Re: tx_status reporting of RTS/CTS frames

[Ivo van Doorn <ivdoorn@gmail.com>]

On Thursday 13 December 2007, Mattias Nissler wrote:
> 
> On Thu, 2007-12-13 at 12:34 +0100, Johannes Berg wrote:
> > > rt2x00 devices have some flags in the TX descriptor that basically tell
> > > the device to send a burst of frames, optionally requesting to wait for
> > > an ack (i.e. CTS in the case of an RTS frame) for any of them.
> > 
> > Interesting. I can't the place where that is set though, can you point
> > me to it?
> 
> For each frame, rt2x00 creates a txdata_entry_desc structure (see
> rt2x00lib_write_tx_desc()), which holds all the information that is
> written to the actual tx descriptors (format of these varies among the
> different devices we support, but the information in the tx descriptors
> is roughly the same). See rt61pci_write_tx_desc() for an example of how
> the information is stored into the actual tx descriptor, but that's
> rather boring.
> 
> The bits you're interested in are ENTRY_TXD_ACK and ENTRY_TXD_BURST.
> BURST tells the device the next frame is part of the same burst (also
> note that we have to set the correct IFS), i.e. the next frame goes out
> directly after the current one (respecting the IFS of course). The
> TXD_ACK bit means the hardware should wait for an ack of some kind (e.g.
> CTS for RTS frames).

Additionally there is the ENTRY_TXD_RTS_FRAME flag to indicate the frame
is a rts frame. This is something that at least rt2400pci and rt2500pci required
for rts frames in the TX queue.

Ivo