Re: [bcmdhd] Retransmission packet

["Arend van Spriel" <arend@broadcom.com>]

+ linux-wireless

On 06/05/2013 02:04 PM, Matteo wrote:
> Hi Arend,
> thank a lot.
>
> yea, I wanted to find the retransmissions of the frame over the air.
> I don't know, if other devices (broadcom or atheros) could give that information.

On Android? I guess any mac80211 based driver could give you that 
information. The information is provided by the driver to mac80211 upon 
txstatus using struct ieee80211_tx_info::status. The rates field should 
contain the rates at which the transmits were attempted and how often 
(see explanation of struct ieee80211_tx_rate).

Regards,
Arend

> Thanks again
> Matteo
>
> On Jun 5, 2013, at 10:50 AM, "Arend van Spriel" <arend@broadcom.com> wrote:
>
>> - linux-wireless@vger.kernel.org
>>
>> bcmdhd is not an upstream linux driver so removing that mailing list address.
>>
>> On 06/04/2013 11:20 PM, Matteo Danieletto wrote:
>>> Hi all,
>>>
>>> I am trying to extract the number of retransmissions frame occur during
>>> data transfer between two nodes.
>>
>> I suppose you want the know the retransmissions of the frame over the air. The retries in the code below are over the bus between host and device. So that is not the information you want (right?).
>>
>> The bad news is that the information is not available in the driver.
>>
>> Regards,
>> Arend
>>
>>> I found in did_sdio.c this function:
>>>
>>> 1. /* Writes a HW/SW header into the packet and sends it. */
>>> 2. /* Assumes: (a) header space already there, (b) caller holds lock */
>>> 3. staticint
>>> 4. dhdsdio_txpkt(dhd_bus_t *bus,void*pkt,uint chan,boolfree_pkt)
>>>
>>>
>>> .
>>> .
>>> .
>>> there is this part:
>>>
>>> 1. do{
>>> 2.                  ret
>>>     =dhd_bcmsdh_send_buf(bus,bcmsdh_cur_sbwad(sdh),SDIO_FUNC_2,F2SYNC,
>>> 3.                                            frame,len,pkt,NULL,NULL);
>>> 4.                  bus->f2txdata++;
>>> 5.                  ASSERT(ret !=BCME_PENDING);
>>> 6.
>>>
>>> 7. if(ret <0){
>>> 8. /* On failure, abort the command and terminate the frame */
>>> 9.                          DHD_INFO(("%s: sdio error %d, abort command
>>>     and terminate frame.\n",
>>> 10.                                    __FUNCTION__,ret));
>>> 11.                          bus->tx_sderrs++;
>>> 12.
>>>
>>> 13.                          bcmsdh_abort(sdh,SDIO_FUNC_2);
>>> 14.
>>>     bcmsdh_cfg_write(sdh,SDIO_FUNC_1,SBSDIO_FUNC1_FRAMECTRL,
>>> 15.                                           SFC_WF_TERM,NULL);
>>> 16.                          bus->f1regdata++;
>>> 17.
>>>
>>> 18. for(i =0;i <3;i++){
>>> 19.                                  uint8 hi,lo;
>>> 20.                                  hi =bcmsdh_cfg_read(sdh,SDIO_FUNC_1,
>>> 21.
>>>       SBSDIO_FUNC1_WFRAMEBCHI,NULL);
>>> 22.                                  lo =bcmsdh_cfg_read(sdh,SDIO_FUNC_1,
>>> 23.
>>>       SBSDIO_FUNC1_WFRAMEBCLO,NULL);
>>> 24.                                  bus->f1regdata +=2;
>>> 25. if((hi ==0)&&(lo ==0))
>>> 26. break;
>>> 27. }
>>> 28.
>>>
>>> 29. }
>>> 30. if(ret ==0){
>>> 31.                          bus->tx_seq =(bus->tx_seq
>>>     +1)%SDPCM_SEQUENCE_WRAP;
>>> 32. }
>>> 33. }while((ret <0)&&retrydata &&retries++<TXRETRIES);
>>>
>>>
>>>
>>> I exploited iperf to create a data stream between two nodes, but it
>>> never occurred an incrementation of retries variable, then everytime
>>> did_bcmsdh_send_buf returned 0.
>>>
>>> So, I don't know if it is the right point to extract this information
>>> and it never occurred a retransmission, or more it is not possible
>>> extract what I want.
>>>
>>> Thanks a lot
>>>
>>> Matteo
>>>
>>>
>>
>>
>
>