[ath9k-devel] ath9k : Not able to set LongRetry and ShortRetry.

[Bhavesh Kamani <bhavesh.kamani@cyberoam.com>]

Hi Adrian,

Thanks a lot for the detailed info. I will try different combination in 
the pointed function and observe it.

Can you/someone help me what is the meaning of below macros?

#define INIT_SH_RETRY 10
#define INIT_LG_RETRY 10
#define INIT_SSH_RETRY 32
#define INIT_SLG_RETRY 32

Setting value 2 for all these macros, increases the packet drop by 
2%(approximately) in lower signal strength(approx -80 db), if I set the 
values to 64 then packet drop is very less.

Thanks,
Bhavesh.


On Monday 12 May 2014 10:00 PM, Adrian Chadd wrote:
> Hi,
>
> ath9k_11n_rate_series has "Tries". That's how many attempts at that
> given rate series entry.
>
> ar9002_set_txdesc() and ar9003_set_txdesc() (where the latter is
> relevant for you, using an ar9380) turn that rate series information
> into hardware specific information.
>
> ath_buf_set_rate() takes care of populating the bf->rates[] array,
> which is an array of ath9k_11n_rate_series entries. (Note - there's
> four of them. The hardware is limited to four.)
>
> Now, those fields in question behave slightly differently to what I
> think you expect:
>
> * Retry limits (D_RETRY_LIMIT)
>      Offset: 0x1080 + (D << 2)
>
>      3:0   - Frame RTS failure limit.  Specifies the number of times a
>              frame's RTS exchange may fail before the current transmission
>              series is terminated.  (A frame's RTS exchange fails if RTS is
>              enabled for the frame, but when the MAC sends the RTS on the
>              air, no CTS is received.)  Resets to 0x4.  Note: A value of 0x0
>              is UNSUPPORTED.
>      7:4   - Reserved
>      13:8  - Station RTS failure limit.  Specifies the number of times a
>              frame's RTS exchange may fail before the CW is reset to CW_MIN.
>              Resets to 0x20.  Note: A value of 0x0 is UNSUPPORTED.
>      19:14 - Station data failure limit.  Specifies the number of times a
>              frame's data exchange may fail before CW is reset to CW_MIN.
>              Resets to 0x20.  Note: A value of 0x0 is UNSUPPORTED.
>      31:20 - Reserved
>
> .. so frame RTS controls the RTS failure count; I think the rate
> series tries is the total attempts made to transmit the frame assuming
> RTS succeeds, and station RTS/station data have to do with contention
> window management.
>
> Hope that helps,
>
>
>
> -a
>
>
> On 12 May 2014 08:49, Bhavesh Kamani <bhavesh.kamani@cyberoam.com> wrote:
>> Hi Adrian,
>>
>> Can you please point me the exact file/function for rate schedule?
>>
>> But still I am not able to understand the usage of these macros.
>>
>> Thanks,
>> Bhavesh.
>>
>>
>> On Monday 12 May 2014 09:13 PM, Adrian Chadd wrote:
>>> There's also a maximum transmit retry counter in the rate schedule
>>> setup in the transmit descriptor.
>>>
>>> -a
>>>
>>>
>>> On 12 May 2014 07:59, Bhavesh Kamani <bhavesh.kamani@cyberoam.com> wrote:
>>>> Hi Team,
>>>>
>>>> I am using this Ar9380 NIC as AP using hostapd 2.0.
>>>>
>>>> Thanks,
>>>> Bhavesh.
>>>>
>>>> On Monday 12 May 2014 08:26 PM, Bhavesh Kamani wrote:
>>>>> Hi Team,
>>>>>
>>>>> I have changed the values of following four macros and set it to 2 to
>>>>> change LongRetryLimit and ShortRetryLimit, but I am not able to see
>>>>> any difference.
>>>>>
>>>>> File : drivers/net/wireless/ath/ath9k/mac.h
>>>>> #define INIT_SH_RETRY   10
>>>>> #define INIT_LG_RETRY   10
>>>>> #define INIT_SSH_RETRY  32
>>>>> #define INIT_SLG_RETRY  32
>>>>>
>>>>> After setting value 2, I am able to see more than 2 retries when ACK
>>>>> is not sent by WiFi client for particular packet.
>>>>> Please let me know how to change LongRetryLimit and ShortRetryLimit.
>>>>> Is it the right place where I am changing the values? If yes, then
>>>>> what are the possible value ranges for LongRetryLimit and
>>>>> ShortRetryLimit?
>>>>>
>>>>> ath9k version : backports-3.12.8-1
>>>>> Hardware : AR9380 miniPCIe
>>>>>
>>>>> Thanks,
>>>>> Bhavesh.
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>>