Kernel upgrade for Xperia X (and other phones?)

Well, having fully functioning community build and even a working patch for the paid Sailfish X didn't exactly help with the X Compact version. Though at one point it was asked for almost as enthusiastically as the kernel update is now.

I'll try to look into it, but this is my daily driver so it'll depend on how severe I may knock myself out.

@Keeper-of-the-Keys it usually involves a lot of reflashing your device, so if its your every day device then that could get annoying

@r0kk3rz Is there any online documentation on the process? It's not possible to just build a new kernel rpm or even build a new kernel and copy it to the right path?

https://sailfishos.org/wiki/Sailfish_X_Xperia_Android_9_Build_and_Flash

No, you can't just build a new kernel and flash it and expect it to actually work, and the reasons for this are somewhat complicated. This is certainly not like updating the kernel in your linux pc!

I asked that question and that is about the Android support side of things, regardless of Android support kernel 4.14 is very much preferable over a kernel that no longer gets driver fixes or security patches.

4.4, 4.9 and 4.14 are all long term support kernels meaning each has a 5 year support cycle, the cycle for 4.4 will end beginning 2021, 4.9 end 2021 and 4.14 end of 2022 so since driver support is apparently excellent for 4.14 it would be ideal to switch to that kernel and not a version that is already more then halfway through its' lifecycle.

If the kernel update also enables a serious Android support update that is a huge bonus but that is not the goal, the goal is to have a secure and maintained OS stack on SFOS defintely considering the fact that we can't trust that Jolla has enough manpower to backport security patches to the kernel (and it's a huge waste of manpower when you can "just get it" upstream).

@Keeper-of-the-Keys i thought, the Android upgrade would be dependent on the Kernel upgrade, this was the reason why i posted your statement. So it would be a win win situation, a newer Kernel would fix a lot of security issues, and if the Alien Dalvik would be that adapted that it could be ported from one Sailfish phone to another with a minimal changes, then we would finally see, the long awaited Android Update for the Sailfish OS pioneers, and the probably largest device user base. So it would just be logical to go that step, no matter how much time or manpower it would cost.

Also considering Jolla profiles itself as the privacy/security conscious OS it is really very strange that we are stuck on a by definition hard to keep secure kernel for no good reason. (On the Jolla 1 it is kind of understandable since I can't find any source to indicate that its' SoC is properly supported on newer stuff but for the Xperia X Sony says it is supported on kernel 4.14)

Well, lack of resource would be a reason. Each new kernel version from Sony, means a new firmware package (with blob drivers for everything) and basically means a whole new Baseport layer. (with probably a few "hardware (bluetooth/GPS/FM/whatever) not working" popping upon each new Baseport introduction). And given they limited resoure they have to prioritize one single platform, usually the latest for which there are still phone sold on the market. That's also why, as r0kk3rz mentions, having a working proof of concept helps: it's get half the way to a workable upgrade.

But I agree that it would be wonderful if they managed to streamline the process, to the point where not to long after the start a new Baseport (say 9 or 10 , for the upcoming Xperia 10 running respectively 9 Pie or 10 Q), they could backport and merge effort with older deivces (bringing said Baseport 9 to Xperia XA2 and Xperia X).

That would require a bit more work (and again dev time is something they seem to have in short supply), but would definitely help raise the long term confidence in the platform, and also security (thanks to patches in more recent kernel) and probably even feature (some problems of older kernel are actually fixed in newer: the uSD cards problem on Xperia X seems to be dependent on kernel version, some newer version of the camera firmware are better, etc.)

@DrYak It could be that libhybris makes things harder but in general Linus Torvalds is very close to 100% intolerant of any change to the kernel that affects user interfaces - internal kernel interfaces (ABIs) can change constantly but APIs have to remain stable no matter what (there are lots of examples on the kernel mailing lists of this, if you do want to break/change APIs you had better have a very very very good reason before trying) so strictly speaking all hardware drivers that are in the kernel should be OK since at least according to Sony's evidence the latest kernel supports this SoC and all related hardware in its' entirety. Thus kernel upgrades should be almost drop-in changes.

I do realize however that on SFOS there may be things that are crossing the kernel-userland boundries that make this harder, I'm guessing people like @r0kk3rz know way more about this.