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2021–10–15: Pinephone Pro – A Quick Review

I received Pinephone Pro (2021–05–11 batch) at the end of August. Here's a summary of my experiences with it so far.

Obligatory boot video :)

U-Boot is terribly slow in the default configuration, so I didn't even try it. But I ported Levinboot to PPP and here's Levinboot booting up the Arch Linux ARM from eMMC: (Levinboot is on SD card and the payload is on eMMC)

Whoa, that was fast! 6.15s to desktop. Exactly just like the Pinebook Pro boot times. ;) All that is thanks to CrystalGamma, and his work on Levinboot. :)

Here's a serial console view of Levinboot starting up on Pinephone Pro.

Power consumption

It's a portable mobile device, so I guess power consumption is what people will care about a lot. It has two aspects: how long it will run on battery, and how much it will heat up under load.

I have a nice setup for measuring the load at 1000 samples per second via this fake battery setup I made for original Pinephone:

Pinephone Pro came with Android factory image, that I used to get some initial numbers to compare against in the future. This image most likely doesn't limit the maximum CPU frequency, so the peak power consumption is quite high, due to that.

So this basically says that heavy use will drain the battery in about 1.5h, idling with screen on in aboutu 3–4h, and the phone will become unstable near the lower end of the capacity, because I don't think the single cell battery will sustain high enough voltage with load peaks of 10W or more near the lower end of the capacity. (that would be 3A+) battery in Pinebook Pro probably fares better at this, due to lower internal resistance. CPU throttling based on remainging capacity will be needed to control this issue.

When suspended to RAM (standby) the phone will last for about 2 and half days with the Rockchip's TF-A blob. This is worse than Pinephone, which has power consumption in suspend around 60 mW (2.5× better).

Once I had Arch Linux working on the phone, I also measured the power consumption on mainline Linux + mainline TF-A.

I used the default backlight brightness of 2000 or so, wifi was turned on, and I varried CPU frequency limits (cpupower frequency-set --freq $FREQ) and loaded the CPU cores with openssl speed -multi $N.

Baseline idling with brightness set to kernel default and 1.42GHz limit was 3.1W.

6    408 MHz    3.5 W
6    600 MHz    3.8 W
6    816 MHz    4.2 W
6   1.01 GHz    5.5 W
6   1.20 GHz    5.5 W
6   1.42 GHz    6.9 W
2   1.42 GHz    5.1 W
1   1.42 GHz    4.1 W

N = 1 (loading one performance core to max)
N = 2 (loading two performance cores to max)
N = 6 (loading all cores)

Backlight brightness vs power:

100     2.8 W  (almost not visible)
2000    3.0 W
3000    3.4 W
3500    3.7 W
4000    4.2 W
4095    4.3 W  (max)

The scale is non-linear.

So at full brightness/full CPU load at 1.42GHz, the phone will consume about 8.3W. This test is without the GPU doing anything. GPU will probably add something, too.

Some board photos

Some things I noticed:

What works

I did not yet test the rest.

Kernel status

I'd like to add cameras to DT, but that will need a working 5.15 kernel (because it has support for multiple cameras). Linux 5.15 is currently not booting on Pinephon Pro. It hangs mid-boot possibly on some issue related to RCU.

Other than that, non-mainlined drivers for the PMIC battery and charger support are needed.

The rest of the support is very similar to Pinebook Pro, ie. non-working convergence in mainline Linux.

Closing words

Pinephone Pro is basically Pinebook Pro with more useful PMIC, modem, cameras, and a better supported wifi chip (cypress supported cyw43455 is more open than broadcom supported brcm43456 in PBP) in a much smaller form factor.

Performance is thus much better than the original Pinephone, but the power consumption is higher too. Baseline power consumption with normal backlight brightness and screen turned on is ~2.8–3W. Doing something in the browser or just moving the mouse around rises the power consumption to ~5W. This was tested in sway, with GPU acceleration turned on, and only one CPU core enabled.

That's not a huge problem for Pinebook Pro with its 36Wh battery (4–7h runtime on a notebook is nice) 2–3h runtime with screen on, on a phone, is a problem. It will be a nice mini-notebook with a pinephone keyboard, though. :)