bug report: High CPU utilisation with auto-rotate on (Z5 compact)

[stevo125]

 Hi,

I've tried monitoring CPU frequency with auto rotate on and off and noticed that with auto-rotate on if that phone is being moved about then the CPU cores all ramp up quite a bit.

To re-create:

• use on-screen cpu frequency monitor
• *shake* the phone in front of you whilst watching CPU frequency
• with phone locked portrait I have 4 small + 1 big at 384 Mhz.
• with auto rotate I get 4 small cores at 1500 and 2 big core at 1.5-1.8

The only record I can find of this kind of bug online is some entries in Google's bug databases for the Nexus S back in 2013-2014.

What does this mean? well, assuming you don't have rock-steady hands, or perhaps you want to use your phone in a dash-clamp in the car, this random CPU spiking with drain the battery and heat up the phone for no reason!

I've been able to get a notable increase in battery and reduced heat output of my phone by leaving rotate off unless I really need it, but this is clearly an issue that needs to resolved.

[Uliwooly]

@stevo125

Could you test this on safe mode ? 

[stevo125]

unfortunately I cannot test in safe mode as there is no way of checking cpu frequency in this mode.

I have however confirmed this issue on a completely fresh from the box z5 compact that arrived as exchange unit. This unit is still on the old 32.0.A.4.11 firmware so this issue is clearly not a new bug introduced with the 32.0.A.6.xx update.

[Uliwooly · Accepted solution]

@stevo125

I'll try to escalate this 

[stevo125]

thank you.
hope something can be done with it.
looks like an old android bug dating back to icecream-sandwich. very stange to see it now.
I've checked that other features that use the accelerometer don't trigger this issue (e.g smart backlight, diagnostic tests), seems to be just auto rotate.