4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Felix Fietkau <nbd@xxxxxxxx> commit a34d0a0da1abae46a5f6ebd06fb0ec484ca099d9 upstream. In an RFC patch, Sven Eckelmann and Simon Wunderlich reported: "QCA 802.11n chips (especially AR9330/AR9340) sometimes end up in a state in which a read of AR_CFG always returns 0xdeadbeef. This should not happen when when the power_mode of the device is ATH9K_PM_AWAKE." Include the check for the default register state in the existing MAC hang check. Signed-off-by: Felix Fietkau <nbd@xxxxxxxx> Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxxxx> Cc: Amit Pundir <amit.pundir@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/wireless/ath/ath9k/hw.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/drivers/net/wireless/ath/ath9k/hw.c +++ b/drivers/net/wireless/ath/ath9k/hw.c @@ -1595,6 +1595,10 @@ bool ath9k_hw_check_alive(struct ath_hw int count = 50; u32 reg, last_val; + /* Check if chip failed to wake up */ + if (REG_READ(ah, AR_CFG) == 0xdeadbeef) + return false; + if (AR_SREV_9300(ah)) return !ath9k_hw_detect_mac_hang(ah);