Merge branch 'fix/misc' into topic/misc

1 files changed, 21 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath/ath5k/base.c b/drivers/net/wireless/ath/ath5k/base.c
index 0d5de25..373dcfe 100644
--- a/drivers/net/wireless/ath/ath5k/base.c
+++ b/drivers/net/wireless/ath/ath5k/base.c
@@ -48,6 +48,7 @@
 #include <linux/netdevice.h>
 #include <linux/cache.h>
 #include <linux/pci.h>
+#include <linux/pci-aspm.h>
 #include <linux/ethtool.h>
 #include <linux/uaccess.h>
 #include <linux/slab.h>
@@ -476,6 +477,26 @@ ath5k_pci_probe(struct pci_dev *pdev,
 	int ret;
 	u8 csz;
 
+	/*
+	 * L0s needs to be disabled on all ath5k cards.
+	 *
+	 * For distributions shipping with CONFIG_PCIEASPM (this will be enabled
+	 * by default in the future in 2.6.36) this will also mean both L1 and
+	 * L0s will be disabled when a pre 1.1 PCIe device is detected. We do
+	 * know L1 works correctly even for all ath5k pre 1.1 PCIe devices
+	 * though but cannot currently undue the effect of a blacklist, for
+	 * details you can read pcie_aspm_sanity_check() and see how it adjusts
+	 * the device link capability.
+	 *
+	 * It may be possible in the future to implement some PCI API to allow
+	 * drivers to override blacklists for pre 1.1 PCIe but for now it is
+	 * best to accept that both L0s and L1 will be disabled completely for
+	 * distributions shipping with CONFIG_PCIEASPM rather than having this
+	 * issue present. Motivation for adding this new API will be to help
+	 * with power consumption for some of these devices.
+	 */
+	pci_disable_link_state(pdev, PCIE_LINK_STATE_L0S);
+
 	ret = pci_enable_device(pdev);
 	if (ret) {
 		dev_err(&pdev->dev, "can't enable device\n");