Thread (8 messages) 8 messages, 5 authors, 2005-01-27

Re: Where Linux 802.11x support needs work

From: Roar Bjørgum Rotvik <hidden>
Date: 2005-01-26 07:31:35

Michael Wu wrote:
On Tuesday 25 January 2005 11:03 pm, Dan Williams wrote:
quoted
quoted
One of the big item not mentionned by you is the in-kernel
802.11 stack (native frames and management). If done right, I guess it
would mostly be transparent to you...
You know, I was thinking of it and I just forgot to put it on the list.
If you're including madwifi and ipw2x00, we have a grand total of what, 3
or 4 802.11 stacks in the kernel at the same time?  (madwifi,
orinoco/hermes, ipw2x00, linux-wlan-ng)
Only orinoco/hermes is in the kernel, and that doesn't really have much of an 
802.11 stack, since most things are done in hardware. Madwifi has a fairly 
complete 802.11 stack (ported from netbsd), and so does adm8211. Dunno about 
ipw2x00.
Do any of these 80.11 stacks (or the upstream linux network stack) have 
a solution for WLAN cards with 802.11e (QoS extension) with more than 
one HW/firmware transmit queues?

As you may or may not know WLAN cards implementing 802.11e may have more 
than one HW/firmware transmit queue (I know of an 802.11a chip with 
802.11e extension that have 4 transmit queues in hardware/firmware with 
different priority).

As far as I know the linux network stack today only have one qdisc queue 
pr. device (struct netdev), so the driver may only stop/start 
(netif_stop_queue()/netif_wake_queue()) one queue at a time. This is a 
problem for drivers with more than one HW/firmware transmit queues, as 
you can not let a full low priority HW queue block the netdev queue.

Is there an existing solution for this problem, or is an 
multiqueue-pr-device solution being planned as part of introducing a 
common 802.11 stack in the kernel?

-- 
Roar B. Rotvik
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