On Sun, Mar 22, 2026 at 09:07:37PM +0100, Kirill A. Korinsky wrote:
> Unfortently, the machine with iwx can't move beyond ~300 mbps. I've tried
> both iwx and 1G Ethernet as USB dognle, so, I can't prove that.

Our USB stack tends to be slow, yes. I've seen this with my Ethernet
dongles as well.

> But Unifi thinks that this machine is connected as 42 dBm Ch. 64 (5 GHz, 160
> MHz) and it says: Rx Rate 780 Mbps; Tx Rate 1.17 Gbps.

This tells us that 160 MHz is definitely working from the AP towards iwx.
1.17 Gbps can only occur with a 160 Mhz channel.

But this doesn't tell us whether 160MHz Tx from iwx to the AP is working
because 780mbps is ambiguous. It could be MCS 8 or 9 at 80 MHZ or MCS 4
at 160 MHz (assuming 2 streams). See mcsindex.com

The AP could simply be listing the client as 160MHz-capable based on
what iwx is sending in VHT capabilities.

I don't believe that the Tx side is necessarily broken. But it would be
nice to see some evidence of iwx firmware deciding to use 160 Mhz
bandwidth during transmit, just to confirm that the driver is
configuring this correctly.

> And in beacon I see: Channel Width: 80 MHz, 160 MHz or 80+80 MHz BSS
> Bandwidth (1).

I checked our net80211 headers first, which still list value 2 as 160 MHz.

Turns out the 802.11 spec has since deprecated values 2 and 3. Wireshark is
correct that this value by itself doesn't mean anything and can be set to 1
in all cases. We need to check the two bytes following this value specify
the center frequency of two 80 MHz portions of a 160 MHz channel.