PinePhone modem keeps "disappearing"

[zetabeta]

if the modem goes every 5 minutes then i start to suspect some failure, maybe in modem chip, or modem's software (firmware), or possible connection in mainboard.

modem has its own firmware, which might have become corrupted.

i think you should install firmware again, either stock or half-free sdk. however, i don't rule out that modem chip is faulty.

https://github.com/Biktorgj/quectel_eg25_recovery

https://github.com/the-modem-distro/pinephone_modem_sdk

however, i recommend setting modem's powersaving "on" in both stock rom and half-free sdk. following recommends it only for sdk.

https://github.com/the-modem-distro/pinephone_modem_sdk/blob/kirkstone/docs/SETTINGS.md

i have this following copy-paste to prevent some issues.

Code:

# example file location: /lib/udev/rules.d/98-prevent-bugs.rules

# prevent powersaving flipping frames bug
KERNEL=="1c40000.gpu", SUBSYSTEM=="platform", DRIVER=="lima", ATTR{power/autosuspend_delay_ms}="-1"
KERNEL=="1c40000.gpu", SUBSYSTEM=="platform", DRIVER=="lima", ATTR{power/control}="on"

# prevent frequency change flipping frames bug
KERNEL=="1c40000.gpu", SUBSYSTEM=="devfreq", ATTR{min_freq}="432000000"
KERNEL=="1c40000.gpu", SUBSYSTEM=="devfreq", ATTR{max_freq}="432000000"

# prevent modem disappearings
ACTION!="add", GOTO="eg25_end-edit"
SUBSYSTEM!="usb", GOTO="eg25_end-edit"
DRIVER!="usb", GOTO="eg25_end-edit"
ENV{DEVTYPE}!="usb_device", GOTO="eg25_end-edit"

# NOT Default attributes values
ATTRS{idVendor}=="2c7c", ATTRS{idProduct}=="0125", ATTR{power/control}="on"
ATTRS{idVendor}=="2c7c", ATTRS{idProduct}=="0125", ATTR{power/autosuspend_delay_ms}="3000"
ATTRS{idVendor}=="2c7c", ATTRS{idProduct}=="0125", ATTR{power/wakeup}="enabled"
ATTRS{idVendor}=="2c7c", ATTRS{idProduct}=="0125", ATTR{power/persist}="0"

LABEL="eg25_end-edit"
# end of modem disappearings

i have started to think there is some bad quality in cpu-gpu soc. mostly related to powersaving. some hardware related functions work randomly and unreliably. powersaving is issue for both gpu and modem, is that a coincidence.