Re: [PATCH v2] cfg80211: Try multiple bandwidths when checking usable channels.

On Thu, 2014-07-24 at 14:43 +0200, Rostislav Lisovy wrote:

Current code checks if at least 20MHz bandwidth is allowed for
particular channel -- if it is not, the channel is disabled.
This disables usage of 5/10 MHz channels.
Another issue with the current code is that it may allow a channel
with bandwidth which is although less or the same as the "maximum
bandwidth allowed" but overlaps the border of the band.

The new approach is that there are multiple checks for one channel --
one for each bandwidth: 5, 10, 20, 40, 80, 160 MHz (when we hit a
bandwidth that is not allowed, greater bandwidths are automatically
disabled as well).  This prevents the following scenario to happen:
The 5 MHz bandwidth channel at the very end of the band is
successfully checked to fit which is followed by setting flags
IEEE80211_CHAN_NO_* according to the maximum bandwidth allowed by the
particular regulatory rule (which may be greater than the 5 MHz).
When someone will try to use that particular channel with the maximum
bandwidth allowed (e.g. 20 MHz), the resulting channel will not be in
the range of the band anymore (will overlap the border).

I really don't know what to do with this. I don't quite understand
what's going on, to be honest.

Luis?

johannes