My Samsung Galaxy S7 (SM-G930F, Android 8.0.0) has started locking up -
sometimes the screen just freezes, sometimes I also get minor screen
corruption. The only remedy that I can find is to hold the power switch for
about 20 seconds to force a restart, because the phone then becomes
completely unresponsive to touch screen, a brief press of the power switch
(which would normally blank the screen) or to either of the volume buttons
(which would normally display the volume slider).

It started misbehaving about 1-2 weeks ago; until then I'd never had any
problem.

It *may* happen after I run Dolphin browser (V12.2.9), but since Dolphin is
configured to be my default browser, it gets used so often that this may be
a red herring.

What is the best way to troubleshoot what is causing the problem? Does
Android have any log of what causes lock-ups, or any core-dump files?

At present it is happening about 10 times a day. The phone always remains OK
if is left in the blank-screen, no-apps-running state (eg overnight) so it's
not a background task that is causing it, but apparently some foreground
application.

Occasionally I've have the problem twice in succession - for example,
long-press the power switch to force a reboot; when the 9-dot pattern
appears on the lock screen, I start to draw my pattern and the screen locks
part-way through. But that is rare: almost always the phone signs in and
displays the home screen and lasts OK until I start to use it (browsing,
reading emails).

Does Android have a log of which apps have been automatically updated from
Play Store (either completely automatically or after seeking permission) and
when those updates occurred? Maybe that would point the finger at what has
updated in the past couple of weeks.

I'm not aware of having explicitly installed a brand new app that I didn't
have before the problem, and unfortunately I can't remember all the apps
which have auto-updated after asking permission in Play Store.

"NY" <me@privacy.invalid> wrote in message
news:tukmft$33gaj$1@dont-email.me...
> My Samsung Galaxy S7 (SM-G930F, Android 8.0.0) has started locking up -
> sometimes the screen just freezes, sometimes I also get minor screen
> corruption. The only remedy that I can find is to hold the power switch
> for about 20 seconds to force a restart, because the phone then becomes
> completely unresponsive to touch screen, a brief press of the power switch
> (which would normally blank the screen) or to either of the volume buttons
> (which would normally display the volume slider).

One slight update: it's not necessary to hold down the power button to force
a reboot when the phone locks. It reboots spontaneously after a delay of
about 30 seconds.

One other strange thing. The Device Maintenance | Battery | Battery Usage
graph shows long gaps/discontinuities. I can understand very brief ones
while the phone reboots, but in the following graph

https://i.postimg.cc/6Qk9kscF/Screenshot-20230312-160642-Settings.jpg

there's a gap of about an hour during which time the battery discharged a
bit but the phone was *apparently* not on. The shorter breaks are probably
when the phone locked and rebooted.

The discrepancy between the 5h 13m ago on the graph and the "Recent Battery
Usage = 3h 42m" is probably due to the fact that the phone was disconnected
from mains from the start of the graph until about 3/4 of the way across,
while the line is going downwards, and then the "Recent Battery Usage" timer
stopped when I plugged the phone into the mains and recharged the battery
from 50% to 100%.

Any suggestions as to what could have started happening and how to gather
diagnostic evidence?