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Ticket #2292 (new defect)

Opened 13 years ago

Last modified 12 years ago

cwmin and cwmax max value

Reported by: Assigned to:
Priority: major Milestone:
Component: madwifi: driver Version: v0.9.4
Keywords: wmm cwmin cwmax Cc:
Patch is attached: 0 Pending: 0


I'm using newest madwifi from Debian repositories. I can't set cwmin and cwmax to value bigger then 15. This waht I get: # iwpriv ath0 cwmax 0 0 1023 Interface doesn't accept private ioctl.... cwmax (8BE4): Invalid argument

Change History

(follow-up: ↓ 2 ) 05/31/09 18:14:16 changed by anonymous

I think 15 is the max value you can set

(in reply to: ↑ 1 ) 07/23/09 05:14:05 changed by anonymous

Replying to anonymous:

I think 15 is the max value you can set

This is a real question. Either the documentation is wrong, or the implementation is wrong or perhaps both. The standard allows cwmin and cwmax to range between 0 and 32767, but is (usually?) calculated from ecwmin and ecwmax where

cwmin = 2ecwmin-1 and cwmax = 2ecwmax-1. See the IEEE doc for 802.1e, pg 49.

Ok so if the command above actually manipulates ecwmin and ecwmax, then cwmin and cwmax will have the acceptable ranges. It's misleading, though, to document that cwmin and cwmax are being set. This is assuming, of course, that cwmin and cwmax are subsequently being set to what the doc calls for for example one implementation

cwmin = (1 << ecwmin) - 1;

Furthermore, it is ecwmin and ecwmax that are transmitted by the AP QOS information Becon, (4 bits each) pp 47-48.

So (and I'm really guessing here), it's really ecwmin and ecwmax that are being set by the above command and the documentation should be changed.