Re: [RFC] ath9k: Fix ath9k prevents CPU to enter C3 states

From: Mohammed Shafi <mshajakhan@atheros.com>
To: "John W. Linville" <linville@tuxdriver.com>
Cc: Mohammed Shajakhan <Mohammed.Shajakhan@Atheros.com>,
	"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
	Luis Rodriguez <Luis.Rodriguez@Atheros.com>,
	"stable@kernel.org" <stable@kernel.org>
Subject: Re: [RFC] ath9k: Fix ath9k prevents CPU to enter C3 states
Date: Fri, 4 Mar 2011 19:56:53 +0530	[thread overview]
Message-ID: <4D70F6AD.7050700@atheros.com> (raw)
In-Reply-To: <20110304133722.GA9866@tuxdriver.com>

On Friday 04 March 2011 07:07 PM, John W. Linville wrote:
> On Fri, Mar 04, 2011 at 11:36:37AM +0530, Mohammed Shafi wrote:
>    
>> On Wednesday 16 February 2011 10:35 AM, Mohammed Shafi wrote:
>>      
>>> On Tuesday 15 February 2011 09:42 PM, John W. Linville wrote:
>>>        
>>>> Despite the [RFC], I am applying this.  I should have reverted all
>>>> of this three weeks ago...
>>>>          
>> John can you please push this to stable kernel ?
>>      
> Stable folks, this is the commit in Linus's tree;
>    
Thanks a lot John.
> commit 0f5cd45960173ba5b36727decbb4a241cbd35ef9
> Author: Mohammed Shafi Shajakhan<mshajakhan@atheros.com>
> Date:   Tue Feb 15 21:29:32 2011 +0530
>
>      ath9k: Fix ath9k prevents CPU to enter C3 states
>
>      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.
>
>      Remove the pm-qos thing in the driver code and address the throughput
>      issue in Intel pinetrail platfroms in user space using any one of
>      the scripts in below links:
>
>      http://www.kernel.org/pub/linux/kernel/people/mcgrof/scripts/cpudmalatency.c
>      http://johannes.sipsolutions.net/files/netlatency.c.txt
>
>      More details can be found in the following bugzilla link:
>
>      https://bugzilla.kernel.org/show_bug.cgi?id=27532
>
>      This reverts the following commits:
>
>          98c316e348bedffa730e6f1e4baeb8a3c3e0f28b
>          4dc3530df7c0428b41c00399a7ee8c929406d181
>          10598c124ecabbbfd7522f74de19b8f7d52a1bee
>
>      Signed-off-by: Mohammed Shafi Shajakhan<mshajakhan@atheros.com>
>      Signed-off-by: John W. Linville<linville@tuxdriver.com>
>
>    
>>> Thanks John.
>>>        
>>>> John
>>>>
>>>> On Tue, Feb 15, 2011 at 09:29:32PM +0530, Mohammed Shafi
>>>> Shajakhan wrote:
>>>>          
>>>>> From: Mohammed Shafi Shajakhan<mshajakhan@atheros.com>
>>>>>
>>>>> 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.
