e1000e: Disable L1 ASPM power savings for 82573 mobile variants

L1 ASPM link (pci-e link power savings) has significant benefits
(~1W savings when link is active) but unfortunately does not work
correctly on any of the chipsets that have 82573 on mobile platforms
which causes various nuisances:
 - eeprom reads return garbage information leading to bad eeprom
   checksums
 - long ping times (up to 2 seconds)
 - complete system hangs (freeze/lockup)

A lot of T60 owners have been plagued by this, but other mobile
solutions also suffer from these symptoms.

Disabling L1 ASPM before we activate the PCI-E link fixes all of
these issues at the cost of some power consumption.

Remove a workaround RDTR adjustment that is no longer needed with
this new one.

Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 30 insertions, 0 deletions

diff --git a/drivers/net/e1000e/netdev.c b/drivers/net/e1000e/netdev.c
index 9cc5a6b01bc1..5450ef8bf881 100644
--- a/drivers/net/e1000e/netdev.c
+++ b/drivers/net/e1000e/netdev.c
@@ -3509,6 +3509,33 @@ static int e1000_suspend(struct pci_dev *pdev, pm_message_t state)
         return 0;
 }
 
+static void e1000e_disable_l1aspm(struct pci_dev *pdev)
+{
+        int pos;
+        u32 cap;
+        u16 val;
+
+        /*
+         * 82573 workaround - disable L1 ASPM on mobile chipsets
+         *
+         * L1 ASPM on various mobile (ich7) chipsets do not behave properly
+         * resulting in lost data or garbage information on the pci-e link
+         * level. This could result in (false) bad EEPROM checksum errors,
+         * long ping times (up to 2s) or even a system freeze/hang.
+         *
+         * Unfortunately this feature saves about 1W power consumption when
+         * active.
+         */
+        pos = pci_find_capability(pdev, PCI_CAP_ID_EXP);
+        pci_read_config_dword(pdev, pos + PCI_EXP_LNKCAP, &cap);
+        pci_read_config_word(pdev, pos + PCI_EXP_LNKCTL, &val);
+        if (val & 0x2) {
+                dev_warn(&pdev->dev, "Disabling L1 ASPM\n");
+                val &= ~0x2;
+                pci_write_config_word(pdev, pos + PCI_EXP_LNKCTL, val);
+        }
+}
+
 #ifdef CONFIG_PM
 static int e1000_resume(struct pci_dev *pdev)
 {
@@ -3519,6 +3546,7 @@ static int e1000_resume(struct pci_dev *pdev)
 
         pci_set_power_state(pdev, PCI_D0);
         pci_restore_state(pdev);
+        e1000e_disable_l1aspm(pdev);
         err = pci_enable_device(pdev);
         if (err) {
                 dev_err(&pdev->dev,
@@ -3619,6 +3647,7 @@ static pci_ers_result_t e1000_io_slot_reset(struct pci_dev *pdev)
         struct e1000_adapter *adapter = netdev_priv(netdev);
         struct e1000_hw *hw = &adapter->hw;
 
+        e1000e_disable_l1aspm(pdev);
         if (pci_enable_device(pdev)) {
                 dev_err(&pdev->dev,
                         "Cannot re-enable PCI device after reset.\n");
@@ -3720,6 +3749,7 @@ static int __devinit e1000_probe(struct pci_dev *pdev,
         u16 eeprom_data = 0;
         u16 eeprom_apme_mask = E1000_EEPROM_APME;
 
+        e1000e_disable_l1aspm(pdev);
         err = pci_enable_device(pdev);
         if (err)
                 return err;