MT7615 DBDC issues

For Developers
1

Hi all,

Trying to get MT7615 working on a MT7621 dev board, I started by installing kmod-mt7615-common and kmod-mt7615-firmware and the card was picked up:

[   14.948147] mt7615e 0000:01:00.0: enabling device (0000 -> 0002)
[   15.039187] mt7615e 0000:01:00.0: HW/SW Version: 0x8a108a10, Build Time: 20180518100604a
[   16.513581] mt7615e 0000:01:00.0: N9 Firmware Version: _reserved_, Build Time: 20200814163649
[   16.785015] mt7615e 0000:01:00.0: CR4 Firmware Version: _reserved_, Build Time: 20190415154149

iw list only returned one phy, phy0, but running echo 1 > /sys/kernel/debug/ieee80211/phy0/mt76/dbdc made phy1 appear, so all good there too:

# iw list | grep phy
Wiphy phy1
        wiphy index: 1
Wiphy phy0
        wiphy index: 0

Reading up on older forum posts, both here and on other sites, the suggestion is to set the first phy to run on 2.4GHZ, but the first hurdle is that I can't seem to get it to work on 2.4GHz - this config does not work:

config wifi-device 'radio0'
        option disabled '0'
        option type 'mac80211'
        option phy 'phy0'
        option country 'GB'
        option cell_density '0'
        option band '2g'
        option htmode 'HT40'
        option channel '1'

config wifi-iface 'default_radio0'
        option device 'radio0'
        option network 'lan'
        option mode 'ap'
        option ssid 'OpenWrt-xxy'
        option encryption 'none'

But this 5GHz config works just fine (only changes are options: band, htmode and channel):

config wifi-device 'radio0'
        option disabled '0'
        option type 'mac80211'
        option phy 'phy0'
        option country 'GB'
        option cell_density '0'
        option band '5g'
        option htmode 'VHT80'
        option channel '36'

config wifi-iface 'default_radio0'
        option device 'radio0'
        option network 'lan'
        option mode 'ap'
        option ssid 'OpenWrt-xxy'
        option encryption 'none'

When I say it doesn't work: I can't see it advertised and/or connect to it from another device

Am I missing something obvious here?

I can't yet validate this, but would the following be the right config for running 2 APs, one on 2.4GHz and another on 5GHz? It's a mashup of various configs dug out of forum posts and Github issues:

config wifi-device 'radio0'
        option disabled '0'
        option type 'mac80211'
        option phy 'phy0'
        option serialize '1'
        option country 'GB'
        option cell_density '0'
        option band '2g'
        option htmode 'HT40'
        option channel '1'

config wifi-device 'radio1'
        option disabled '0'
        option type 'mac80211'
        option phy 'phy1'
        option serialize '1'
        option country 'GB'
        option cell_density '0'
        option band '5g'
        option htmode 'VHT80'
        option channel '36'
        option txpower '20'

config wifi-iface 'default_radio0'
        option device 'radio0'
        option network 'lan'
        option mode 'ap'
        option ssid 'OpenWrt-24'
        option encryption 'none'

config wifi-iface 'default_radio1'
        option device 'radio1'
        option network 'lan'
        option mode 'ap'
        option ssid 'OpenWrt-5'
        option encryption 'none'

Thanks in advance for any pointers/working config suggestions!

2

Well, they cant both be radio0

3

That's the isolated config, so I am not trying to run two radios there.

With a single radio, radio0, 2.4GHz operation does not seem to work but changing that same radio to 5GHz parameters magically works.

To be clear: My goal is to run both radios at the same time but I am going step by step here.

4

Try calling 2.4 radio1.

5

Considering there is only one radio defined in my test config, to figure out why 2.4GHz does not work, I don't understand how renaming that single radio to something else would fix the problem?

Here's the test config, in its entirety, that does work with 5GHz parameters:

root@OpenWrt:/etc/config# cat wireless
config wifi-device 'radio0'
        option disabled '0'
        option type 'mac80211'
        option phy phy0
        option country 'GB'
        option cell_density '0'
        option band '5g'
        option htmode 'VHT80'
        option channel '36'

config wifi-iface 'default_radio0'
        option device 'radio0'
        option network 'lan'
        option mode 'ap'
        option ssid 'OpenWrt-xxy'
        option encryption 'none'

And with the parameters changed for 2.4GHz, that does not work:

config wifi-device 'radio0'
        option disabled '0'
        option type 'mac80211'
        option phy phy0
        option country 'GB'
        option cell_density '0'
        option band '2g'
        option htmode 'HT40'
        option channel '1'

config wifi-iface 'default_radio0'
        option device 'radio0'
        option network 'lan'
        option mode 'ap'
        option ssid 'OpenWrt-xxy'
        option encryption 'none'

Essentially: I am trying to figure out why the 2.4GHz AP does not work, before moving on and adding the second radio (with phy1) into the same config.

Unrelated to this particular problem, but promising data point: Changing option phy phy0 to option phy phy1 works for the 5GHz config, so I have slightly higher confidence in DBDC working if I can figure out why the 2.4GHz operation does not work...

