Re: is my phone ON or is it OFF?

On 5/2/24 17:59, Carlos E.R. wrote:

On 2024-05-02 13:43, bad💽sector wrote:

On 5/2/24 02:17, Carlos E.R. wrote:

On 2024-04-27 11:16, Theo wrote:

Jörg Lorenz <hugybear@gmx.net> wrote:

On 25.04.24 15:55, Frank Slootweg wrote:

Jeff Layman <Jeff@invalid.invalid> wrote: [...]

 ...
 

Bullshit! The OS is not booted when the Android is turned off.

>
AIUI it is, kind of.  When you plug in the charger with the phone
 off, the phone starts.  The bootloader then launches the Android
kernel with the flag androidboot.mode=charger
>
Instead of doing the full Android boot, that causes the kernel to
 launch a charger UI application that shows your battery
percentage on the screen or an animation (which comes from files
on your OS partition).  The charger app doesn't allow you to
otherwise interact with the phone and other services like the
radios aren't running, but the SoC is booted and running software. The SoC is also doing standard power management, ie the
charging process here likely looks very similar to charging when
the phone is turned on (because it is, in essence).
>
The full OS services are not running, but the Android kernel and
the charger app is.
>
Theo (usual caveats: my understanding may be out of date,
different vendors may do their own thing, etc)

>
>
Hum!  That's the best explanation I have seen so far. Thank you. It
 explains things.

>
>
Like your compuer, it's sleeping with one ear (and maybe eye) open.

 Low power processors can do things like switch off circuitry, or stop
processing completely till some external event happens.

Like a suspersensitive motion sensor or passive mic? I don't wanna get into that discussion, it's a whole another can of worms :-)

This is used in circuitry that runs on batteries for months, like the speed meter of a bicycle. If the wheel doesn't turn, the processor and everything sleeps, except the turn counter.
 Well, this is the same idea: boot a different image that only powers up what it needs in order to track battery power and charging.
 Doable.