+		 (aspm_dis_mask & pdev_aspmc & PCI_EXP_LNKCTL_ASPM_L1) ?
+		 "L1" : "");
+
+#ifdef CONFIG_PCIEASPM
 	pci_disable_link_state_locked(pdev, state); -} -#else -static void __e1000e_disable_aspm(struct pci_dev *pdev, u16 state) -{
-	u16 aspm_ctl = 0;
 
-	if (state & PCIE_LINK_STATE_L0S)
-		aspm_ctl |= PCI_EXP_LNKCTL_ASPM_L0S;
-	if (state & PCIE_LINK_STATE_L1)
-		aspm_ctl |= PCI_EXP_LNKCTL_ASPM_L1;
+	/* Double-check ASPM control.  If not disabled by the above, the
+	 * BIOS is preventing that from happening (or CONFIG_PCIEASPM is
+	 * not enabled); override by writing PCI config space directly.
+	 */
+	pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &pdev_aspmc);
+	pdev_aspmc &= PCI_EXP_LNKCTL_ASPMC;
+
+	if (!(aspm_dis_mask & pdev_aspmc))
+		return;
+	}
+#endif
 
 	/* Both device and parent should have the same ASPM setting.
 	 * Disable ASPM in downstream component first and then upstream.
 	 */
-	pcie_capability_clear_word(pdev, PCI_EXP_LNKCTL, aspm_ctl);
-
-	if (pdev->bus->self)
-		pcie_capability_clear_word(pdev->bus->self, PCI_EXP_LNKCTL,
-					   aspm_ctl);
-}
-#endif
-static void e1000e_disable_aspm(struct pci_dev *pdev, u16 state) -{
-	dev_info(&pdev->dev, "Disabling ASPM %s %s\n",
-		 (state & PCIE_LINK_STATE_L0S) ? "L0s" : "",
-		 (state & PCIE_LINK_STATE_L1) ? "L1" : "");
+	pcie_capability_clear_word(pdev, PCI_EXP_LNKCTL, aspm_dis_mask);
 
-	__e1000e_disable_aspm(pdev, state);
+	if (parent)
+		pcie_capability_clear_word(parent, PCI_EXP_LNKCTL,
+					   aspm_dis_mask);
 }
 
 #ifdef CONFIG_PM