Re: [PATCH] ath5k: Set ACK to user lower bit rates

["Nick Kossifidis" <mickflemm@gmail.com>]

2007/11/2, Nick Kossifidis <mickflemm@gmail.com>:
> 2007/11/2, Luis R. Rodriguez <mcgrof@gmail.com>:
> > Sorry, forgot this last hunk in my patch series... This applies on top
> > of my series.
> >
> > This sets the ACK bitrate to the lower rates. Without this I get
> > about 70% packet loss when using the 11M rate. Not sure exactly what rates
> > this is setting the HW to send the ACKs in but it sure does help.
> >
>
> 6Mbits for OFDM (have checked it out with various sniffers), if not
> set i usualy get 24Mbits for acks when transmiting on 54Mbit.
>
> Haven't checked it for CCK but i guess it's 1 or 2 Mbits, have a look
> at my comments inside reg.h...
>
> #define AR5K_STA_ID1_ACKCTS_6MB         0x01000000      /* Use 6Mbit/s
> for ACK/CTS (?) */
> #define AR5K_STA_ID1_BASE_RATE_11B      0x02000000      /* Use 11b
> base rate (for ACK/CTS ?) [5211+] */
>

Also note that setting these bits is safe and cause a more stable
behaviour. If these bits are not set then control_rate is being used
(check out rate tables -remember these tables are hardcoded in hal,
that's why they have put control_rate there, to let us know what rate
is being used for ack/cts frames by hw-).

Here it is...
(transmision rate) -> (ack/cts rate)

OFDM
6 - 12 -> 6
12 - 24 -> 12
24 - 54 -> 24

CCK
1 - 2 -> 1
2 - 11 -> 2

So it still doesn't make sense that you had 70% loss, i mean any rate
between 2 and 11Mbits would cause the same ack rate (2Mbits), even if
you didn't set that bit.

-- 
GPG ID: 0xD21DB2DB
As you read this post global entropy rises. Have Fun ;-)
Nick