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Re: [PATCH/RFC] ath9k: fix two more bugs in tx power

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On Fri, May 27, 2011 at 1:16 PM, Adrian Chadd <adrian@xxxxxxxxxxx> wrote:
> That should only really hit 0 if you're configuring a low TX power level.. ?

true.

>
> Hm, I spy with my little eye a small bug with the eeprom power
> handling for the v14 eeprom.
> The modal header has:
>
>        u8 pwrDecreaseFor2Chain;
>        u8 pwrDecreaseFor3Chain;
>
> but the EEPROM code is hard-coded to use -6 for 2-chain reduction and
> -9 for 3-chain reduction.

yes, but I am not sure whether this configuration from eeprom is
needed for AR9003?
if they are hardcoding the data from eeprom may return 0 ?

>
> A completely untested patch (but FreeBSD does this) :
>
> diff --git a/drivers/net/wireless/ath/ath9k/eeprom_def.c
> b/drivers/net/wireless/ath/ath9k/eeprom_def.c
> index 17f0a68..09f587b 100644
> --- a/drivers/net/wireless/ath/ath9k/eeprom_def.c
> +++ b/drivers/net/wireless/ath/ath9k/eeprom_def.c
> @@ -906,6 +906,7 @@ static void
> ath9k_hw_set_def_power_per_rate_table(struct ath_hw *ah,
>        struct chan_centers centers;
>        int tx_chainmask;
>        u16 twiceMinEdgePower;
> +       u8 pwrDecreaseFor2Chain, pwrDecreaseFor3Chain;
>
>        tx_chainmask = ah->txchainmask;
>
> @@ -924,6 +925,11 @@ static void
> ath9k_hw_set_def_power_per_rate_table(struct ath_hw *ah,
>        twiceLargestAntenna = (int16_t)min(AntennaReduction -
>                                           twiceLargestAntenna, 0);
>
> +       pwrDecreaseFor2Chain = pEepData->modalHeader
> +                                 [IS_CHAN_2GHZ(chan)].pwrDecreaseFor2Chain;
> +       pwrDecreaseFor3Chain = pEepData->modalHeader
> +                                 [IS_CHAN_2GHZ(chan)].pwrDecreaseFor3Chain;
> +
>        maxRegAllowedPower = twiceMaxRegulatoryPower + twiceLargestAntenna;
>
>        if (regulatory->tp_scale != ATH9K_TP_SCALE_MAX) {
> @@ -937,14 +943,14 @@ static void
> ath9k_hw_set_def_power_per_rate_table(struct ath_hw *ah,
>        case 1:
>                break;
>        case 2:
> -               if (scaledPower > REDUCE_SCALED_POWER_BY_TWO_CHAIN)
> -                       scaledPower -= REDUCE_SCALED_POWER_BY_TWO_CHAIN;
> +               if (scaledPower > pwrDecreaseFor2Chain)
> +                       scaledPower -= pwrDecreaseFor2Chain;
>                else
>                        scaledPower = 0;
>                break;
>        case 3:
> -               if (scaledPower > REDUCE_SCALED_POWER_BY_THREE_CHAIN)
> -                       scaledPower -= REDUCE_SCALED_POWER_BY_THREE_CHAIN;
> +               if (scaledPower > pwrDecreaseFor3Chain)
> +                       scaledPower -= pwrDecreaseFor3Chain;
>                else
>                        scaledPower = 0;
>                break;
>

hmmm in ath9k not exactly the same is there,
   REG_WRITE(ah, AR_PHY_POWER_TX_SUB,
                  ATH9K_POW_SM(pModal->pwrDecreaseFor3Chain, 6)
                  | ATH9K_POW_SM(pModal->pwrDecreaseFor2Chain, 0));



