Hi Sadeep,
On Thursday, 16 November 2023 at 16:56 (+0800), Sadeep Madurange wrote:
The AP is using frequency 5240MHz. This frequency is disabled on the
T490 according to the output of iw list | grep -A 15 Frequencies:.
Great, so we know the problem!
The ArchWiki page I linked earlier [1] has some advice on checking
whether the firmware of your laptop is enforcing a hardcoded regulatory
domain. This might be the case if the laptop's hardware was originally
intended for another country.
I am in Singapore, and according to
https://en.wikipedia.org/wiki/List_of_WLAN_channels, 5240MHz can be
used here without restrictions. Additionally, I don't understand why
this kicked in this week while working fine for about 2 months now.
Probably the access point changed its frequency. If you can configure
the access point, you can set its channel to something supported.
Jaron
[1]: https://wiki.archlinux.org/title/Network_configuration/Wireless#Respecting_the_regulatory_domain
