Brainux freezes at display manager/login: on PW-A9100

It boots to some sort of non-graphical text display manager called ly. Then the cursor stops flashing when I press any key and the Brain is totally locked. I tried disabling ly but the same thing happens at the normal login: prompt.

I know there is nothing wrong with my SD card because I tested it in a Brain model PW-SH3 and it boots to Xorg fine. There's no clue in /var/log about what happened and no error message. The only button that will do anything is the reset button.


According to the Brainux wiki PW-A9100 is supported. Any Brainux experts know what might be wrong?

Is PW-A9100 the type where the device keyboard is enabled?
It says on the Brainux wiki that you need a OTG cable on some models to type with the keyboard. (Connect keyboard via OTG).

Also, make sure you have the right version of the .zip file containing the Brainux.
https://github.com/brain-hackers/buildbrain/releases

-stingraze

An user raised a similar issue in Brain Hackers Discord two weeks ago for PW-A7400, and developers are trying to find out the cause and fix it. Might be related as PW-A7400 and PW-A9100 are released in the same year, which suggests they share the similar hardware.

(Note that the Brainux keyboard driver is written from scratch by Brain Hackers, analyzing the hardware as far as probing the electronic circuit in Sharp Brain with an oscilloscope. So there are still some issues to be fixed.)

I think you don't need the uboot stuff anymore, the /boot partition in the sd image contains it all the dtb and genXX.bin files. When you start Linux Loader from WinCE, I think it picks for you. Hmm, unless it is getting it wrong and nobody has noticed because they all own PW-SHX models.... When I get home, I'll try deleting all but /loader/gen2.bin, /nk/edna3exe.bin and /ima28-pwa-7200.dtb. I don't think I have an OTG wire, but then it has been a while and I've got a lot of junk....

There is a hardware keyboard on A9100 and an LCD input area, just like A7200. Hardware appears to be the same as A7200. Just from playing around with 9100, it looks like it has newer firmware than 7200, more colorful UI.

I think the documentation is a little out of date...or something: I tried building the kernel but it failed. I was however able to build the brainux filesystem and add more packages: abiword, gnumeric, xmahjongg, xdemineur, xsol, nethack, slashem, gnuplot matchbox, windowmaker, fvwm and a few emulators. Rather than deal with network cat-herding, I think this is simpler: after make brainux, from the buildbrain/brainux I just copied the usr, etc, var folder over to the sd card on the PW-SH3. Wow! It's great to have real Linux on a handheld PC again.

Too bad there is no way to suspend? I wonder....

I have not thoroughly examined the /sys filesystem but I have discovered that you can control backlight on PW-SH3:



can be edited with nano if you are root. The default of 7 is too bright. 4 is just right for me.

will not work even if you are root. I think there is some udev skullduggery involved if you want to be able to do it this way....


Also, the SD image only consists of 2 partitions FAT32 boot and EXT4 rootfs. There is no reason the boot partition has to be tiny. I have tested as big as 8 GB and Linux Loader doesn't care: this means you can effectively dual boot a single SD card by copying all your WinCE stuff into /boot in addition to Linux Loader. WinCE will ignore the second partition. So finally, running linux on an HPC is not a total hair shirt: you don't have to constantly backup/restore to switch WinCE<-->Linux and there is no risk of a brick in any case.





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Looks like it's under development. I expect it to take much time as it requires a proper implementation of power management.

https://github.com/brain-hackers/linux-brain/tree/suspend

To add packages, this way is available too: Install qemu-user-static on your desktop Linux machine, chroot into the rootfs on the SD card, and invoke apt install there.

Windows Mobile devices can be very picky about SD cards and the formatting of SD cards.

Formatting a SD card with a Windows laptop is not ideal; formatting with a high-quality camera, PDA has better luck IME.

This is unlikely to be the issue but is so easy it is worth trying different cards / formatting.

Update on this: The dev bought and tested PW-A9100 and confirmed that the keyboard works on PW-A9100, here is what he did in the testing process. (translated)



Although balenaEtcher runs on Linux too, you can use the "dd" command instead if you prefer.

You might have followed a wrong (or obsolete) guide on setting up Brainux, the current official way is as easy as this; no manual compilation or such involved. The latest guide on setting up Brainux is here: https://wiki.brainux.org/beginners/get-started/

Edited by watamario15 2024-01-07 2:08 PM

I will try a fresh install on a new Onn-branded card with PW-A9100. Strange that it works ok on PW-SH3. I'm using a low quality 64GB no-name card so it could be faulty.

For now, I am just playing with Brainux on PW-SH3. The keyboard layout is more obvious on SH3 and I can put up with keys that feel mushy. Key combinations are unresponsive and then get stuck repeating when they do work. Commonly used symbols at command line . / ~ and : (for vim) are not easy to type. It's not a problem with the default terminal; you get the same behavior in xterm and rxvt. (These keys don't stick in WinCE so it is not a defective keyboard.)

btw, is there some file in /sys which will tell battery voltage or percentage?

I'd bet it's not implemented yet, at least as of August 2022 it wasn't. It involves the implementation of power management stuff (as always, from scratch, reading the electronic signals).

If you are still facing the same issue, might try replacing imx28-pwa7200.dtb with this one?
https://cdn.discordapp.com/attachments/1187668746710568990/1196140474294075412/imx28-pwa7200.dtb

This is an experimental file crafted specifically for PW-A7400 (despite its name) and not meant to be used for PW-A9100, but just a possibility.

I was doing some digging on GitHub for the various projects for the Brain and some of the Linux kernels seemed to have relatively recent work / code updates (I think from 2023) not sure if that would be any help because I realize each Sharp Brain model is different. Unfortunately I don’t have the links on hand

Brainux was originally developed for PW-SH1 iirc and ported to other gen3-4 machines, and later, gen 2. So gen 2 support is relatively a recent thing. gen 1 and 5 port is in progress but I don't expect it to be done in short; they are facing huge issues to support them like proprietary hardware in gen 1 and multi-core processor in gen 5.

Sharp sometimes changed the internal hardware while on a single generation (not visible from outside), and it happened more often in earlier generations. Brain Hackers collected bunch of models, disassembled, and categorized them in groups by analyzing the board. When they first looked at PW-A7400, they believed its hardware is the same as PW-A7200 as there were written on the board "PW-A7200 series". But in recent analysis they discovered that it was wrong and PW-A7400 has hardware that is rather middle ground between PW-A7200 and PW-SH1.

They are preparing for official release for this fix: https://github.com/brain-hackers/u-boot-brain/pull/25

The aforementioned experimental patch is a quick patch they developed for PW-A7400 after their recent analysis. I put it here because if the issue is still occurring on PW-A9100, then (I thought) there are (small) possibility that @hassilon 's machine strangely has PW-A7400's hardware inside it. I have never heard of a case about different hardware in a single *model*, but still.

The latest release Brainux 2024-02-04-162841 has just arrived, incorporating various fixes and improvements including the keyboard issue on PW-A7400.
https://github.com/brain-hackers/buildbrain/releases/tag/2024-02-04-162841