Is it possible to change or load older driver for MT7620A?

Installing and Using OpenWrt
1

Hello,

I am user of with cripled mediatek drivers,

Model Asus RT-AC51U
Architecture MediaTek MT7620A ver:2 eco:6
Firmware Version OpenWrt 21.02.0 r16279-5cc0535800 / LuCI openwrt-21.02 branch git-21.231.26241-422c175
Kernel Version 5.4.143

The issue exists since v20+ and it's pretty annoying and results in barely useable router.

I find many users struggle with this issue when both wifi 2.4 and mainly 5ghz just drops all client often and reloads.

Users like https://bugs.openwrt.org/index.php?do=details&task_id=4141 have to revert to v19 of openwrt and I don't want to.

I don't feel like compiling my whole custom OpenWrt distribution but I though the driver backported in v19 could be compiled and loaded after the system boots maybe?

Tainted driver syslog 
hu Jan 27 12:56:42 2022 kern.info kernel: [   35.177868] br-lan: port 3(wlan1) entered blocking state
Thu Jan 27 12:56:42 2022 kern.info kernel: [   35.188512] br-lan: port 3(wlan1) entered disabled state
Thu Jan 27 12:56:42 2022 kern.info kernel: [   35.199543] device wlan1 entered promiscuous mode
Thu Jan 27 12:56:42 2022 kern.info kernel: [   38.708131] IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready
Thu Jan 27 12:56:42 2022 kern.info kernel: [   38.721076] br-lan: port 3(wlan1) entered blocking state
Thu Jan 27 12:56:42 2022 kern.info kernel: [   38.731691] br-lan: port 3(wlan1) entered forwarding state
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.493422] ------------[ cut here ]------------
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.502684] WARNING: CPU: 0 PID: 772 at backports-5.10.42-1/net/mac80211/airtime.c:457 0x835d6180 [mac80211@b748f825+0x7c8d0]
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.525246] Modules linked in: rt2800soc rt2800mmio rt2800lib pppoe ppp_async mt76x0e mt76x0_common iptable_nat xt_state xt_nat xt_conntrack xt_REDIRECT xt_MASQUERADE xt_FLOWOFFLOAD xt_CT rt2x00soc rt2x00mmio rt2x00lib pppox ppp_generic nf_nat nf_flow_table_hw nf_flow_table nf_conntrack mt76x02_lib mt76 mac80211 ipt_REJECT cfg80211 xt_time xt_tcpudp xt_multiport xt_mark xt_mac xt_limit xt_comment xt_TCPMSS xt_LOG slhc nf_reject_ipv4 nf_log_ipv4 nf_defrag_ipv6 nf_defrag_ipv4 iptable_mangle iptable_filter ip_tables crc_ccitt compat ledtrig_usbport nf_log_ipv6 nf_log_common ip6table_mangle ip6table_filter ip6_tables ip6t_REJECT x_tables nf_reject_ipv6 vfat fat nls_utf8 nls_iso8859_1 nls_cp437 leds_gpio ohci_platform ohci_hcd fsl_mph_dr_of ehci_platform ehci_fsl ehci_hcd gpio_button_hotplug usbcore nls_base usb_common
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.669120] CPU: 0 PID: 772 Comm: mt76-tx phy0 Not tainted 5.4.143 #0
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.682044] Stack : 00000000 8005ab38 805c0000 8055f9a0 00000000 00000000 00000000 00000000
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.698686]         00000000 00000000 00000000 00000000 00000000 806f0000 82c63c60 4ffdffe9
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.715358]         82c63cf8 00000000 00000000 00000000 00000038 804eb6c4 65746e69 2e352064
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.731990]         00000000 000001bf 00000000 000a35c0 00000000 82c63c40 00000000 835d6180
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.748604]         00000009 00000014 00000004 00000002 00000000 802ab06c 00000000 806f0000
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.765264]         ...
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.770185] Call Trace:
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.770201] [<8005ab38>] 0x8005ab38
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.782085] [<804eb6c4>] 0x804eb6c4
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.789053] [<835d6180>] 0x835d6180 [mac80211@b748f825+0x7c8d0]
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.800830] [<802ab06c>] 0x802ab06c
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.807777] [<80009790>] 0x80009790
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.814712] [<80009798>] 0x80009798
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.821646] [<800236d0>] 0x800236d0
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.828596] [<835d6180>] 0x835d6180 [mac80211@b748f825+0x7c8d0]
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.840369] [<80023778>] 0x80023778
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.847338] [<835d6180>] 0x835d6180 [mac80211@b748f825+0x7c8d0]
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.859124] [<835836a0>] 0x835836a0 [mac80211@b748f825+0x7c8d0]
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.871162] [<835d6368>] 0x835d6368 [mac80211@b748f825+0x7c8d0]
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.883250] [<835b8ec8>] 0x835b8ec8 [mac80211@b748f825+0x7c8d0]
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.895128] [<835d6448>] 0x835d6448 [mac80211@b748f825+0x7c8d0]
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.906934] [<803379b4>] 0x803379b4
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.913906] [<83552a24>] 0x83552a24 [mt76x02_lib@737a18d7+0x9ce0]
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.926033] [<837e048c>] 0x837e048c [mt76@fdca17df+0x9440]
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.936949] [<837e65ac>] 0x837e65ac [mt76@fdca17df+0x9440]
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.947856] [<8004578c>] 0x8004578c
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.954846] [<837e048c>] 0x837e048c [mt76@fdca17df+0x9440]
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.965818] [<83554fe4>] 0x83554fe4 [mt76x02_lib@737a18d7+0x9ce0]
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.978039] [<837e048c>] 0x837e048c [mt76@fdca17df+0x9440]
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.989045] [<837e0520>] 0x837e0520 [mt76@fdca17df+0x9440]
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8986.999987] [<804ecd48>] 0x804ecd48
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8987.006947] [<8003fdbc>] 0x8003fdbc
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8987.013882] [<8003fc84>] 0x8003fc84
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8987.020829] [<8003fc84>] 0x8003fc84
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8987.027840] [<800050b8>] 0x800050b8
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8987.034804]
Thu Jan 27 12:56:42 2022 kern.warn kernel: [ 8987.037765] ---[ end trace a497b040bebe80dc ]---
2

Due to the change from swconfig to DSA in version 21.0.x, configurations are not upgradeable for the following targeted devices...

ath79 (only TP-Link TL-WR941ND)
bcm4908
gemini
kirkwood
mediatek (most boards)
mvebu
octeon
ramips (mt7621 subtarget only)
realtek

Your device is a mediatek

If you kept your configs when upgrading from 19.07.x, you'll need to re-configure from scratch.

3

No, binary kernel modules have a very strict dependency on the running kernel. Changing backports as a whole -on the source level- wouldn't work reasonably either (they were at v4.19 for 19.07.x, but 21.02.x is using a v5.4 host kernel - while you can use newer backports on older kernels, you can't use older backports on newer kernels). You will have to get your issue fixed, perhaps it already is in master (try it), if found and identified, the fix may be backported from master to 21.02.x (or you'll stick to master until 22.x.0) - if not, it needs to be fixed there first anyways.

1 Like