Re: [Madwifi-devel] [PATCH] RFC: link distance specification

[Sam L. <sa...@er...>]

On Wednesday 26 May 2004 01:53 am, Michael Renzmann wrote:
> Hi all.
>
> Another patch for review.
>
>
> Introduction
> ============
> Attached is a patch that allows to specify the link distance (either by
> using a parameter at module loadtime or by using sysctl at runtime).
> Slottime, ACK- and CTS-timeouts will be adjusted whenever the link
> distance is set/changed.

If you can set a value w/ a sysctl then I see no reason for a module parameter 
unless it is important to have the value set before the interface is attached 
(e.g. debugging or the country code).  You should be able to get the same 
effect by doing the sysctl in a hotplug script or similar.

>
> The patch is based on the work recently posted as patch to madwifi-users
> by Togg. He ported the sysctl-interface code from WPA to HEAD, which
> basically allows to modify slottime, ack-timeout and cts-timeout.
>
> I added support for another sysctl (for setting distance), the module
> parameter "distance" and automatic calculation of the timings depending
> on link distance.

Algorithmic conversion of parameters belongs in user-mode applications and not 
the driver unless they are the "one true way" to specify a value or there are 
synchronization issues such as needing to update multiple values together to 
avoid having the hardware in a bad state.  It's not clear to me that this 
stuff qualifies. I also suspect there are better solutions for tuning the 
timeout values than using a fixed formula; e.g. by sending "echo packets" and 
monitoring the TSF to get proper timing.

>
> Note: Togg mentioned that the manual settings will be lost with his
> patch, as soon as the card is reset (or looses association). I think I
> have fixed this problem, by adding a call to ath_settimings() inside
> ath_init().

I've fixed the HAL to save+restore these register settings across a reset.  It 
should be in the next release.

<...other stuff deleted...>

	Sam