Kernel downgrade through apt and Mainline Kernels

[Euler]

Hello everyone!

I'm using rk322x TV box for video decoding through mpp. Mpp requires a system with 6.1 or earlier kernel. When I try to compile Ubuntu 22.04 from this repository https://github.com/armbian/build, the selection for kernel are "current" or "edge". I selected "current", and later I found its kernel is 6.12.21. I have tried to use armbian-config to downgrade the kernel, but the earliest selection is 6.6. Then I tried to downgrade the kernel through apt, but there were no 6.1 edition. Thus, I decided to change the kernel through "Mainline Kernels" and install the 6.1.132 kernel. After the installation finished, I rebooted my system and found that the kernel was still 6.12.21, I have no idea what to do next, so I am here asking for help.

Apologize for my poor English, and greatly thanks for your help.

[Igor]

Mainline kernels or kernels from Ubuntu / Debian won't work on most of those devices. For several reasons. And if they will work by some luck, they will have less functions enabled / operational. Probably here you are looking for a vendor provided kernel 6.1.y, which we provide for some flagship devices. You can try to install "vendor" kernel from repository (with matched dtb), but you need help from higher power or some work, where you will most likely need to do it alone - our team is not touching this hw with this kernel and we don't have resources to deal with this, to get it working. It requires time nobody have - you need to find people that share this wish / problem and try to do something. And this is where this forum might help. 

& moving to TV boxes.
 

7 hours ago, Euler said:

video decoding through mpp. Mpp requires a system with 6.1 or earlier kernel.

This part I don't know.

[Euler]

Thanks for your explanation!

According to your reply, I have two question:

1. Where is the repository?

13 hours ago, Igor said:

You can try to install "vendor" kernel from repository (with matched dtb)

You note that I can install "vendor" kernel from repository, but actually I have no idea where the repository is. Since Ubuntu/Debian have a archive website for downloading all previous kernel, library and software, I think there must be a website that saves all kernel for download. However, I can only find recent mirrors from https://stpete-mirror.armbian.com/archive/.

2. Does this mean I have to compile the kernel from the vendor's official repository?

I have found the kernel repository provided from Rockchip: https://github.com/rockchip-linux/kernel/tree/develop-6.1. Should I download the source code and compile it?

About mpp:

13 hours ago, Igor said:

21 hours ago, Euler said:

video decoding through mpp. Mpp requires a system with 6.1 or earlier kernel.

This part I don't know.

MPP stands for "Media Process Platform," which Rockchip specifically designed to drive the internal video encoder and decoder of the chip. It can be used to accelerate the speed of video encoding or decoding. Here is the link to the repository: https://github.com/rockchip-linux/mpp.

Looking forward to your reply!

[Werner]

vendor is just a name for one of our three main branches besides current and edge.

The vendor name refers to the fact that this kernel is built from rockchip sdk sources (which is Linux 6.1.y but HEAVILY modified) with a bunch of our own patches on top.

Though this branch is mainly for rk35xx devices. No idea how much work for rk32xx or rk33xx devices was made there.

[Igor]

2 hours ago, Euler said:

I have two question:

 

First you need read FAQ as you might be missing some important facts https://forum.armbian.com/forum/189-faq/

 

2 hours ago, Euler said:

Where is the repository?

 

https://apt.armbian.com (APT packages)

 

2 hours ago, Euler said:

I have found the kernel repository provided from Rockchip: https://github.com/rockchip-linux/kernel/tree/develop-6.1. Should I download the source code and compile it?

 

In reality you need TV box vendor adjusted kernel source. Which is impossible to find as its often not even released. You need to find (extract from official FW) hardware settings ("device tree") for your model or not everything will work. Nobody can help you from developers perspective. You can only hack this on your own or with help of other end users. (Armbian) developers are mainly avoiding this endless pile of junk hardware. 

 

Absolutely no warranty that any of this will work, just chances of success are > 0% (your initial approach).