From: Mohammed Shafi Shajakhan <mshajakhan@xxxxxxxxxxx> The DMA latency issue is observed only in Intel pinetrail platforms but in the driver we had a default PM-QOS value of 55. This caused unnecessary power consumption and battery drain in other platforms. Address this issue by disabling PM-QOS by default by setting it's value as '0' and making code changes appropriately.This addresses the bug: https://bugzilla.kernel.org/show_bug.cgi?id=27532 If the user sees some DMA latency issue he can still use the pmqos as a module parameter to trade power for throughput as below: sudo modprobe ath9k pmqos=55 Signed-off-by: Mohammed Shafi Shajakhan <mshajakhan@xxxxxxxxxxx> --- drivers/net/wireless/ath/ath9k/ath9k.h | 4 +++- drivers/net/wireless/ath/ath9k/init.c | 9 +++++---- drivers/net/wireless/ath/ath9k/main.c | 9 +++++---- 3 files changed, 13 insertions(+), 9 deletions(-) diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h index 9272278..55fcd01 100644 --- a/drivers/net/wireless/ath/ath9k/ath9k.h +++ b/drivers/net/wireless/ath/ath9k/ath9k.h @@ -57,7 +57,9 @@ struct ath_node; #define A_MAX(a, b) ((a) > (b) ? (a) : (b)) -#define ATH9K_PM_QOS_DEFAULT_VALUE 55 +/* By default PM QOS is disabled */ +#define ATH9K_PM_QOS_DEFAULT_VALUE 0 + #define TSF_TO_TU(_h,_l) \ ((((u32)(_h)) << 22) | (((u32)(_l)) >> 10)) diff --git a/drivers/net/wireless/ath/ath9k/init.c b/drivers/net/wireless/ath/ath9k/init.c index e5c1eea..658ea02 100644 --- a/drivers/net/wireless/ath/ath9k/init.c +++ b/drivers/net/wireless/ath/ath9k/init.c @@ -43,7 +43,7 @@ MODULE_PARM_DESC(btcoex_enable, "Enable wifi-BT coexistence"); int ath9k_pm_qos_value = ATH9K_PM_QOS_DEFAULT_VALUE; module_param_named(pmqos, ath9k_pm_qos_value, int, S_IRUSR | S_IRGRP | S_IROTH); -MODULE_PARM_DESC(pmqos, "User specified PM-QOS value"); +MODULE_PARM_DESC(pmqos, "User specified PM-QOS value, by default disabled"); bool is_ath9k_unloaded; /* We use the hw_value as an index into our private channel structure */ @@ -759,8 +759,8 @@ int ath9k_init_device(u16 devid, struct ath_softc *sc, u16 subsysid, ath_init_leds(sc); ath_start_rfkill_poll(sc); - - pm_qos_add_request(&sc->pm_qos_req, PM_QOS_CPU_DMA_LATENCY, + if (ath9k_pm_qos_value) + pm_qos_add_request(&sc->pm_qos_req, PM_QOS_CPU_DMA_LATENCY, PM_QOS_DEFAULT_VALUE); return 0; @@ -819,7 +819,8 @@ void ath9k_deinit_device(struct ath_softc *sc) ath9k_ps_restore(sc); ieee80211_unregister_hw(hw); - pm_qos_remove_request(&sc->pm_qos_req); + if (ath9k_pm_qos_value) + pm_qos_remove_request(&sc->pm_qos_req); ath_rx_cleanup(sc); ath_tx_cleanup(sc); ath9k_deinit_softc(sc); diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c index 4ed43b2..3855092 100644 --- a/drivers/net/wireless/ath/ath9k/main.c +++ b/drivers/net/wireless/ath/ath9k/main.c @@ -1119,9 +1119,10 @@ static int ath9k_start(struct ieee80211_hw *hw) /* User has the option to provide pm-qos value as a module * parameter rather than using the default value of - * 'ATH9K_PM_QOS_DEFAULT_VALUE'. + * 'ATH9K_PM_QOS_DEFAULT_VALUE' which disables PM QOS. */ - pm_qos_update_request(&sc->pm_qos_req, ath9k_pm_qos_value); + if (ath9k_pm_qos_value) + pm_qos_update_request(&sc->pm_qos_req, ath9k_pm_qos_value); if (ah->caps.pcie_lcr_extsync_en && common->bus_ops->extn_synch_en) common->bus_ops->extn_synch_en(common); @@ -1266,8 +1267,8 @@ static void ath9k_stop(struct ieee80211_hw *hw) ath_radio_disable(sc, hw); sc->sc_flags |= SC_OP_INVALID; - - pm_qos_update_request(&sc->pm_qos_req, PM_QOS_DEFAULT_VALUE); + if (ath9k_pm_qos_value) + pm_qos_update_request(&sc->pm_qos_req, PM_QOS_DEFAULT_VALUE); mutex_unlock(&sc->mutex); -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
