[Arm-dev] Community kernel 4.18.x

[Mark Verlinde]

-----Oorspronkelijk bericht-----
> Afzender:Pablo Sebastián Greco <pablo at fliagreco.com.ar>
> Verstuurd: Woensdag 17 Oktober 2018 18:09
> Aan: Conversations around CentOS on ARM hardware <arm-dev at centos.org>
> Onderwerp: Re: [Arm-dev] Community kernel 4.18.x
> 
> 
> 
> El 17/10/18 a las 11:47, Mark Verlinde escribió:
> > Hi,
> >
> > Kernel 4.18.x brings nice features, CPUFreq for Allwinner H3 SOC's being among them.
> >
> > Therefore I had a go on updating to the community-kernel-latest version 4.18.14-200.el7 which failed;
> > Dracut could not (re)build a intitramfs-4.18.14-.. and (probably because of this) uInitrd-4.18.14-.. was missing to.
> > Unfortunately did not write the exact error message down; next time will do so.
> Does /boot have enough space?, I usually try to have 3 kernels at most.
> I've been using that kernel in 3 different SoCs without problems, 
> including Bananapi M3 (same SoC as the cubieboard5)

I do not doubt it had because it was the second kernel update done (i.e would be the 3rd installed)

However : just successfully installed  with a more conservative approach 4.17.17 > 4.18.9 > 4.18.14
Side note is: this is on a home brew image without RPI bits and peaces, 786MB boot partition with ext4 file-system.
In time I will try again with default Centos-Generic image.

i'm happy now:)
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
ondemand

> >
> > BTW: Update to Kernel 4.17.17-200.el7 was successful on my oragngepi-plus2e
> >
> > In my own interest i'd really want to help to debug this;
> > but to be able to do this i need to understand in more detail how we boot Centos on our u-boot based SBC's.
> > I got the broad picture: u-boot >> extlinux bootloader >> kernel >>
> Correct
> > Getting lost however looking at extlinux/extlinux.conf , grub/grub.conf and not knowing the content of boot.scr
> You can ignore grub.conf and boot.scr, extlinux.conf is all you need

Sorry to persist, I'd really like to understand in more detail;
Questions circling in my head (among others)  are:
Why do we have a uInitrd _and_ initramfs ?
Why do we have a uimage _and_ vmlinux ?
Why does my odroid HC1 boot with a Fedora image but not with Centos (kernel 4.14.71 nor 4.17.17)? (despite specific USB3 patches are backported to 4.14)

> >
> > Can somebody enlighten me on this, or show me some further reading.
> >
> > (I did search fedora's arm documentation without getting smarter..)
> >
> > Actually in response to "Cubieboard5 performance"
> > (https://lists.centos.org/pipermail/arm-dev/2018-October/003515.html)
> >
> >
> > _______________________________________________
> > Arm-dev mailing list
> > Arm-dev at centos.org
> > https://lists.centos.org/mailman/listinfo/arm-dev
> >
> _______________________________________________
> Arm-dev mailing list
> Arm-dev at centos.org
> https://lists.centos.org/mailman/listinfo/arm-dev
>