Arch Linux

Beemo

Member

Registered: 2024-12-20

Posts: 109

Intel unable to see 6GHz hotspot in passive scan mode

I have a 6GHz only AP / hotspot sending beacons frames on channel 5 (a Preferred Scanning Channel), every 100 TU (102.4ms), and it does not support "FILS_DISCOVERY" or "UNSOL_BCAST_PROBE_RESP".

My phone and laptop with Mediatek chip can see it, but my laptop with Intel AX211 cannot.

6E is not disabled by the OEM (0 actually means enabled)

$ echo "\_SB_.PC00.CNVW._DSM bF21202BF8F784DC6A5B31F738E285ADE 0 3 0" | sudo tee /proc/acpi/call
$ sudo cat /proc/acpi/call
{0x00}

Frequency not disabled by Intel LAR, but limited to passive-scan.

❯ iw reg get
phy#0 (self-managed)
country (redacted): DFS-UNSET
        (5945 - 6425 @ 160), (6, 22), (N/A), NO-OUTDOOR, AUTO-BW, IR-CONCURRENT, NO-320MHZ, PASSIVE-SCAN

p.s. It's using a 80Hz channel 5945-6025, broadcasting beacons on channel 5.

Last edited by Beemo (Yesterday 12:07:09)

Beemo

Member

Registered: 2024-12-20

Posts: 109

Re: Intel unable to see 6GHz hotspot in passive scan mode

AI claims it's a bug in the Intel driver: Since it's a PSC it's using the 10ms IWL_SCAN_DWELL_ACTIVE, but since passive-scan disallows active scan, it's using 10ms dwell time for listening to beacons, which is too short for my 100ms interval.

Not sure how true it is. I had enough reading spaghetti code for the day...

Beemo

Member

Registered: 2024-12-20

Posts: 109

Re: Intel unable to see 6GHz hotspot in passive scan mode

I changed the beacon interval to 20 TU.

NOTE 1—A 6 GHz-only AP intends to be efficiently discovered by STAs using scanning in the 6 GHz band if it
schedules for transmission FILS Discovery, Beacon, or unsolicited Probe Response frames every 20 TUs or less.

I also disconnected my Wi-Fi, and this results in seeing more beacon frames.

And... the beacon frames do show up in Wireshark (monitor mode), but nmcli dev wifi does not list my SSID in the result.

Last edited by Beemo (Yesterday 12:19:08)