Automatically fetch the GNSS assistance data from the Web
to heavily reduce the time to acquire a GNSS lock by uploading
the assistance data to the modem.
This feature is optional and can be disabled in the configuration
as people may prefer to not download the assistance data from
the Quectel/Qualcomm servers.
Also configure the GNSS engine to optimize the performance
and power consumption.
In some internal discussions between me,
the ModemManager maintainer and a Quectel engineer,
the URC cache we use is unnecessary.
I did some testing and removed the URC cache
from the configs and it works reliable without affecting
the functionality.
This brings the power on sequence in line with the EG25-G Hardware Design
datasheet, which states we need to wait at least 30 ms after VBAT becomes stable
before pulling PWRKEY low (first action of the power on sequene).
After this change the sequence becomes as follows:
- Set RESET_N high
- Wait 60 ms (double 30 ms)
- Execute PWRKEY sequence
60 ms was choosen because we don't know when VBAT becomes stable, but it should
be much less than an additional 30 ms. Empirical evidence suggests PinePhone
units with a healthy battery do not see serious side effects from not doing
this, while the modem will fail to boot and/or throw random errors on boot with
a worn out battery.
dquote> When using a custom kernel, if this setting is set to 'usbat' only, no RING urc is reported on any interface. Changing QURCCFG to 'all' makes the modem report RINGs on all supported interfaces, making receiving calls possible when using a custom firmware
