Can I just install Ubuntu onto X20, instead of the official Android ?
If yes, any documentation for me to follow?
Cheers
Pei
I don’t think the state of the art has really moved on much beyond this topic:
The summart is that it is possible with a fair bit of hacking, to install the distro of your choice on the board. However this is only really for developers who want to extend the kernel support: there are no installer to assist with the install and the resulting system will have no display or WiFi.
I’m gonna try and give this a shot today, my x20 is just siting duck, might as well have some hacked stuff run on it…
ayyeee!!!
@danielt your linux brach workied a treat…
root@linaro-alip:~# uname -a
Linux linaro-alip 3.18.22+ #1 SMP PREEMPT Tue Sep 19 12:08:48 IST 2017 aarch64 GNU/Linux
root@linaro-alip:~#
just used the db410c rootfs
now on to mainline (kind off, it’s 4.9-rc1)
Good to hear!
IIRC the mainline-ish kernel didn’t have eMMC enabled… I had it running using a buildroot ramdisk. Again I didn’t have time to try bringing up any extra drivers.
also i was meaning to as there is a kernel cmdline maxcpu=5… whats up with that. Also after boot nproc and proc/cpuinfo only show single core
You mean with the 3.18 vendor kernel? If so, maxcpus=5 prevents the SoC from overheating during early kernel boot, after that there is kernel code to automatically “plug” and “unplug” cores as they are needed. This is a power management technique similar to cpufreq… there is a bit of code what watches the load on the current CPUs (and also the Soc temperature) and adds/removes cores as required. If you run something that consumes cycles you should see new CPUs added in.
For mainline kernel there is (or at least was) very little power management code so maxcpus=5 doesn’t just affect early kernel boot… we are limited to five cpus all the time!
Is this how it’ll work for every big.LITTLE SoC or is it specific to mtk tricluster?
I don’t think mainline kernels do anything like this. In other words its a bit of a hack but AFAIK its quite a common one… not unique to X20.
Wow… any github repo for me to try directly?
Sorry man, me, toooooo lazy…
Did you have it run by LFS?
At least, any BSP file for me to try out?
Cheers
Pei
I landed most of the changes I did in the helio-x20 repo: https://github.com/helio-x20/linux/commits/helio-x20
However its still just raw kernel sources. I used buildroot, loaded via an initramfs, to bootstrap things (I really can’t remember it I used ssh+tar or cdebootstrap-static to populate the rootfs…).
Hi @danielt,
Sorry for the question: does x20 have temperature sensors? And about the max number of cores allowed, its not possible to have all the cores running by your choice?
Thanks.
Yes (its essentially impossible to build a modern phone chip without them). However I’m not sure where the driver code for them is.
I think you can command all the cores to run at once… but the system is likely to preform a thermal emergency reset shortly afterwards unless you have all the CPU frequencies wound down to low levels.
AFAIK the chip wasn’t designed with the intent that all cores run at the same time… they just give more flexibility to hit particular power/performance combinations.
