[Help]: mt7921u AX3000 unusable as a AP with more than 16 stations/clients

[kbmetz]

Checklist

• I acknowledge that support is provided on a best-effort basis.
• I acknowledge that the authors and contributors to this repository cannot be held responsible for the results of my use of any information contained in or linked from this repository.

uname

Linux pi 6.8.0-1017-raspi #19-Ubuntu SMP PREEMPT_DYNAMIC Fri Dec 6 20:45:12 UTC 2024 aarch64 aarch64 aarch64 GNU/Linux

lsusb

Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 002: ID 2109:3431 VIA Labs, Inc. Hub Bus 001 Device 003: ID 1997:2433 Shenzhen Riitek Technology Co., Ltd wireless mini keyboard with touchpad Bus 001 Device 004: ID 0781:5583 SanDisk Corp. Ultra Fit Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 002 Device 002: ID 0e8d:7961 MediaTek Inc. Wireless_Device Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

rfkill

0: hci0: Bluetooth Soft blocked: no Hard blocked: no 1: phy0: Wireless LAN Soft blocked: no Hard blocked: no 3: phy2: Wireless LAN Soft blocked: no Hard blocked: no

dkms

there is no dkms output

iw

phy#2
	Interface wlxe84e06ad13fa
		ifindex 6
		wdev 0x200000001
		addr e8:4e:06:ad:13:fa
		type AP
		txpower 3.00 dBm
		multicast TXQ:
			qsz-byt	qsz-pkt	flows	drops	marks	overlmt	hashcol	tx-bytes	tx-packets
			0	0	0	0	0	0	0	0		0

What happened?

I'm attempting to run an AP based off hostapd. Everything is configured and working but once 16-20 clients have joined i start getting the following error
hostapd: wlxe84e06ad13fa: STA xx:xx:xx:xx:xx:xx IEEE 802.11: Could not add STA to kernel driver

Restarting resolves the issue. And if I keep it under 10 stations there is also no issue.

If this is a known issue that only mediatek can resolve then I recommend this adapter description on this repo be amended to make note of this limitation.

This issue is also referenced here:
#369
https://forum.openwrt.org/t/reference-for-number-of-supported-stations-in-different-wifi-hardware/156535

Is is possible to recompile the module with the limits increased? I like this adapter but the specific use case is for an AP

Also, I'm able to run hostapd with the same configuration on a rtl8812au and it supports up to 30 stations without issue.

[morrownr]

@kbmetz

If this is a known issue that only mediatek can resolve ...

I cannot say that this is a known issue. I have used my Edup EP-AX1672 (mt7921au chip) as an AP a lot. I probably don't get over maybe 12-16 clients so maybe I could have avoided the issue but I cannot recall anyone else bringing this up. I took a look at the OpenWRT link.

You might report this to

https://bugzilla.kernel.org/

and

https://github.com/openwrt/mt76

I'd be interesting to know what you find out.

[kbmetz]

Thanks

[ExcaliburUBW]

My EDUP AX3000 doesn't work at all.

[morrownr]

@kbmetz

I was thinking that you could change the following line:

#define MT792x_WTBL_STA (MT792x_WTBL_RESERVED - MT792x_MAX_INTERFACES)

to

#define MT792x_WTBL_STA (MT792x_WTBL_RESERVED + MT792x_MAX_INTERFACES)

Recompile and see if it works. That might not be how a real patch for this issue should be done but for a quick and dirty test it should work. That way you could mention it in the problem reports you file.

[morrownr]

Hi @ExcaliburUBW

My EDUP AX3000 doesn't work at all.

Not much to go on. Is your adapter an EDUP EP-AX1672 or EDUP EP-AX1673?

What distro and what kernel are we talking about?

Describe the problem?

[kbmetz]

@kbmetz

I was thinking that you could change the following line:

#define MT792x_WTBL_STA (MT792x_WTBL_RESERVED - MT792x_MAX_INTERFACES)

to

#define MT792x_WTBL_STA (MT792x_WTBL_RESERVED + MT792x_MAX_INTERFACES)

Recompile and see if it works. That might not be how a real patch for this issue should be done but for a quick and dirty test it should work. That way you could mention it in the problem reports you file.

The irony is that I bought this specifically so I wouldn't have to recompile anything as I've had to do with the rtl8812au. But it would appear there's no other options. I'll give that a shot once I can figure out how to compile it on the Ubuntu system.

[morrownr]

The irony is that I bought this specifically so I wouldn't have to recompile anything as I've had to do with the rtl8812au.

Depending on what we find out:

• I will add a note about a 16 client limit in AP mode for the mt7921au.

• And we could figure out what the best patch would be and submit a patch to mainline to see what happens.

Also, a new mac80211 driver (in-kernel) for the rtl8812au just went into kernel 6.13. It should work well in 6.13 but there are some additional patches going into 6.14 so I'd say best performance with 6.14 and later. If you want to try it now:

https://github.com/lwfinger/rtw88

[kbmetz]

The irony is that I bought this specifically so I wouldn't have to recompile anything as I've had to do with the rtl8812au.

Depending on what we find out:

* I will add a note about a 16 client limit in AP mode for the mt7921au.

The AX3000 that I have is loading the mt7921u. Should it be using the mt7921au?

* And we could figure out what the best patch would be and submit a patch to mainline to see what happens.

Agreed. I'm going to read up and see about recompiling it with those options

Also, a new mac80211 driver (in-kernel) for the rtl8812au just went into kernel 6.13. It should work well in 6.13 but there are some additional patches going into 6.14 so I'd say best performance with 6.14 and later. If you want to try it now:

https://github.com/lwfinger/rtw88

That would be great! Thanks for the mention

[morrownr]

The AX3000 that I have is loading the mt7921u. Should it be using the mt7921au?

No, the driver for the mt7921au chip is the mt7921u.