>>>>>     Remove the pm-qos thing in the driver code and address the
>>>>> throughput issue in
>>>>> Intel pinetrail platfroms in user space using any one of the
>>>>> scripts in below links:
>>>>> http://www.kernel.org/pub/linux/kernel/people/mcgrof/scripts/cpudmalatency.c
>>>>>
>>>>> http://johannes.sipsolutions.net/files/netlatency.c.txt
>>>>> More details can be found in the following bugzilla link:
>>>>> https://bugzilla.kernel.org/show_bug.cgi?id=27532
>>>>>
>>>>> Signed-off-by: Mohammed Shafi Shajakhan<mshajakhan@atheros.com>
>>>>> ---
>>>>>   drivers/net/wireless/ath/ath9k/ath9k.h |    5 -----
>>>>>   drivers/net/wireless/ath/ath9k/init.c  |    7 -------
>>>>>   drivers/net/wireless/ath/ath9k/main.c  |    8 --------
>>>>>   3 files changed, 0 insertions(+), 20 deletions(-)
>>>>>
>>>>> diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h
>>>>> b/drivers/net/wireless/ath/ath9k/ath9k.h
>>>>> index ba436cd..0052f64 100644
>>>>> --- a/drivers/net/wireless/ath/ath9k/ath9k.h
>>>>> +++ b/drivers/net/wireless/ath/ath9k/ath9k.h
>>>>> @@ -21,7 +21,6 @@
>>>>>   #include<linux/device.h>
>>>>>   #include<linux/leds.h>
>>>>>   #include<linux/completion.h>
>>>>> -#include<linux/pm_qos_params.h>
>>>>>
>>>>>   #include "debug.h"
>>>>>   #include "common.h"
>>>>> @@ -57,8 +56,6 @@ struct ath_node;
>>>>>
>>>>>   #define A_MAX(a, b) ((a)>   (b) ? (a) : (b))
>>>>>
>>>>> -#define ATH9K_PM_QOS_DEFAULT_VALUE    55
>>>>> -
>>>>>   #define TSF_TO_TU(_h,_l) \
>>>>>       ((((u32)(_h))<<   22) | (((u32)(_l))>>   10))
>>>>>
>>>>> @@ -650,7 +647,6 @@ struct ath_softc {
>>>>>
>>>>>       struct ath_ant_comb ant_comb;
>>>>>
>>>>> -    struct pm_qos_request_list pm_qos_req;
>>>>>   };
>>>>>
>>>>>   void ath9k_tasklet(unsigned long data);
>>>>> @@ -665,7 +661,6 @@ static inline void
>>>>> ath_read_cachesize(struct ath_common *common, int *csz)
>>>>>   extern struct ieee80211_ops ath9k_ops;
>>>>>   extern int ath9k_modparam_nohwcrypt;
>>>>>   extern int led_blink;
>>>>> -extern int ath9k_pm_qos_value;
>>>>>   extern bool is_ath9k_unloaded;
>>>>>
>>>>>   irqreturn_t ath_isr(int irq, void *dev);
>>>>> diff --git a/drivers/net/wireless/ath/ath9k/init.c
>>>>> b/drivers/net/wireless/ath/ath9k/init.c
>>>>> index e5c1eea..8fed4e4 100644
>>>>> --- a/drivers/net/wireless/ath/ath9k/init.c
>>>>> +++ b/drivers/net/wireless/ath/ath9k/init.c
>>>>> @@ -41,9 +41,6 @@ static int ath9k_btcoex_enable;
>>>>>   module_param_named(btcoex_enable, ath9k_btcoex_enable, int, 0444);
>>>>>   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");
>>>>>
>>>>>   bool is_ath9k_unloaded;
>>>>>   /* We use the hw_value as an index into our private channel
>>>>> structure */
>>>>> @@ -760,9 +757,6 @@ 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,
>>>>> -               PM_QOS_DEFAULT_VALUE);
>>>>> -
>>>>>       return 0;
>>>>>
>>>>>   error_world:
>>>>> @@ -819,7 +813,6 @@ void ath9k_deinit_device(struct ath_softc *sc)
>>>>>       ath9k_ps_restore(sc);
>>>>>
>>>>>       ieee80211_unregister_hw(hw);
>>>>> -    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 4f568b8..1d2c7c3 100644
>>>>> --- a/drivers/net/wireless/ath/ath9k/main.c
>>>>> +++ b/drivers/net/wireless/ath/ath9k/main.c
>>>>> @@ -1117,12 +1117,6 @@ static int ath9k_start(struct ieee80211_hw *hw)
>>>>>               ath9k_btcoex_timer_resume(sc);
>>>>>       }
>>>>>
>>>>> -    /* 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'.
>>>>> -     */
>>>>> -    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);
>>>>>
>>>>> @@ -1267,8 +1261,6 @@ static void ath9k_stop(struct ieee80211_hw *hw)
>>>>>
>>>>>       sc->sc_flags |= SC_OP_INVALID;
>>>>>
>>>>> -    pm_qos_update_request(&sc->pm_qos_req, PM_QOS_DEFAULT_VALUE);
>>>>> -
>>>>>       mutex_unlock(&sc->mutex);
>>>>>
>>>>>       ath_dbg(common, ATH_DBG_CONFIG, "Driver halt\n");
>>>>> -- 
>>>>> 1.7.0.4
>>>>>
>>>>>
>>>>>            
>> --
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>>      
>