USB adapter firmware: 1.8.x generates lots of TX EXC events?

Chris Rankin rankincj
Sun Jun 12 00:44:30 PDT 2005

--- Jouni Malinen <jkmaline at> wrote:
> (More precisely, the hostap_sta_tx_exc_tasklet() function is invoked heavily
> when receiving frames from a 1.8.x USB adapter, and hardly ever when the adapter runs <= 1.7.6.)
> This would mean that the AP is not receiving acknowledgement frames from
> the client.
> > I remember that there is line of code in prism2_usb's hfa384x_drvr_txframe() function:
> > 
> >         txdesc.tx_control =
> >                 HFA384x_TX_MACPORT_SET(0) | HFA384x_TX_STRUCTYPE_SET(1) |
> >                 HFA384x_TX_TXEX_SET(0) | HFA384x_TX_TXOK_SET(0);
> > 
> > However, this says that we are already NOT transmitting either TXEX and TXOK frames. And IIRC,
> the
> > adapter will lock up if we do enable them. So can anyone explain what firmware 1.8.x might be
> > doing to trigger hostap's tx_exc tasklet, please?
> I'm not completely sure I understood what you are saying here. There are
> no "TXEX or TXOK frames" that the device would be sending. This is just
> letting the firmware now that prism2_usb does not want to receive TxExc
> or TxOk events. This is all internal to the client side and should not
> have anything to do with AP reporting TxExc events (no ack received).

Ah, OK. I guess I misunderstood that bit of the code, then. (I was just hoping that it was related
to what I was seeing ;-).) So does this mean that the creation of Ack frames is completely
controlled by the firmware?

> Either the client is not sending ack frames correctly or the AP is not
> receiving them.

Thanks for explaining that,

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