[PATCH] hw_features: provide proper fallback to HT20 by defering channel pair check

Jouni Malinen j at w1.fi
Sat Apr 1 01:57:48 PDT 2017

On Wed, Mar 29, 2017 at 02:04:27PM +0200, Eduardo Abinader wrote:
> Defer decision, so we could possibly benefit from a fallback.
> For instance, that may happen with FCC UNII ch165,
> which is 20 MHz wide.

Could you please describe why this is beneficial? What is the
configuration case that needs this?

It looks like this is making hostapd accept invalid configuration, e.g.,
with country=US, channel=165, ht_capab=[HT40+]. That configuration is
rejected by design since the explicitly configured secondary channel 169
is not available in US. With this patch, the configuration is not
ignored; instead, hostapd is ignoring the HT40+ part of configuration
silently and falls back to HT20 instead of the configured HT40. I don't
think this is desirable.

Jouni Malinen                                            PGP id EFC895FA

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