Mainline linux kernel

[Bob Ham]

For info on Debian 9 for Gemini

For kernel compilation

Hi Mark,

This thread is about mainling support for the Gemini.  That means sending patches upstream to the Linux developers so that Linus' releases contain support for the Gemini.  This can be a very involved and technical process and can take a long time.

Instructions on how to install Debian or compile the kernel aren't much help but thank you :-)

Cheers,

Bob

[ArchiMark]

For info on Debian 9 for Gemini

For kernel compilation

Hi Mark,

This thread is about mainling support for the Gemini.  That means sending patches upstream to the Linux developers so that Linus' releases contain support for the Gemini.  This can be a very involved and technical process and can take a long time.

Instructions on how to install Debian or compile the kernel aren't much help but thank you :-)

Cheers,

Bob

Got it, Bob!

Thanks,

Mark

[Bob Ham]

I had a look at whether any of the patches here

https://github.com/freedomtan/patches-mainl...ard/tree/master

had been accepted in the kernel and indeed it looks like mainline now supports the X20 development board:

https://git.kernel.org/pub/scm/linux/kernel...ep&q=mt6797
https://git.kernel.org/pub/scm/linux/kernel.../mt6797-evb.dts

The X20 is MT6797, the X25 is MT6797T and the X27 is MT6797X.

So the bulk of the basic work is done.  According to wikichip.org, the X27 is "identical" to the X20.  I'm curious as to just how "identical" and whether a kernel built for the X20 will run on an X27.

The board name is apparently "aeon6797_6m_n", according to the Lineage kernel config.  The .dts file for the 3.18 Android kernel is here:

https://github.com/gemian/gemini-linux-kern...on6797_6m_n.dts

Unfortunately, nearly all of the entries are 'compatible = "mediatek,...";' meaning it's probably all mediatek hacks as drivers.

[mifritscher]

TheKit managed to boot a mainline X20 kernel at the gemini - almost, stuck at switching to user mode (or initrd)

I collected some informations at https://github.com/gemian/gemini-keyboard-a...LinuxMainlining . Here is also a boot log.

[speculatrix]

I'm hopeful we will see kernel 4.something for the Gemini, maybe along with a release of Android O or P, but I don't think it will be any time soon. Long term, we'll be reliant on third parties getting newer kernels to run on the Mediatek SoC, because Mediatek will have moved on.

[mifritscher]

I think that it is indeed possible to get all needed bits mainlined. Most, if not all components in kernel are OS, they need "only" to be fit to get into mainline kernel (and if only into staging as a first step) And for mali - the friends at panfrost are very active.

Overall I think we are at a position where the linux-sunxi.org people were a few years ago. And nowadays, almost all things are running with a mainline kernel.

[Adam Boardman]

This is a page that contains the state of the mainlining project (edit: didn't read the last page of comments it seems, mifritscher already mentioned this):
https://github.com/gemian/gemini-keyboard-a...LinuxMainlining

Also to point out that Omegamoon on irc managed to get UART console out of the kernel via a USB cable using a modified version of these instructions (using an FTDI): http://www.stevenhoneyman.co.uk/2014/11/mt...ebug-cable.html

It also sounds like just getting a pound shop USB C charge+data cable and cutting it open and wiring to the serial port on a Raspberry Pi could also work for those without an FTDI but a RPi.

[Murple2]

TheKit managed to boot a mainline X20 kernel at the gemini - almost, stuck at switching to user mode (or initrd)

I collected some informations at https://github.com/gemian/gemini-keyboard-a...LinuxMainlining . Here is also a boot log.

The bootlog is 404, does anyone have another link to it?

I have been trying to boot mainline now I have a UART cable but I keep getting device tree not found error. I was creating boot images with mkbootimg and using the --dt option to specify the dtb, but i've also tried appending the dtb to the kernel image. Both methods give me the same error. IMO appending the dtb to the kernel is hacky and very un-futureproof, does anyone know why we are doing this? Is it a limitation of our version of lk? I know old arm boards did this as a workaround for nonexistant or  buggy device tree support in their bootloaders, but this is going back years. It shouldnt be required in the world of arm8 and mature multiplatform support in the kernel

[TheKit]

I have been trying to boot mainline now I have a UART cable but I keep getting device tree not found error. I was creating boot images with mkbootimg and using the --dt option to specify the dtb, but i've also tried appending the dtb to the kernel image. Both methods give me the same error. IMO appending the dtb to the kernel is hacky and very un-futureproof, does anyone know why we are doing this? Is it a limitation of our version of lk? I know old arm boards did this as a workaround for nonexistant or  buggy device tree support in their bootloaders, but this is going back years. It shouldnt be required in the world of arm8 and mature multiplatform support in the kernel

You need to append dtb to Image.gz. MediaTek's lk bootloader actually handles device tree (there is no appended dtb support for aarch64 in kernel), but in current implementation bootloader searches for appended device tree. The reason is that --dt option isn't/wasn't standard for abootimg format, it's generally used only by Qualcomm devices.

[Murple2]

You need to append dtb to Image.gz. MediaTek's lk bootloader actually handles device tree (there is no appended dtb support for aarch64 in kernel), but in current implementation bootloader searches for appended device tree. The reason is that --dt option isn't/wasn't standard for abootimg format, it's generally used only by Qualcomm devices.

Thanks, I will give this another try. I was doing this:

Code: [Select]

cat Image.gz dtb_file > Image-dtb >
Is this correct? I also tried gunzipping the Image, appending and the gzipping it back up. But I dont think thats right..?

[TheKit]

Thanks, I will give this another try. I was doing this:

Code: [Select]

cat Image.gz dtb_file > Image-dtb >
Is this correct? I also tried gunzipping the Image, appending and the gzipping it back up. But I dont think thats right..?

Code: [Select]

cat Image.gz dtb_file > Image.gz-dtb is the correct way, yes, this worked for me.

[Kero]

When I tried

Code: [Select]

make Image.gz-dtbit just worked

[Murple2]

When I tried

Code: [Select]

make Image.gz-dtbit just worked

Is that with the mainline kernel source?

[Kero]

Hm, no.

[mifritscher]

hmm, 4.19 seems to have a lot of cool stuff for x20 /mt 6797  https://www.phoronix.com/scan.php?page=news...-4.19-ARM-Early