kernel version

[appleseed]

Kernels never get upgraded by manufacturers.

out of curiosity, couple questions:

1. is this done to segment profit/cost, or a hardware limitation, and;
2. just purely as a thought experiment,
what could you (and others who contribute code) do if Broadcom dropped a modern 2020 kernel out of the blue, that you could not do before ?

I always wondered about that.

 

[heysoundude]

the answer to your first question is YES
as for #2 - have you tried doing what you're suggesting? Give it a go - pull that old 486dx66 out of the cellar or closet and get k5.5+ running on it like on modern infrastructures. (keep a fire extinguisher handy)

 

[RMerlin]

2. just purely as a thought experiment,
what could you (and others who contribute code) do if Broadcom dropped a modern 2020 kernel out of the blue, that you could not do before ?

Nothing worthwhile. And actually, the last time a new kernel was introduced (when HND models were launched on kernel 4.1.27), we lost the iptraffic module which is not compatible with anything newer than early 3.x.

A kernel isn't just a program that you can upgrade. Everything else that ties into it must also be upgraded. Netfilter modules written in the 2.6 eras must be partly rewritten for 3.x. A lot of kernel modules in general must be changed after 2.6.38 when the kernel made changes to locking mechanism. I took like a whole year for Paragon to update the free version of their NTFS driver for it to be compatible with newer kernels following that change.

A kernel is very difficult to upgrade within an existing system. Check your smartphone - same thing. Its kernel doesn't get upgraded between Android releases, only a new device will get a newer kernel. The kernel is tied to the SDK for whatever platform you use. If it's NOT an open platform like x86 is, then the kernel will almost never get upgraded by the SoC/platform manufacturer.

 

[faux123]

As @RMerlin stated, the biggest hurdle is the associated "binary blobs" (closed sourced / proprietary) code that surrounds the particular kernel build. Even if Broadcom decided to drop a Linux 5.8 kernel (the newest) for their current CPUs, the issues will ALWAYS be those proprietary binaries.

I've been hacking Android and kernels for years, the open source side isn't too difficult since we have access to all the code and can read it myself and figure things out, but my challenges have always been how do I hack the kernel without breaking the stuff I don't have access to.

It is a HUGE investment for a manufacturer to tailor a particular kernel to their devices and all the surrounding "binary blobs", kernel is just a small part of their overall investment, for them to "upgrade" their entire libraries to the latest Linux kernel would take months if not years to do with many unknowns (newer code != better) bugs lurking. We are already somewhat lucky that portion of the code is open source and something can be added and enhanced, but we will never have an up-to-date kernel support from the manufacturers.

 

[appleseed]

ok, makes sense. was wondering the same thing about Synology, and I get it now