The latest OpenWRT 18.06.4 release lists as one of the highlights:
MT76 wireless driver updates
And there has indeed been progress with respect to WiFi performance and stability, however, there are still some significant issues I'm observing, and wanted to get input from other MT76 users to see if it might be something unique to my hardware (ZBT WE3526 which uses 7612e + 7603) or to the driver updates.
Specifically, with about seven connected devices (3 on 5Ghz rest on 2.4), if there is significant load run through the router (WLAN->WAN (e.g. speedtest)) or even locally (WLAN->LAN (e.g. backup)), the driver panics and restarts. This is from the system log:
If just surfing the web, reading email or doing other non-bulk transfers, it seems to stay up reasonably well, but when running pingplotter for hours at a time, it does detect small periods (<2 seconds) of total ping loss. But there is nothing in the logs to indicate an issue.
Where would one look for more details on what might be going on during those periods, and for the larger restarts of the driver?
Yes, it's the 5Ghz radio supported by the 7612e chip.
Here is the full iw list output:
iw list
Wiphy phy1
max # scan SSIDs: 4
max scan IEs length: 2247 bytes
max # sched scan SSIDs: 0
max # match sets: 0
max # scan plans: 1
max scan plan interval: -1
max scan plan iterations: 0
Retry short limit: 7
Retry long limit: 4
Coverage class: 0 (up to 0m)
Available Antennas: TX 0x3 RX 0x3
Configured Antennas: TX 0x3 RX 0x3
Supported interface modes:
* IBSS
* managed
* AP
* AP/VLAN
* monitor
* mesh point
Band 2:
Capabilities: 0x1ff
RX LDPC
HT20/HT40
SM Power Save disabled
RX Greenfield
RX HT20 SGI
RX HT40 SGI
TX STBC
RX STBC 1-stream
Max AMSDU length: 3839 bytes
No DSSS/CCK HT40
Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
Minimum RX AMPDU time spacing: 4 usec (0x05)
HT TX/RX MCS rate indexes supported: 0-15
VHT Capabilities (0x018001b0):
Max MPDU length: 3895
Supported Channel Width: neither 160 nor 80+80
RX LDPC
short GI (80 MHz)
TX STBC
VHT RX MCS set:
1 streams: MCS 0-9
2 streams: MCS 0-9
3 streams: not supported
4 streams: not supported
5 streams: not supported
6 streams: not supported
7 streams: not supported
8 streams: not supported
VHT RX highest supported: 0 Mbps
VHT TX MCS set:
1 streams: MCS 0-9
2 streams: MCS 0-9
3 streams: not supported
4 streams: not supported
5 streams: not supported
6 streams: not supported
7 streams: not supported
8 streams: not supported
VHT TX highest supported: 0 Mbps
Frequencies:
* 5180 MHz [36] (23.0 dBm)
* 5200 MHz [40] (23.0 dBm)
* 5220 MHz [44] (23.0 dBm)
* 5240 MHz [48] (23.0 dBm)
* 5260 MHz [52] (23.0 dBm) (radar detection)
* 5280 MHz [56] (23.0 dBm) (radar detection)
* 5300 MHz [60] (23.0 dBm) (radar detection)
* 5320 MHz [64] (23.0 dBm) (radar detection)
* 5500 MHz [100] (23.0 dBm) (radar detection)
* 5520 MHz [104] (23.0 dBm) (radar detection)
* 5540 MHz [108] (23.0 dBm) (radar detection)
* 5560 MHz [112] (23.0 dBm) (radar detection)
* 5580 MHz [116] (23.0 dBm) (radar detection)
* 5600 MHz [120] (23.0 dBm) (radar detection)
* 5620 MHz [124] (23.0 dBm) (radar detection)
* 5640 MHz [128] (23.0 dBm) (radar detection)
* 5660 MHz [132] (23.0 dBm) (radar detection)
* 5680 MHz [136] (23.0 dBm) (radar detection)
* 5700 MHz [140] (23.0 dBm) (radar detection)
* 5745 MHz [149] (30.0 dBm)
* 5765 MHz [153] (30.0 dBm)
* 5785 MHz [157] (30.0 dBm)
* 5805 MHz [161] (30.0 dBm)
* 5825 MHz [165] (30.0 dBm)
valid interface combinations:
* #{ IBSS } <= 1, #{ managed, AP, mesh point } <= 8,
total <= 8, #channels <= 1, STA/AP BI must match, radar detect widths: { 20 MHz (no HT), 20 MHz, 40 MHz, 80 MHz }
HT Capability overrides:
* MCS: ff ff ff ff ff ff ff ff ff ff
* maximum A-MSDU length
* supported channel width
* short GI for 40 MHz
* max A-MPDU length exponent
* min MPDU start spacing
Device supports VHT-IBSS.
