mt7921e: failure to reset causes network drop

mt7921e: failure to reset causes network drop

[moosager]

Hello,
there is an issue with the mt7291e that causes the network to drop at random, 
with dmesg outputting repeatedly:
kernel: mt7921e 0000:62:00.0: Timeout for driver own
kernel: mt7921e 0000:62:00.0: driver own failed

Other effects are the system becoming generally unresponsive, kernel panics 
(reporting "Fatal exception in interrupt"), and the system instantly rebooting. 
It also has a tendency to happen again on every subsequent reboot.
More reports of users' experiences are available at [1].

This script lets you reproduce the issue:
#!/bin/sh
echo 0x7c060010 > /sys/kernel/debug/ieee80211/phy0/mt76/regidx
while true; do echo 0xffffffff > /sys/kernel/debug/ieee80211/phy0/mt76/regval ; done

I had previously investigated the code and have some potential insight: during 
normal usage, the function __mt792xe_mcu_drv_pmctrl writes to a register 
like this:
mt76_wr(dev, MT_CONN_ON_LPCTL, PCIE_LPCR_HOST_CLR_OWN);

and it expects to find 0x00000004 (which is PCIE_LPCR_HOST_OWN_SYNC). Instead, 
when the issue happens, it finds 0xffffffff, which does not change even after 
the driver attempts to write to it.

In addition, the failure of __mt792xe_mcu_drv_pmctrl returns -5 as an error 
code; this is not checked by the caller, mt7921e_mac_reset, which calls 
mt792xe_mcu_drv_pmctrl without checking its return value.
 
I have also found some potentially helpful patches at [2]; however, applying 
them did not fix it, and my best attempts at adapting the proposed code paths to 
be triggered in mt7921e_mac_reset have not fixed it either.

Here is my firmware version reported in dmesg:

[   15.848101] mt7921e 0000:62:00.0: enabling device (0000 -> 0002)
[   15.849369] mt7921e 0000:62:00.0: disabling ASPM  L1
[   15.865381] mt7921e 0000:62:00.0: ASIC revision: 79220010
[   15.958433] mt7921e 0000:62:00.0: HW/SW Version: 0x8a108a10, Build Time: 20260605203307a
[   16.352504] mt7921e 0000:62:00.0: WM Firmware Version: ____000000, Build Time: 20260605203411

It has also been happening at least since the firmware with HW/SW build time 
20251118163143a and WM firmware build time 20251118163234, which is when I got 
my laptop with this Wi-Fi chip.

Note: the issue happens whether ASPM is on or off.
The issue happens on my build of the vanilla 7.2.0-rc4 kernel, as it has 
been happening on every past kernel version.

I would like some guidance as to how I could debug the issue further, though 
ultimately the problem is likely in the firmware. It would be very helpful to 
have this fixed, as it currently makes my laptop almost unusable, and I know I'm 
not the only user having this issue.

[1] https://bugzilla.kernel.org/show_bug.cgi?id=220353
[2] https://lore.kernel.org/linux-mediatek/20260506070458.3096180-1-jb.tsai@mediatek.com/