Complexity of Adding 5/10 MHz Channel Support

Complexity of Adding 5/10 MHz Channel Support

[Galen]

Can anybody give me an idea the extent and complexity of adding support for 5/10 MHz channels in mac80211?

Several different radios (including those supported by ath5k and ath9k) have the hardware capability to operate at 5 MHz. Obviously, support in those drivers is a separate issue, but it is my understanding that mac80211 must first support 5/10 MHz channels.

Thoughts would be appreciated.

-Galen

Re: Complexity of Adding 5/10 MHz Channel Support

[Johannes Berg]

On Fri, 2010-10-15 at 15:30 -0700, Galen wrote:
> Can anybody give me an idea the extent and complexity of adding
> support for 5/10 MHz channels in mac80211?
> 
> Several different radios (including those supported by ath5k and
> ath9k) have the hardware capability to operate at 5 MHz. Obviously,
> support in those drivers is a separate issue, but it is my
> understanding that mac80211 must first support 5/10 MHz channels.

Since we already have channel types, I've always suggested to add 5/10
as such. The complexity comes from the fact that some channel types are
incompatible, and we currently do not have to handle that -- a regular
scan for example will cover all current channel types, but with 5/10 MHz
you need to do special scans etc.

Also, you need to start in cfg80211, not mac80211, and make everything
from auth/assoc/connect/ibss-join etc. aware of channel types as well as
center freq.

johannes

Re: Complexity of Adding 5/10 MHz Channel Support

[Ricardo]

Johannes Berg <johannes@...> writes:

> 
> On Fri, 2010-10-15 at 15:30 -0700, Galen wrote:
> > Can anybody give me an idea the extent and complexity of adding
> > support for 5/10 MHz channels in mac80211?
> > 
> > Several different radios (including those supported by ath5k and
> > ath9k) have the hardware capability to operate at 5 MHz. Obviously,
> > support in those drivers is a separate issue, but it is my
> > understanding that mac80211 must first support 5/10 MHz channels.
> 
> Since we already have channel types, I've always suggested to add 5/10
> as such. The complexity comes from the fact that some channel types are
> incompatible, and we currently do not have to handle that -- a regular
> scan for example will cover all current channel types, but with 5/10 MHz
> you need to do special scans etc.
> 
> Also, you need to start in cfg80211, not mac80211, and make everything
> from auth/assoc/connect/ibss-join etc. aware of channel types as well as
> center freq.
> 
> johannes
> 
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> 

Hello,

I am also interested in seeing/having this functionality implemented in ath5k. I 
am not an expert or have a big knowledge of the driver itself but it would be 
great to be able to change the channel width (even if it was a "dirty" solution, 
like manually hardcode some register values to achieve the desired channel 
widths).

Maybe someone has any useful tips for me? I can do the "dirty work" but i just 
need some indications on HOW to do it.

Best regards
Ricardo