mt7915: invalid airtime channel utilization for dap-x1860

[maurerle]

For the target ramips-mt7621, the device dlink-dap-x1860 does not show airtime channel utilization in current main.

After bisecting this to a specific commit, I found that the cause of this is in this commit:

b4a9174

Further information on this issue is provided in the gluon-issue-tracker at:
freifunk-gluon/gluon#3338

Solution

Currently, there is no other solution than to use the mt76 commit prior to the mentioned one.

If there is anything I can do to help fix this, I will - though I did not quite understand what goes wrong on this specific device and did not understand the code well enough.

The WSM20 and COVR-X1860 are not affected though and this issue does not influence general wireless clients quality

[maurerle]

Sometimes after 3h or after 36 hours, this bug fixes itself, magically:

Eventually the device calibrates itself..?
All the 50 DAP-X1860 devices had this problem and did stop having it after a few days.