Linux kernel 6.1 or 6.6 for OpenWrt 24.x release?

[Hauke Mehrtens]

On 2/3/24 15:31, Paul D wrote:
> On 2024-02-03 13:06, Hauke Mehrtens wrote:
>> Hi,
>>
>> I track the status of the Linux kernel 6.1 migration in this github 
>> issue: https://github.com/openwrt/openwrt/issues/14546
>>
>> There are still many targets on kernel 5.15 without testing support 
>> for kernel 6.1 in OpenWrt master. I assume that we need at least 4 
>> months to get everything to 6.1 and more or less stable. Kernel 6.1 
>> support is also missing for some important targets like lantiq, 
>> realtek and ramips.
>>
>>
>> Which kernel should we use for the next major OpenWrt release?
>> We have two options and I would like to get some feedback on these:
>>
>> 1. Do the OpenWrt 24.X release with kernel 6.1. Branch off when all or 
>> most of the targets are on kernel 6.1 by default.
>> 2. Do the OpenWrt 24.X release with kernel 6.6. Branch off when all or 
>> most of the targets are on kernel 6.6 by default. Do not do any stable 
>> OpenWrt release which supports kernel 6.1.
>>
>> Doing a OpenWrt release with multiple kernels cases too much 
>> maintenance effort from my point of view based on previews experience.
>>
>>
>> I think with kernel 6.1 we can branch off at around May 2024. With 
>> kernel 6.6 we could probably branch off around September 2024. The 
>> final release will be out about 2 to 4 months later.
> 
> Do a release using 6.6 - although from past experience this means no 
> OpenWrt 24.
> 
> 6.6 likely means carrying fewer patches also.
> 
> Does this give rise to the potential that some older devices get dropped?

Linux kernel 6.6 will probably be 5% to 10% bigger than Linux kernel 6.1 
as I have seen it between other LTS kernel versions.

Maintenance of kernel 6.6 will be easier because we have to carry less 
patches and we will be closer to upstream.

I expect that using kernel 6.6 will push out the next release by about 4 
months. I expect that the first target with kernel 6.6 testing support 
will be in master in less than 1 month after we decide to use kernel 6.6 
for the next release.

Hauke