Quote
ntware - 2020-12-18 12:45 PM
Anyway, if I can offer you any suggestion, I would say stay away from the Chinese ARM chips, like the H3, H4, Rockchip, Mediatek etc. They are cheap, but don’t get temped by that. I had a lot of headache with them when I was building an ARM device for work. As you probably know now, support for them is pretty much unexistent. These chips were made to run Android, not Linux (even though Android runs on Linux kernel, they are very different). Therefore, you will only find some sort of support to run Android, and still it will be very crappy. It is not worth the effort.
My experience certainly backs this up - both of the non-Pi ARM boards I've tried
(Pine A64-LTS and A64-Olinuxino
) are based on the Allwinner A64 - For both there has been a lot of effort put into getting recent mainline kernels working on them, but in both cases so much of the hardware isn't working, or is working poorly that they basically don't work for my purposes. Annoying as I know that this was originally a tablet SoC so it ought to be able to handle LCD output, battery management etc. - Again as you mention this would have course have been on Android, and probably only properly supported by the chip manufacturer for one specific
(and now badly out of date
) kernel version.
Quote
ntware - 2020-12-18 12:45 PM
To create a truly ARM board, you will need to go to a more respected chip manufacturer, like Freescale/NXP or even Broadcom that manufactures the RPi ARM SoC, is closer to the cheaper spectrum, but is still very sturdy and well supported. I honestly think you should insist a bit more on the Pi, especially the Compute Module 4, if you want to make it more professional. That’s a great hardware for a very low price. Going to x86 will give you a lot of problems on power consumption. Peak current on x86 is very high, you will have to build a super nice power supply/battery to hold that. ARM is the way to go for mobile devices.
Everything I've read about the different architectures indicates that performance-per-watt is far better on ARM - my very simple tests on the Atom-based Lattepanda show it drawing noticeably more power than the ARM boards under load
(again, as you've said
). My problem, at least so far, has been that I couldn't get any of the boards' power consumption sufficiently low when idling / sleeping - The 'instant on' and long standby times was one of things I most liked about HPCs so I would love to get at the very least to a few days in standby.
In the case of the A64-based boards I couldn't achieve this because although the hardware was capable, none of the OSes I've tried could put them in a proper 'suspend' mode. In the case of the Pi it's basically because the SoC has no sleep / suspend capability as it's derived from chips intended for set top boxes rather than portable devices
(as I understand it
). I don't know if it would be possible to implement this kind of function outside of the SoC itself
(say on some sort of carrier board for the Compute Module
) but I honestly wouldn't know where to start with trying to do this myself.
Despite what I've just said I am a fan of the Pi, and the Pi-based version of my HPC was definitely my favourite so far. Given that I never got more than 'suspend-to-idle' out of the other two boards it wasn't really much worse in 'standby' power consumption either. This may well have got better in the year or so since I've played with the Pi - The ongoing support by the Pi team has been generally excellent.
I enquired with the Hackboard team about the onboard battery charging, and they said they had designed it with DIY laptop / tablet type applications in mind so I would hope at least their power circuitry can deal with the demand from the CPU - I didn't ask about power consumption but I can probably roughly estimate this from specs of laptops using the same CPU.
I'm probably still leaning more towards at least trying out one of the x86 boards, however I'm tempted now to try both - 'Order' the Hackboard 2 now and while I'm waiting for it to arrive, build a basic machine out of the Pi 4 again
(I still have most of the components
). Maybe even see what I can do with a Compute Module and carrier board. Then I can compare the two properly.
Thank you for your input - It's very much appreciated! I hope I don't come across as defensive over my decision to try an x86 board, I'm just trying to explain my reasoning here
(a lot of which is based on the limits of my abilities
) and I'm very happy to be corrected on anything I've got wrong. The only part of this project I could claim to be any sort of expert on is the mechanical design of the case, and even then my background is in very different machines.