Quite plain question:
Once auto-rotation is activated, both the default portrait mode and landscape view are possible. What doesn’t seem possible is portrait mode upside-down.
I wonder if this is for hardware reasons in the gyroscope or if it’s just programmed like that?
The background of my question is that I was thinking allowing upside down portrait mode could be a good workaround for phones with a defect primary microphone (assuming the dialer is ready for portrait mode upside-down).
P.S.: On second thought, the workaround idea is probably not that feasible – the rear/side speaker doesn’t exactly allow for confidential phone conversations. Nevertheless I would be interested if anyone could answer the basic question.