Linux on CX II CAS Status

→ **MyCalcs** profile · by **technogeek48** » 16 Apr 2021, 05:22

I have attempted to boot kernel and initrd from https://tiplanet.org/nspire_linux_builds/ using the CX device tree.

It does seem to be "kindof" working but the LCD content is garbled (see my post on GitHub : https://github.com/tangrs/nspire-linux- ... /issues/14)

I am wondering if we have the information for the LCD controller like for the CX II at https://hackspire.org/index.php?title=M ... controller

As far as I can tell, the LCD is PL111 which has not changed since CX1.

I am wondering what is the status of Linux on CXII(CAS) and what else is needed for support ?

My calculator programs · by **Adriweb** » 16 Apr 2021, 08:18

It's working just fine with patches

They are being upstreamed by Vogtinator, so I believe you can find them on the mailing list.

→ **MyCalcs** profile · by **technogeek48** » 16 Apr 2021, 15:26

I have searched the mail archive and didn't find anything recent, but I will keep an eye on it.

Also wondering if there is any hardware difference between CX2 and CX2CAS ?

→ **MyCalcs** profile · by **Lionel Debroux** » 16 Apr 2021, 15:41

There are many differences between the CX I and CX II, but not between the CX I non-CAS and CX I CAS, and not the CX II non-CAS and the CX II CAS, AFAIK.

→ **MyCalcs** profile · by **Vogtinator** » 17 Apr 2021, 11:13

You can try with kernel and device tree from https://github.com/Vogtinator/linux, cxII-clean branch. Most USB fixes and the keypad IRQ fix landed upstream already, I didn't get around to submit the rest yet.

The commits relevant for the LCD are "drm/panel-simple: Add TI-Nspire CX II panel" and the device tree which makes use of the new panel type.

→ **MyCalcs** profile · by **technogeek48** » 17 Apr 2021, 16:50

Oh nice! I didn't think to look at the branches on your fork.

I have compiled it a couple times now with .config from https://github.com/Vogtinator/nspire-li ... ree.config and various cross compilers. I'm also using the new nspire-cx2.dts . However it just hangs on the linuxloader2 screen with some display corruption appearing after a while. This is actually the same behavior as the mainline kernel I compiled yesterday.

Which compiler are you using and is there any different config options needed ?

→ **MyCalcs** profile · by **Vogtinator** » 17 Apr 2021, 17:01

Indeed, that config won't work. I put the config I'm using into a cxII branch: https://github.com/Vogtinator/nspire-li ... ean.config

→ **MyCalcs** profile · by **technogeek48** » 17 Apr 2021, 17:29

Nice, that config boots! However, LCD is rotated and corrupted. I can also confirm that the keypad is working. I'm going to try to get a newer busybox next.
(screenshot : https://drive.google.com/file/d/1zHzOWE ... sp=sharing)
(edit: USB seems to work too)
(edit2: can successfully ping calculator over usb gadget cdc-eem)

→ **MyCalcs** profile · by **technogeek48** » 17 Apr 2021, 21:16

Update: I compiled a small busybox userspace with buildroot and dropbear sshd, the system seems to be working fine except for LCD.

There is some drm related error in dmesg : https://gist.github.com/mj-sakellaropou ... 66c4d4f675

I have also noticed SPI address from hackspire wiki does not match device tree, although changing it does nothing.

→ **MyCalcs** profile · by **Vogtinator** » 18 Apr 2021, 11:43

technogeek48 wrote:Update: I compiled a small busybox userspace with buildroot and dropbear sshd, the system seems to be working fine except for LCD.

There is some drm related error in dmesg : https://gist.github.com/mj-sakellaropou ... 66c4d4f675

I have also noticed SPI address from hackspire wiki does not match device tree, although changing it does nothing.

My suspicion is that you're using a prebuilt linuxloader2 which still triggers LCD compatibility mode. That isn't reset when linux boots and causes a conflict. It should work after rebuilding it with a recent version of the SDK.

I pushed a clean rebuild of the latest git version to https://tiplanet.org/nspire-linux-builds/.