Re: Regression: mt7921e unable to change power state from d3cold to d0 - 6.12.x broken, past LTS 6.6.x works

[Sergio Callegari <sergio.callegari@gmail.com>]

Hi,

On 20/03/2025 00:54, Greg KH wrote:
> On Wed, Mar 19, 2025 at 08:38:52PM +0100, Sergio Callegari wrote:
>> There is a nasty regression wrt mt7921e in the last LTS series (6.12). If
>> your computer crashes or fails to get out of hibernation, then at the next
>> boot the mt7921e wifi does not work, with dmesg reporting that it is unable
>> to change power state from d3cold to d0.
>>
>> The issue is nasty, because rebooting won't help.
> 
> Can you do a 'git bisect' to track down the issue?  Also, maybe letting
> the network driver authors know about this would be good.

Bisecting is extra painful, because the issue seems to systematically 
happen only when freezing on restore from hibernation, which in turn 
seems to happen only when I get in hibernation through the 
suspend-then-hibernate path. Because this is my main machine, I need to 
desperately try to avoid these freezes/crashes, since I am afraid of 
data loss (I have already broken a filesystem once this way, and I don't 
want to repeat the experience).

However, in the meantime I have found confirmation for the issue. See:

- https://bbs.archlinux.org/viewtopic.php?id=301985
- https://forum.manjaro.org/t/wi-fi-mt7921e-stopped-working/175867

I would not totally trust the second link where it says that 6.12.4 was OK.

The general wisdom seems to be that with recent kernels you need to 
disable ASPM for mt7921e. Now I wonder if 6.6 was maybe not activating 
aspm for that device...

There is also:

- https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2059744

 From which I get that the problem was already present in 6.8 and that, 
removing the mt7921e kernel module before shutdown and suspend may work 
around the issue.

Sergio




> 
> thanks,
> 
> greg k-h