6

Bandwidth set to 40?
Try 20.
If that does not work try "Legacy"

7

Sadly, no luck. I have tried pretty much every permutation of parameters for band, hwmode, htmode and even channel but 2.4GHz operation does not work, while 5GHz works without any issues.

This is with the current stable (23.05.2) release, and current versions of kmod-mt7615-common and kmod-mt7615-firmware.

8

Doing a search of the wi-fi chip I found that until recently people had trouble getting 5G working.

First thing that will happen if I link a thread will be the reply "that is not my problem" so I have taken "the answer is out there" approach.

9

I don't know the particular board, but IMHO you cannot choose.

Even before /etc/config/ entries, what do you get from iwinfo phy0 freq?

For instance, on my mt7615dn I get the following, telling me phy0 is 2.4 and phy1 is 5.

root@OpenWrt:~# iwinfo phy0 freq
  2.412 GHz (Band: 2.4 GHz, Channel 1) [NO_HT40-, NO_80MHZ, NO_160MHZ]
  2.417 GHz (Band: 2.4 GHz, Channel 2) [NO_HT40-, NO_80MHZ, NO_160MHZ]
  2.422 GHz (Band: 2.4 GHz, Channel 3) [NO_HT40-, NO_80MHZ, NO_160MHZ]
  2.427 GHz (Band: 2.4 GHz, Channel 4) [NO_HT40-, NO_80MHZ, NO_160MHZ]
  2.432 GHz (Band: 2.4 GHz, Channel 5) [NO_80MHZ, NO_160MHZ]
  2.437 GHz (Band: 2.4 GHz, Channel 6) [NO_80MHZ, NO_160MHZ]
  2.442 GHz (Band: 2.4 GHz, Channel 7) [NO_80MHZ, NO_160MHZ]
  2.447 GHz (Band: 2.4 GHz, Channel 8) [NO_80MHZ, NO_160MHZ]
  2.452 GHz (Band: 2.4 GHz, Channel 9) [NO_80MHZ, NO_160MHZ]
  2.457 GHz (Band: 2.4 GHz, Channel 10) [NO_HT40+, NO_80MHZ, NO_160MHZ]
  2.462 GHz (Band: 2.4 GHz, Channel 11) [NO_HT40+, NO_80MHZ, NO_160MHZ]
  2.467 GHz (Band: 2.4 GHz, Channel 12) [NO_HT40+, NO_80MHZ, NO_160MHZ]
  2.472 GHz (Band: 2.4 GHz, Channel 13) [NO_HT40+, NO_80MHZ, NO_160MHZ]
root@OpenWrt:~# iwinfo phy1 freq
* 5.180 GHz (Band: 5 GHz, Channel 36) [NO_HT40-, INDOOR_ONLY]
  5.200 GHz (Band: 5 GHz, Channel 40) [INDOOR_ONLY]
  5.220 GHz (Band: 5 GHz, Channel 44) [INDOOR_ONLY]
  5.240 GHz (Band: 5 GHz, Channel 48) [INDOOR_ONLY]
  5.260 GHz (Band: 5 GHz, Channel 52) [INDOOR_ONLY]
  5.280 GHz (Band: 5 GHz, Channel 56) [INDOOR_ONLY]
  5.300 GHz (Band: 5 GHz, Channel 60) [INDOOR_ONLY]
  5.320 GHz (Band: 5 GHz, Channel 64) [NO_HT40+, INDOOR_ONLY]
  5.500 GHz (Band: 5 GHz, Channel 100) [NO_HT40-, INDOOR_ONLY]
  5.520 GHz (Band: 5 GHz, Channel 104) [INDOOR_ONLY]
  5.540 GHz (Band: 5 GHz, Channel 108) [INDOOR_ONLY]
  5.560 GHz (Band: 5 GHz, Channel 112) [INDOOR_ONLY]
  5.580 GHz (Band: 5 GHz, Channel 116) [INDOOR_ONLY]
  5.600 GHz (Band: 5 GHz, Channel 120) [INDOOR_ONLY]
  5.620 GHz (Band: 5 GHz, Channel 124) [INDOOR_ONLY]
  5.640 GHz (Band: 5 GHz, Channel 128) [INDOOR_ONLY]
  5.660 GHz (Band: 5 GHz, Channel 132) [INDOOR_ONLY]
  5.680 GHz (Band: 5 GHz, Channel 136) [INDOOR_ONLY]
  5.700 GHz (Band: 5 GHz, Channel 140) [INDOOR_ONLY]
  5.720 GHz (Band: 5 GHz, Channel 144) [NO_HT40+, INDOOR_ONLY]
  5.745 GHz (Band: 5 GHz, Channel 149) [NO_HT40-]
  5.765 GHz (Band: 5 GHz, Channel 153)
  5.785 GHz (Band: 5 GHz, Channel 157)
  5.805 GHz (Band: 5 GHz, Channel 161)
  5.825 GHz (Band: 5 GHz, Channel 165)
  5.845 GHz (Band: 5 GHz, Channel 169)
  5.865 GHz (Band: 5 GHz, Channel 173) [NO_HT40+]