[elementarythree]

I got this device last week because I always wanted to have an portable eInk computer I can run stuff like emacs on, and this is as close as a ready made solution that exists. The eReader and scribbling/drawing part of course is also interesting, but I gotta admit I got this mostly for Termux and Linux userland after having a lot of fun with that on an rooted LineageOS smartphone. After reading some of the threads here, I don't think I'm the only one.

It'd be nice if we could collect some snippets of knowledge in this thread to make the device more into a computer experience, a bit for advanced Linux users maybe.

To start things off, I have a command to get a rough estimation how fast a device is, by letting it calculate PI to 5000 digits:

time echo "scale=5000; a(1)*4" | bc -l

I know it's not incredibly accurate but it's a nice real life test to get an idea in what ballpark to put a CPU in and runs on almost everything that provides the tools and also gives you a difference between real time (how long the command ran in clock-time) and user time (how much the CPU actually spent on the process) no matter how busy the system is elsewhere. When a device does nothing or almost nothing real time and user time are usually very close. When running this command on the Boox Max2 I got a crazy discrepancy: while the device only took ~57 seconds to calculate Pi (which is quite ok for a mobile device, for comparsion, my i7 5820k needs about 10 seconds) it took about 25 minutes (!!!) of real time to actually finish the process.

After rooting the tablet and rummaging around, I found the interactive CPU governor was to blame, which was set by the Onyx engineer to very aggressive values and keeping the speed of the CPUs low, probably for powersaving purposes. Setting the device to the more standard ondemand governor removed the bizarre delay in finishing that task and also made my bluetooth keyboard and the general user interface *a lot* more responsive, basically eliminating the need to double tap things because the device failed to register the first tap, which I'm sure a lot of people are familiar with.

So that's a neat trick. I have no idea which influence it has on battery life, it does not seem to be dramatic though so far as ondemand also clocks the CPUs down when nothing is happening. As the device is thin, made of plastic and weights almost nothing, I am not sure if it couldn't overheat when at this setting (which might also be a reason for the aggressive setting to begin with) so use at your own risk. I haven't noticed any heat problems with normal usage either though. If you are not that familiar with the command line, there are also apps to change these kernel settings. You will need root though.

On my phone I have battery charging disabled when it is connected to usb, which is great for the battery as USB provides enough energy to keep my entire phone running. I'm trying to find a similar function with the charging circuit of the Max2 (would be nice in order to help the battery when used as a screen) but I'm not even sure the charging circuit is capable of it, or the driver exposes such a setting, at least I couldn't find anything so far. Gotta admit, the screen is very nice but everything around it is kinda meh, especially for the price. We'll see.

I'd like to hear about your bits of wisdom!