MT7612E still firmware crashes on x86_64 laptop

Previously wifi was usable in station mode with disable_ht=1 and disable_vht=1 set. Now, after recent commits (i'm on fd892bc033fbfad7b1a5bcba1432709a74327a1e), it crashes immediately after connecting once any traffic goes over the link:

[   97.705962] mt76x2e 0000:02:00.0: MCU message 31 (seq 6) timed out
[   97.756817] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[   97.756823] mt76x2e 0000:02:00.0: Build: 1
[   97.756827] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[   97.779403] mt76x2e 0000:02:00.0: Firmware running!
[   97.780210] ieee80211 phy0: Hardware restart was requested
[   98.799811] mt76x2e 0000:02:00.0: MCU message 2 (seq 8) timed out
[   99.733597] mt76x2e 0000:02:00.0: MCU message 31 (seq 9) timed out
[  100.101205] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  100.101210] mt76x2e 0000:02:00.0: Build: 1
[  100.101213] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  100.123795] mt76x2e 0000:02:00.0: Firmware running!
[  100.124641] ieee80211 phy0: Hardware restart was requested
[  101.147616] mt76x2e 0000:02:00.0: MCU message 2 (seq 11) timed out
[  101.515282] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  101.515288] mt76x2e 0000:02:00.0: Build: 1
[  101.515291] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  101.540124] mt76x2e 0000:02:00.0: Firmware running!
[  101.540776] ieee80211 phy0: Hardware restart was requested
[  102.588311] mt76x2e 0000:02:00.0: MCU message 2 (seq 13) timed out
[  103.065953] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  103.065957] mt76x2e 0000:02:00.0: Build: 1
[  103.065958] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  103.091848] mt76x2e 0000:02:00.0: Firmware running!
[  103.092525] ieee80211 phy0: Hardware restart was requested
[  104.109009] mt76x2e 0000:02:00.0: MCU message 2 (seq 15) timed out
[  104.373208] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  104.373212] mt76x2e 0000:02:00.0: Build: 1
[  104.373214] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  104.395841] mt76x2e 0000:02:00.0: Firmware running!
[  104.396516] ieee80211 phy0: Hardware restart was requested
[  104.396568] NOHZ: local_softirq_pending 08
[  105.416328] mt76x2e 0000:02:00.0: MCU message 31 (seq 1) timed out
[  105.783989] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  105.783993] mt76x2e 0000:02:00.0: Build: 1
[  105.783995] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  105.809537] mt76x2e 0000:02:00.0: Firmware running!
[  105.810229] ieee80211 phy0: Hardware restart was requested
[  106.830350] mt76x2e 0000:02:00.0: MCU message 2 (seq 3) timed out
[  107.097891] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  107.097895] mt76x2e 0000:02:00.0: Build: 1
[  107.097897] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  107.123330] mt76x2e 0000:02:00.0: Firmware running!
[  107.124044] ieee80211 phy0: Hardware restart was requested
[  107.124197] NOHZ: local_softirq_pending 08
[  108.137617] mt76x2e 0000:02:00.0: MCU message 2 (seq 5) timed out
[  108.401902] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  108.401907] mt76x2e 0000:02:00.0: Build: 1
[  108.401910] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  108.421163] kauditd_printk_skb: 8 callbacks suppressed
[  108.424477] mt76x2e 0000:02:00.0: Firmware running!
[  108.425472] ieee80211 phy0: Hardware restart was requested
[  108.425655] NOHZ: local_softirq_pending 08
[  109.444921] mt76x2e 0000:02:00.0: MCU message 2 (seq 7) timed out
[  109.805846] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  109.805850] mt76x2e 0000:02:00.0: Build: 1
[  109.805853] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  109.831296] mt76x2e 0000:02:00.0: Firmware running!
[  109.832028] ieee80211 phy0: Hardware restart was requested
[  110.858982] mt76x2e 0000:02:00.0: MCU message 2 (seq 9) timed out
[  111.330043] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  111.330046] mt76x2e 0000:02:00.0: Build: 1
[  111.330049] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  111.352522] mt76x2e 0000:02:00.0: Firmware running!
[  111.353199] ieee80211 phy0: Hardware restart was requested
[  112.379652] mt76x2e 0000:02:00.0: MCU message 30 (seq 10) timed out
[  112.647357] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  112.647361] mt76x2e 0000:02:00.0: Build: 1
[  112.647363] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  112.666496] mt76x2e 0000:02:00.0: Firmware running!
[  112.667164] ieee80211 phy0: Hardware restart was requested
[  112.667295] NOHZ: local_softirq_pending 08
[  113.686942] mt76x2e 0000:02:00.0: MCU message 2 (seq 12) timed out
[  114.054811] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  114.054815] mt76x2e 0000:02:00.0: Build: 1
[  114.054817] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  114.073825] mt76x2e 0000:02:00.0: Firmware running!
[  114.074497] ieee80211 phy0: Hardware restart was requested
[  115.100932] mt76x2e 0000:02:00.0: MCU message 2 (seq 14) timed out
[  115.361839] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  115.361842] mt76x2e 0000:02:00.0: Build: 1
