[LEDE-DEV] iw / ath9k / mediatek / strange values for 'signal'

[Bastian Bittorf]

we use the signal reported from 'iw' for some actions
and I can see them beeing inconsistent or maybe even
wrong calculated (strange values are marked)

root at box:~ iw dev wlan0-1 station get 60:5b:b4:9a:e4:8b
Station 60:5b:b4:9a:e4:8b (on wlan0-1)
        inactive time:  10 ms
        rx bytes:       820080
        rx packets:     6018
        tx bytes:       13855366
        tx packets:     9884
        tx retries:     1696
        tx failed:      0
***     signal:         -4 [-59, -59, -54] dBm
        signal avg:     -53 [-57, -57, -52] dBm
        tx bitrate:     58.5 MBit/s MCS 6
        rx bitrate:     130.0 MBit/s MCS 15
        expected throughput:    30.120Mbps
        authorized:     yes
        authenticated:  yes
        preamble:       short
        WMM/WME:        yes
        MFP:            no
        TDLS peer:      no
        connected time: 161 seconds

root at box:~ iw dev wlan0-1 station get 60:5b:b4:9a:e4:8b
Station 60:5b:b4:9a:e4:8b (on wlan0-1)
        inactive time:  70 ms
        rx bytes:       1262941
        rx packets:     8861
        tx bytes:       19504789
        tx packets:     14266
        tx retries:     2572
        tx failed:      0
***     signal:         -95 [-58, -58, -53] dBm
        signal avg:     -55 [-56, -57, -52] dBm
        tx bitrate:     78.0 MBit/s MCS 12
        rx bitrate:     117.0 MBit/s MCS 14
        expected throughput:    35.613Mbps
        authorized:     yes
        authenticated:  yes
        preamble:       short
        WMM/WME:        yes
        MFP:            no
        TDLS peer:      no
        connected time: 292 seconds

root at box:~ iw dev wlan0-1 station get 60:5b:b4:9a:e4:8b
Station 60:5b:b4:9a:e4:8b (on wlan0-1)
        inactive time:  20 ms
        rx bytes:       2460373
        rx packets:     9789
        tx bytes:       19619950
        tx packets:     14761
        tx retries:     2599
        tx failed:      0
***     signal:         -20 [-59, -58, -53] dBm
        signal avg:     -85 [-57, -58, -53] dBm
        tx bitrate:     117.0 MBit/s MCS 14
        rx bitrate:     52.0 MBit/s MCS 11
        expected throughput:    42.296Mbps
        authorized:     yes
        authenticated:  yes
        preamble:       short
        WMM/WME:        yes
        MFP:            no
        TDLS peer:      no
        connected time: 313 seconds

beside these 3 shots, i can see also values for signal of:
"8" (positive!) and "-126"...

i can see this with different versions of OpenWRT and LEDE
and with ath9k and Mediathek. What can I do for debugging this
better? The connected station is *not* moving.

bye, bastian