[PATCH] hw_features: clean center freq for falling back ht40 channels

[Eduardo Abinader]

Hi Jouni,

On 5 February 2017 at 20:16, Jouni Malinen <j at w1.fi> wrote:
> On Mon, Jan 30, 2017 at 11:20:14AM +0100, Eduardo Abinader wrote:
>>  The scenario is very specific: I have both ieee80211n=1 and
>> ieee80211ac=1 also with ht_capab and vht_capab both set. Here is some
>> log;
>
>>  HT40: control channel: 161  secondary channel: 165
>>  HT40 channel pair (161, 165) not allowed
>>  Fallback to 20 MHz
>
> What is this configuration trying to do? There is no 40 MHz channel
> defined with primary channel on 161 and secondary on 165..
>
>>  Completing interface initialization
>>  Mode: IEEE 802.11a  Channel: 161  Frequency: 5805 MHz
>>  DFS chan_idx seems wrong; num-ch: 25 ch-no: -6 conf-ch-no: 161 11n: 1
>> sec-ch: 0 vht-oper-width: 1
>
> And this is furthermore configured to enable 80 MHz VHT? How is that
> supposed to work here? What vht_oper_centr_freq_seg0_idx value is used?
>
>> Interface initialization failed
>>  wlp2s0: interface state HT_SCAN->DISABLED
>>  wlp2s0: AP-DISABLED
>
> And does this actually work in some manner for you with this patch
> applied? I cannot reproduce such behavior, i.e., the failure happens
> here regardless of whether the patch is applied or not..

Yes, with may patch works.

>
> Can you please share the full configuration parameters for setting this
> channel and a debug log from a case where the patch is applied and
> behavior changes to something that could be claimed to be useful?
>

Here it is: http://pastebin.com/gFLaT80W

> IMHO, there is not really much hostapd should do with such configuration
> apart from potentially rejecting it even before trying to do a 40 MHz
> co-ex scan..
>
> --
> Jouni Malinen                                            PGP id EFC895FA