Wiphy phy0
max # scan SSIDs: 4
max scan IEs length: 2257 bytes
max # sched scan SSIDs: 0
max # match sets: 0
max # scan plans: 1
max scan plan interval: -1
max scan plan iterations: 0
Retry short limit: 7
Retry long limit: 4
Coverage class: 0 (up to 0m)
Available Antennas: TX 0x3 RX 0x3
Supported interface modes:
* IBSS
* managed
* AP
* AP/VLAN
* monitor
* mesh point
Band 1:
Capabilities: 0x1fe
HT20/HT40
SM Power Save disabled
RX Greenfield
RX HT20 SGI
RX HT40 SGI
TX STBC
RX STBC 1-stream
Max AMSDU length: 3839 bytes
No DSSS/CCK HT40
Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
Minimum RX AMPDU time spacing: 4 usec (0x05)
HT TX/RX MCS rate indexes supported: 0-15
Frequencies:
* 2412 MHz [1] (30.0 dBm)
* 2417 MHz [2] (30.0 dBm)
* 2422 MHz [3] (30.0 dBm)
* 2427 MHz [4] (30.0 dBm)
* 2432 MHz [5] (30.0 dBm)
* 2437 MHz [6] (30.0 dBm)
* 2442 MHz [7] (30.0 dBm)
* 2447 MHz [8] (30.0 dBm)
* 2452 MHz [9] (30.0 dBm)
* 2457 MHz [10] (30.0 dBm)
* 2462 MHz [11] (30.0 dBm)
* 2467 MHz [12] (disabled)
* 2472 MHz [13] (disabled)
* 2484 MHz [14] (disabled)
valid interface combinations:
* #{ IBSS } <= 1, #{ managed, AP, mesh point } <= 4,
total <= 4, #channels <= 1, STA/AP BI must match
HT Capability overrides:
* MCS: ff ff ff ff ff ff ff ff ff ff
* maximum A-MSDU length
* supported channel width
* short GI for 40 MHz
* max A-MPDU length exponent
* min MPDU start spacing
Thanks for the feedback on your device, and could you please run some load through them by performing a couple of DSLreports.com/speedtest back-to-back.
These were both correlated to burst of substantial web request activity from an HP Envy laptop running Windows 10. Laptop is a few feet from the router and connected to the 5Ghz (7612e-based) radio.
I have some preliminary hints at what is going on, and it seems that these crashes are triggered when there is a mix of close (really close, about a foot or two) clients and further away clients (up to 30', a wall or two).
I would suspect that the Auto Gain Control (AGC) related handling in each radio is involved in this scenario.
Now that all clients are a minimum of 5' away from the routers WiFi, I have not seen a single wifi driver crash nor system reboot. Same client count and usage as prior days, so it is looking positive.
Will let it run for a day or so, and move them close again.
In preparation for that, any low level stats I should collect to document the works vs. crashes scenarios so I can write up a bug report?
@TopDog hi. We are currently working on a router MTK 7603 + 7612E and facing same issue. And it reproduces periodically, not on all routers. Were you able to find the reason for this?
So from attempts to improve the mt76 driver stability, setting transmit power above 20 dBm will cause this issue.
The mt76 has a default max_power setting of 30 dBm, and im sure some 5ghz chipsets have this capability, but its possible this will only work with increasing power to the chip?, maybe manipulating the gpio pins?
So im maintaining my own release based on v19.07.5 release
I've been adding backport patches etc, testing high level dBm levels on the mt7612e, cause this hardware reset issues. Its also apparent on my other device U7621-01 device.
My source code can be used for other mt7621 devices, just select a different profile for your device, then build - Config-min example and build script is there.