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authorJouni Malinen <jouni.malinen@atheros.com>2009-06-16 11:59:23 +0300
committerGreg Kroah-Hartman <gregkh@suse.de>2009-07-02 16:50:18 -0700
commit241798adc59d1d79c783bb4726f595ab97fb6595 (patch)
treeee3d7cb03cc4bdd49babf53da52964ddee4f6ed1
parentd0c154d59bbdca8317241e7cc51c319bf216662d (diff)
ath9k: Fix PCI FATAL interrupts by restoring RETRY_TIMEOUT disabling
commit f0214843ba23d9bf6dc6b8ad2c6ee27b60f0322e upstream. An earlier commit, 'ath9k: remove dummy PCI "retry timeout" fix', removed code that was documented to disable RETRY_TIMEOUT register (PCI reg 0x41) since it was claimed to be a no-op. However, it turns out that there are some combinations of hosts and ath9k-supported cards for which this is not a no-op (reg 0x41 has value 0x80, not 0) and this code (or something similar) is needed. In such cases, the driver may be next to unusable due to very frequent PCI FATAL interrupts from the card. Reverting the earlier commit, i.e., restoring the RETRY_TIMEOUT disabling, seems to resolve the issue. Since the removal of this code was not based on any known issue and was purely a cleanup change, the safest option here is to just revert that commit. Should there be desire to clean this up in the future, the change will need to be tested with a more complete coverage of cards and host systems. http://bugzilla.kernel.org/show_bug.cgi?id=13483 Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com> Signed-off-by: John W. Linville <linville@tuxdriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--drivers/net/wireless/ath9k/pci.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/drivers/net/wireless/ath9k/pci.c b/drivers/net/wireless/ath9k/pci.c
index 168411d322a2..4affb49702d8 100644
--- a/drivers/net/wireless/ath9k/pci.c
+++ b/drivers/net/wireless/ath9k/pci.c
@@ -87,6 +87,7 @@ static int ath_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
struct ath_softc *sc;
struct ieee80211_hw *hw;
u8 csz;
+ u32 val;
int ret = 0;
struct ath_hw *ah;
@@ -133,6 +134,14 @@ static int ath_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
pci_set_master(pdev);
+ /*
+ * Disable the RETRY_TIMEOUT register (0x41) to keep
+ * PCI Tx retries from interfering with C3 CPU state.
+ */
+ pci_read_config_dword(pdev, 0x40, &val);
+ if ((val & 0x0000ff00) != 0)
+ pci_write_config_dword(pdev, 0x40, val & 0xffff00ff);
+
ret = pci_request_region(pdev, 0, "ath9k");
if (ret) {
dev_err(&pdev->dev, "PCI memory region reserve error\n");
@@ -244,12 +253,21 @@ static int ath_pci_resume(struct pci_dev *pdev)
struct ieee80211_hw *hw = pci_get_drvdata(pdev);
struct ath_wiphy *aphy = hw->priv;
struct ath_softc *sc = aphy->sc;
+ u32 val;
int err;
err = pci_enable_device(pdev);
if (err)
return err;
pci_restore_state(pdev);
+ /*
+ * Suspend/Resume resets the PCI configuration space, so we have to
+ * re-disable the RETRY_TIMEOUT register (0x41) to keep
+ * PCI Tx retries from interfering with C3 CPU state
+ */
+ pci_read_config_dword(pdev, 0x40, &val);
+ if ((val & 0x0000ff00) != 0)
+ pci_write_config_dword(pdev, 0x40, val & 0xffff00ff);
/* Enable LED */
ath9k_hw_cfg_output(sc->sc_ah, ATH_LED_PIN,