>
> On 27 May 2011 15:18, Mohammed Shafi <shafi.wireless@xxxxxxxxx> wrote:
>> On Thu, May 26, 2011 at 10:13 PM, Daniel Halperin
>> <dhalperi@xxxxxxxxxxxxxxxxx> wrote:
>>> This is the same fix as
>>>
>>>    commit 841051602e3fa18ea468fe5a177aa92b6eb44b56
>>>    Author: Matteo Croce <technoboy85@xxxxxxxxx>
>>>    Date:   Fri Dec 3 02:25:08 2010 +0100
>>>
>>>    The ath9k driver subtracts 3 dBm to the txpower as with two radios the
>>>    signal power is doubled.
>>>    The resulting value is assigned in an u16 which overflows and makes
>>>    the card work at full power.
>>>
>>> in two more places. I grepped the ath tree and didn't find any others.
>>>
>>> Cc: stable@xxxxxxxxxx
>>> Signed-off-by: Daniel Halperin <dhalperi@xxxxxxxxxxxxxxxxx>
>>> ---
>>> RFC: Blaise Gassend actually pointed these two bugs out on 12/7/2010 but no
>>> one fixed. There was some discussion about refactoring/improving this code,
>>> but it never seemed to get anywhere. See this thread:
>>>
>>>    http://comments.gmane.org/gmane.linux.drivers.ath9k.devel/4601
>>> ---
>>>  drivers/net/wireless/ath/ath9k/ar9003_eeprom.c |   10 ++++++++--
>>>  drivers/net/wireless/ath/ath9k/eeprom_9287.c   |   10 ++++++++--
>>>  2 files changed, 16 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/net/wireless/ath/ath9k/ar9003_eeprom.c b/drivers/net/wireless/ath/ath9k/ar9003_eeprom.c
>>> index 729534c..934e419 100644
>>> --- a/drivers/net/wireless/ath/ath9k/ar9003_eeprom.c
>>> +++ b/drivers/net/wireless/ath/ath9k/ar9003_eeprom.c
>>> @@ -4645,10 +4645,16 @@ static void ar9003_hw_set_power_per_rate_table(struct ath_hw *ah,
>>>        case 1:
>>>                break;
>>>        case 2:
>>> -               scaledPower -= REDUCE_SCALED_POWER_BY_TWO_CHAIN;
>>> +               if (scaledPower > REDUCE_SCALED_POWER_BY_TWO_CHAIN)
>>> +                       scaledPower -= REDUCE_SCALED_POWER_BY_TWO_CHAIN;
>>> +               else
>>> +                       scaledPower = 0;
>>
>> should we make the scaledPower as '0' lets have the first check if it
>> fails, let us retain the  scaledPower obtained by
>>  scaledPower = min(powerLimit, maxRegAllowedPower);
>>
>> am I missing something ?
>> making scaledPower affects this
>>   minCtlPower = (u8)min(twiceMaxEdgePower, scaledPower);
>>
>> which in turn affects
>>  pPwrArray[i] =
>>                                          (u8)min((u16)pPwrArray[i],
>>                                                  minCtlPower);
>>
>> which in turn affects target Power values
>>
>>
>>
>>
>>
>>>                break;
>>>        case 3:
>>> -               scaledPower -= REDUCE_SCALED_POWER_BY_THREE_CHAIN;
>>> +               if (scaledPower > REDUCE_SCALED_POWER_BY_THREE_CHAIN)
>>> +                       scaledPower -= REDUCE_SCALED_POWER_BY_THREE_CHAIN;
>>> +               else
>>> +                       scaledPower = 0;
>>>                break;
>>>        }
>>>
>>> diff --git a/drivers/net/wireless/ath/ath9k/eeprom_9287.c b/drivers/net/wireless/ath/ath9k/eeprom_9287.c
>>> index 7856f0d..343fc9f 100644
>>> --- a/drivers/net/wireless/ath/ath9k/eeprom_9287.c
>>> +++ b/drivers/net/wireless/ath/ath9k/eeprom_9287.c
>>> @@ -524,10 +524,16 @@ static void ath9k_hw_set_ar9287_power_per_rate_table(struct ath_hw *ah,
>>>        case 1:
>>>                break;
>>>        case 2:
>>> -               scaledPower -= REDUCE_SCALED_POWER_BY_TWO_CHAIN;
>>> +               if (scaledPower > REDUCE_SCALED_POWER_BY_TWO_CHAIN)
>>> +                       scaledPower -= REDUCE_SCALED_POWER_BY_TWO_CHAIN;
>>> +               else
>>> +                       scaledPower = 0;
>>>                break;
>>>        case 3:
>>> -               scaledPower -= REDUCE_SCALED_POWER_BY_THREE_CHAIN;
>>> +               if (scaledPower > REDUCE_SCALED_POWER_BY_THREE_CHAIN)
>>> +                       scaledPower -= REDUCE_SCALED_POWER_BY_THREE_CHAIN;
>>> +               else
>>> +                       scaledPower = 0;
>>>                break;
>>>        }
>>>        scaledPower = max((u16)0, scaledPower);
>>> --
>>> 1.7.0.4
>>>
>>>
>>> --
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>>>
>>
>>
>>
>> --
>> shafi
>>
>



-- 
shafi
--
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