[PATCH] nas: add support for Set System Selection Preference radio interface acquisition order

Aleksander Morgado aleksander at aleksander.es
Thu Feb 16 21:10:50 UTC 2017

On Thu, Feb 16, 2017 at 10:01 PM, Dan Williams <dcbw at redhat.com> wrote:
> Yeah, I also tried setting both the "Mode Pref" and the "Acq Order
> list" at the same time and my 7700 didn't like that much.  Not sure
> what's really going on.
> One more thing to try:  can you make it lock to a specific technology?
> eg "=umts" or "=lte"?  Maybe that's a way to be able to lock to 3G or
> 4G.

That works, yes; but that already worked before didn't it? i.e. in
ModemManager you could select "lte" *capability* and that would use
SSP to set "lte" only; or you could select "gsm-umts" capability and
then we would allow 2G+3G with WCDMA acquisition order preference
changes (and different allowed/preferred mode combinations exposed).
That was the special case we had to handle with "lte" only vs
"gsm-umts" only; in the former there would only be a single "4g" mode
allowed "none" preferred combination; while in the latter we would
have "2g,3g" allowed with 3 preferred combinations: "2g", "3g" and
"any". For the "lte|gsm-umts" capability, there was no way to "prefer
lte" or "prefer umts" or "prefer gsm", which is why no such
combinations were added for allowed/preferred modes.

$ sudo qmicli -d /dev/cdc-wdm1 --nas-set-system-selection-preference="lte"

$ sudo qmicli -d /dev/cdc-wdm1 --nas-get-signal-info
[/dev/cdc-wdm1] Successfully got signal info
RSSI: '-67 dBm'
RSRQ: '-8 dB'
RSRP: '-97 dBm'
SNR: '18,0 dB'

$ sudo qmicli -d /dev/cdc-wdm1 --nas-set-system-selection-preference="umts"

$ sudo qmicli -d /dev/cdc-wdm1 --nas-get-signal-info
[/dev/cdc-wdm1] Successfully got signal info
RSSI: '-77 dBm'
ECIO: '-2,5 dBm'

(single tech now works again; it didn't with the original patch)


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