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+--- Thread: Powering the modem after turning off the smartphone (/showthread.php?tid=15691)
Powering the modem after turning off the smartphone - Mikoduso - 01-05-2022
Hello.
I don't understand well in block diagrams, but looking at "PinePhone v1.2b Released Schematic.pdf" I see that the modem is connected directly to the battery.
Will the modem have power after turning off the smartphone?
RE: Powering the modem after turning off the smartphone - lot378 - 01-05-2022
The modem contains a single-core ARM CPU running a Linux-like OS.
The OS on the phone needs to task the OS on the modem to shutdown, when the OS on the phone is being shutdown.
In both OS, power is connected to the phone hardware (other than modem) and modem hardware even when both are shutdown. If both OS are shutdown, then neither is using power or using the battery or causing the battery to drain. There have been cases when the phone OS has shutdown while leaving the modem OS running causing the battery to drain.
RE: Powering the modem after turning off the smartphone - Mikoduso - 01-05-2022
(01-05-2022, 07:29 AM)lot378 Wrote: The OS on the phone needs to task the OS on the modem to shutdown, when the OS on the phone is being shutdown.Thank you. And where can you read about these requirements. Is it from some document?
RE: Powering the modem after turning off the smartphone - grwlf - 02-04-2022
(01-05-2022, 01:15 PM)Mikoduso Wrote:(01-05-2022, 07:29 AM)lot378 Wrote: The OS on the phone needs to task the OS on the modem to shutdown, when the OS on the phone is being shutdown.Thank you. And where can you read about these requirements. Is it from some document?
I studied the suspend/resume protocol of the modem recently. It is not about powering down as you asked, but the links I collected may be useful for you.
I think I saw the related code in both Modem-power kernel driver and eg25-manager sources.
https://github.com/NixOS/mobile-nixos/issues/348#issuecomment-1028385001