Re: [PATCH v2 07/22] mac80211: s1g: choose scanning width based on frequency

Thomas Pedersen
2020-09-21T05:06:54Z

On 2020-09-18 03:40, Johannes Berg wrote:
> On Mon, 2020-08-31 at 13:55 -0700, Thomas Pedersen wrote:
>> An S1G BSS can beacon at either 1 or 2 MHz and the channel
>> width is unique to a given frequency. Ignore scan channel
>> width for now and use the allowed channel width.
>>
>> Signed-off-by: Thomas Pedersen <thomas@adapt-ip.com>
>> ---
>> net/mac80211/scan.c | 17 +++++++++++++++++
>> 1 file changed, 17 insertions(+)
>>
>> diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
>> index 5ac2785cdc7b..5002791fe165 100644
>> --- a/net/mac80211/scan.c
>> +++ b/net/mac80211/scan.c
>> @@ -905,6 +905,17 @@ static void
>> ieee80211_scan_state_set_channel(struct ieee80211_local *local,
>> local->scan_chandef.center_freq1 = chan->center_freq;
>> local->scan_chandef.freq1_offset = chan->freq_offset;
>> local->scan_chandef.center_freq2 = 0;
>> +
>> + /* For scanning on the S1G band, ignore scan_width (which is
>> constant
>> + * across all channels) for now since channel width is specific to
>> each
>> + * channel. Detect the required channel width here and likely
>> revisit
>> + * later. Maybe scan_width could be used to build the channel scan
>> list?
>> + */
>> + if (chan->band == NL80211_BAND_S1GHZ) {
>> + local->scan_chandef.width = ieee80211_s1g_channel_width(chan);
>> + goto set_channel;
>> + }
>
> nit: double space after 'goto'
>
> but really I came to say that this probably changes then, if you don't
> convince me about the stuff in the previous patch review? :)
>
> So I'm leaving this patch also for now - have applied 1-5 so far.

Thanks. I'm not really sure what else would make sense here?
scan_req->scan_width is constant across all channels in
scan_req->channels so for S1G we can either filter the scan_req channels
list based on scan_width (kind of strange and unexpected), or deduce the
correct chanenl width for each channel in the list and ignore scan_width
(mostly correct). It seems like scan_width is currently only used for
scanning at 5 or 10MHz anyway?

--
thomas