2010-10-30 16:35:30

by Vivek Natarajan

[permalink] [raw]
Subject: [PATCH] ath9k: Fix a DMA latency issue for Intel Pinetrail platforms.

Throughput was severely affected in Intel Pinetrail platforms
because of a DMA problem in C3 state. This patch fixes this
issue.

Signed-off-by: Vivek Natarajan <[email protected]>
CC: Johannes Berg <[email protected]>
---
drivers/net/wireless/ath/ath9k/ath9k.h | 1 +
drivers/net/wireless/ath/ath9k/init.c | 8 ++++++++
drivers/net/wireless/ath/ath9k/main.c | 5 +++++
3 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
index 973c919..04a9c86 100644
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -675,6 +675,7 @@ static inline void ath_read_cachesize(struct ath_common *common, int *csz)
}

extern struct ieee80211_ops ath9k_ops;
+extern struct pm_qos_request_list ath9k_pm_qos_req;
extern int modparam_nohwcrypt;
extern int led_blink;

diff --git a/drivers/net/wireless/ath/ath9k/init.c b/drivers/net/wireless/ath/ath9k/init.c
index 95b41db..6a0d99e 100644
--- a/drivers/net/wireless/ath/ath9k/init.c
+++ b/drivers/net/wireless/ath/ath9k/init.c
@@ -15,6 +15,7 @@
*/

#include <linux/slab.h>
+#include <linux/pm_qos_params.h>

#include "ath9k.h"

@@ -179,6 +180,8 @@ static const struct ath_ops ath9k_common_ops = {
.write = ath9k_iowrite32,
};

+struct pm_qos_request_list ath9k_pm_qos_req;
+
/**************************/
/* Initialization */
/**************************/
@@ -756,6 +759,9 @@ 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(&ath9k_pm_qos_req, PM_QOS_CPU_DMA_LATENCY,
+ PM_QOS_DEFAULT_VALUE);
+
return 0;

error_world:
@@ -811,6 +817,8 @@ void ath9k_deinit_device(struct ath_softc *sc)

ath9k_ps_wakeup(sc);

+ pm_qos_remove_request(&ath9k_pm_qos_req);
+
wiphy_rfkill_stop_polling(sc->hw->wiphy);
ath_deinit_leds(sc);

diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index c6ec800..81fa245 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -15,6 +15,7 @@
*/

#include <linux/nl80211.h>
+#include <linux/pm_qos_params.h>
#include "ath9k.h"
#include "btcoex.h"

@@ -1213,6 +1214,8 @@ static int ath9k_start(struct ieee80211_hw *hw)
ath9k_btcoex_timer_resume(sc);
}

+ pm_qos_update_request(&ath9k_pm_qos_req, 55);
+
mutex_unlock:
mutex_unlock(&sc->mutex);

@@ -1388,6 +1391,8 @@ static void ath9k_stop(struct ieee80211_hw *hw)

sc->sc_flags |= SC_OP_INVALID;

+ pm_qos_update_request(&ath9k_pm_qos_req, PM_QOS_DEFAULT_VALUE);
+
mutex_unlock(&sc->mutex);

ath_print(common, ATH_DBG_CONFIG, "Driver halt\n");
--
1.6.3.3