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Is mainline kernel perfectly good for Raspberry Pi 3 B+?

Posted: Sun Mar 24, 2019 9:17 am
by crocket
Do I still need to use https://github.com/raspberrypi/linux?

Re: Is mainline kernel perfectly good for Raspberry Pi 3 B+?

Posted: Sun Mar 24, 2019 9:46 am
by B.Goode
In what way is the kernel shipped by default with the Raspberry Pi Foundation recommended and supported Raspbian Operating System, available for download and installation from https://www.raspberrypi.org/downloads/raspbian/, not suitable for your needs?

Re: Is mainline kernel perfectly good for Raspberry Pi 3 B+?

Posted: Sun Mar 24, 2019 10:04 am
by epoch1970
Look at the commit history, then decide for yourself.

Re: Is mainline kernel perfectly good for Raspberry Pi 3 B+?

Posted: Sun Mar 24, 2019 12:56 pm
by crocket
I think it is not good for the downstream raspberrypi kernel to differ from mainline kernel in the long run.
If mainline kernel supports raspberry pi perfectly, I would use it instead. Although I track the status of upstreaming with https://github.com/raspberrypi/linux/wiki.atom, I wanted to know whether other rapsberry pi users knew better.

By the way, I successfully compiled raspberrypi kernel, installed kernel modules, compiled ZFS, and installed gentoo linux on ZFS root on raspberry pi.
The whole process took two days. I was surprised that it wasn't very difficult to bootstrap gentoo linux on raspberry pi with ZFS root because I never used an ARM single board computer before. Although I had many doubts before I actually used it, I like it now. Soldering quality is excellent unlike cheap chinese knock-off products. It is a state-of-the-art product although it can still improve a lot in the future.

Raspberry Pi developers paid attention to details that a gentoo user like me appreciates.

Re: Is mainline kernel perfectly good for Raspberry Pi 3 B+?

Posted: Sun Mar 24, 2019 1:42 pm
by mahjongg
Perhaps next time you could word your question a bit less confusing, it was flagged for being too obscure, and potentially read as if there was something wrong with the current kernel. :) .

Re: Is mainline kernel perfectly good for Raspberry Pi 3 B+?

Posted: Sun Mar 24, 2019 1:55 pm
by crocket
mahjongg wrote:
Sun Mar 24, 2019 1:42 pm
Perhaps next time you could word your question a bit less confusing, it was flagged for being too obscure, and potentially read as if there was something wrong with the current kernel. :) .
One personal development tip that I know is to ignore negative criticisms and accept feedbacks.

Re: Is mainline kernel perfectly good for Raspberry Pi 3 B+?

Posted: Sun Mar 24, 2019 3:55 pm
by jamesh
crocket wrote:
Sun Mar 24, 2019 1:55 pm
mahjongg wrote:
Sun Mar 24, 2019 1:42 pm
Perhaps next time you could word your question a bit less confusing, it was flagged for being too obscure, and potentially read as if there was something wrong with the current kernel. :) .
One personal development tip that I know is to ignore negative criticisms and accept feedbacks.
Another tip is to Google before posting.

But since you have asked rather than Googled,

When it originally launched, the Pi kernel was fairly custom. Lots of bits of HW in there that were not supported by mainstream. Over time, as the Pi has become more popular, more and more of the Raspberry Pi specifics have been brought up to kernel coding standard, and accepted in to the mainline tree . Not only that, but some of the mainline drivers used in the Pi kernel have been bug fixed by Raspberry Pi engineers and changes accepted upstream. There are some areas of code that can never be accected upstream due to their nature, but these are not essential to boot the Pi, just for some of the HW features that people may want to use.

There is an ongoing effort to upstream as much as possible by Pi enginers and third parties, because it reduces the maintenance burden.

So, to answer you orininal question, mainline wil work, but has missing features. I suggest using Raspbian, it's our development distro so is ahead of mainline, its bug fixed, and it supports all the features of the Pi (apart from 64bit).

Re: Is mainline kernel perfectly good for Raspberry Pi 3 B+?

Posted: Fri Mar 29, 2019 5:23 pm
by swahren
crocket wrote:
Sun Mar 24, 2019 9:17 am
Do I still need to use https://github.com/raspberrypi/linux?
No, you don't have to, but it isn't perfectly good. At the end this comes to a more philosophical question, what is perfect.
The advantage of a vendor tree is to hack a lot of optimizations for your target device, which will never acceptable for the upstream kernel.

Anyway in Upstream Linux 5.0 there are some missing features (planned):
CPU frequency driver
DT Overlay support

Also there are some differences in usage (e.g. GPIO handling, DTB for every board).

In case you are interested there are distribution, which are using mainline kernel and there is a mailing list dedicated for Raspberry Pi mainline.

Re: Is mainline kernel perfectly good for Raspberry Pi 3 B+?

Posted: Fri Mar 29, 2019 5:48 pm
by PhilE
Anyway in Upstream Linux 5.0 there are some missing features (planned):
...
DT Overlay support
This is the runtime dtoverlay support - the firmware can still apply overlays.