[  115.361844] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  115.381139] mt76x2e 0000:02:00.0: Firmware running!
[  115.381811] ieee80211 phy0: Hardware restart was requested
[  115.381940] NOHZ: local_softirq_pending 08
[  116.408384] mt76x2e 0000:02:00.0: MCU message 2 (seq 1) timed out
[  116.776075] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  116.776079] mt76x2e 0000:02:00.0: Build: 1
[  116.776082] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  116.795146] mt76x2e 0000:02:00.0: Firmware running!
[  116.795834] ieee80211 phy0: Hardware restart was requested
[  117.822220] mt76x2e 0000:02:00.0: MCU message 2 (seq 3) timed out
[  118.293347] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  118.293351] mt76x2e 0000:02:00.0: Build: 1
[  118.293353] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  118.309199] mt76x2e 0000:02:00.0: Firmware running!
[  118.309873] ieee80211 phy0: Hardware restart was requested
[  119.316248] mt76x2e 0000:02:00.0: MCU message 30 (seq 4) timed out
[  119.694179] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  119.694182] mt76x2e 0000:02:00.0: Build: 1
[  119.694184] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  119.716536] mt76x2e 0000:02:00.0: Firmware running!
[  119.717225] ieee80211 phy0: Hardware restart was requested
[  120.730313] mt76x2e 0000:02:00.0: MCU message 2 (seq 6) timed out
[  121.098394] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  121.098398] mt76x2e 0000:02:00.0: Build: 1
[  121.098400] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  121.117183] mt76x2e 0000:02:00.0: Firmware running!
[  121.117850] ieee80211 phy0: Hardware restart was requested
[  122.144355] mt76x2e 0000:02:00.0: MCU message 2 (seq 8) timed out
[  122.512034] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  122.512036] mt76x2e 0000:02:00.0: Build: 1
[  122.512038] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  122.527800] mt76x2e 0000:02:00.0: Firmware running!
[  122.528358] ieee80211 phy0: Hardware restart was requested
[  123.531649] mt76x2e 0000:02:00.0: MCU message 2 (seq 10) timed out
[  123.796029] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  123.796033] mt76x2e 0000:02:00.0: Build: 1
[  123.796035] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  123.821484] mt76x2e 0000:02:00.0: Firmware running!
[  123.822178] ieee80211 phy0: Hardware restart was requested
[  123.822315] NOHZ: local_softirq_pending 08
[  124.838907] mt76x2e 0000:02:00.0: MCU message 2 (seq 12) timed out
[  125.103620] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  125.103623] mt76x2e 0000:02:00.0: Build: 1
[  125.103626] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  125.129071] mt76x2e 0000:02:00.0: Firmware running!
[  125.129755] ieee80211 phy0: Hardware restart was requested
[  125.129782] NOHZ: local_softirq_pending 08
[  126.146210] mt76x2e 0000:02:00.0: MCU message 31 (seq 13) timed out
[  126.410444] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  126.410447] mt76x2e 0000:02:00.0: Build: 1
[  126.410449] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  126.435874] mt76x2e 0000:02:00.0: Firmware running!
[  126.436572] ieee80211 phy0: Hardware restart was requested
[  126.436763] NOHZ: local_softirq_pending 08
[  127.453455] mt76x2e 0000:02:00.0: MCU message 2 (seq 1) timed out
[  127.821415] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  127.821419] mt76x2e 0000:02:00.0: Build: 1
[  127.821421] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  127.840389] mt76x2e 0000:02:00.0: Firmware running!
[  127.841058] ieee80211 phy0: Hardware restart was requested
[  128.867516] mt76x2e 0000:02:00.0: MCU message 2 (seq 3) timed out
[  129.132228] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  129.132231] mt76x2e 0000:02:00.0: Build: 1
[  129.132234] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  129.157755] mt76x2e 0000:02:00.0: Firmware running!
[  129.158427] ieee80211 phy0: Hardware restart was requested
[  129.158562] NOHZ: local_softirq_pending 08
[  130.174806] mt76x2e 0000:02:00.0: MCU message 2 (seq 5) timed out
[  130.439227] mt76x2e 0000:02:00.0: Firmware Version: 0.0.00
[  130.439231] mt76x2e 0000:02:00.0: Build: 1
[  130.439233] mt76x2e 0000:02:00.0: Build Time: 201507311614____
[  130.464669] mt76x2e 0000:02:00.0: Firmware running!
[  130.465375] ieee80211 phy0: Hardware restart was requested
[  130.465515] NOHZ: local_softirq_pending 08

Running:

Linux 5.5.4-arch1-1 #1 SMP PREEMPT Sat, 15 Feb 2020 00:36:29 +0000 x86_64 GNU/Linux

The same hardware works fine with the iwlwifi card which originally shipped with it and also ath9k-based mPCIe modules work flawlessly.

Start by reproducing the mt76x2e failure in station mode with disable_ht=1 and disable_vht=1, using the reported fd892bc033fbfad7b1a5bcba1432709a74327a1e revision and Linux 5.5.4. Compare behavior around the recent commits and use the MCU timeout and firmware-restart messages as the failure signal. Done means traffic no longer causes repeated firmware crashes or hardware restarts.