rpi kernel

can anyone give me some insight on the differences between

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and the sources on kernel.org ? i.e should the rpi-kernel not be 'mainline' by now, or are there still somemodules etc. that haven't found their way into the kernel tree ? the obvious thing is that there's no bcm2711_defconfig on kernel.org.....

regards -rasp

Reply to
Ralph Spitzner
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I don't know specifically the state of mainline support for the RPi, but in general changes to the Linux kernel are developed out-of-tree, in a separate repo, and then patches are submitted for merging into mainline. That means mainline always lags the development tree. The github.com/raspberrypi/linux tree is the repo where the RPi folks develop their kernel, and any patches may only be submitted to mainline later on. So the RPi tree is likely to be more up to date.

In addition, the RPi tree contains files that probably wouldn't be accepted into mainline, like device tree overlays specific to Pi peripherals.

Theo

Reply to
Theo

Theo wrote on 8/16/21 12:57 AM: [...]

the commits ahead/behind mostly tell different....

that, of course is an argument :-)

-rasp

Reply to
Ralph Spitzner

Unless something has changed recently (I doubt it), the dwc-otg USB driver is specific to the RPi kernel (or at least the RPi version of it, extensively modified from existing sources). It's the default USB driver in RPi OS (for the Pi Zero at least), whereas on distros based on the official Linux kernel the dwc2 driver is used instead (also optionally usable in RPi OS).

The dwc-otg driver has extra performance (uses FIQ interrupts) and functionality (USB On-The-Go) improvements.

Then besides the binary blobs for the GPU, WiFi, and Bluetooth, there are likely other differences, but I haven't gone looking for them specifically.

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Reply to
Computer Nerd Kev

I meant that it's ahead for RPi stuff. It's behind for things which aren't relevant to the Pi. Periodically they will merge or rebase to upstream, perhaps when Linus makes releases. For example there's a rpi-5.14.y branch which is full of Pi related things, and was last synced with upstream Linux 5.14-rc5 on 8 August.

In particular it's notable that the first few commits after 5.14-rc5 are the RPi folks reverting things that don't work for them. So they are basing their tree on mainline but adapting it to their setup. I had to go back through 16 pages of github commits before I found the 8 August merge, so there's a lot of stuff being changed in their tree.

Theo

Reply to
Theo

Computer Nerd Kev wrote on 8/17/21 1:20 AM: [...]

ah, now that sheds some light :-) So there are probably more 'enhancements'/modifications....

thanks -rasp

Reply to
Ralph Spitzner

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