Re: booting the samsung chromeboot xe303c12 with the debian armmp kernel

[Ian Campbell <ijc@hellion.org.uk>]

On Mon, 2014-11-17 at 19:13 +0000, David Edmondson wrote:
> On Mon, Nov 17 2014, Pedro Bulach wrote:
> > I am stuck at a similar situation, where the kernel is loaded but
> > fails to boot the box. A screenshot is attached. I have built upstream
> > kernels 3.17.2 and 3.18-rc4 over the weekend, both with the same
> > results.
> 
> I built a kernel according to the instructions on the linux-exynos
> wiki[1]. When I 'bootm ...' (no initrd), the boot loader outputs a bunch
> of text, much as your screenshot. A few minutes later (I didn't time it,
> but much longer than you would normally expect to wait), the screen
> cleared, two penguins are shown and some kernel messages scroll
> past. The screen clears again, and I'm left with it blank.
> 
> So, _something_ works better with the kernel from the linux-exynos
> github repository, even if it doesn't get all of the way (but it may be
> that I messed up my incantations in uboot).

I suppose the linux-exynos kernel+config is an Exynos only config,
whereas the Debian kernel is a multiplatform kernel. It's only recently
(v3.15/16? not sure) become possible to include exynos in a
multiplatform kernel config, prior to then it didn't play nice with
other platforms.

So I wouldn't be completely shocked if there were still more things
which need working on in that context upstream, like fb support.

I'd also not be all that shocked if there were simply a few more options
which we need to enable in our existing kernel though.

> > I am using nv-uboot-simplefb, which I believe is simplefb-enabled.
> >
> > My current plan is to build the cros kernel and install it as a uImage
> > on the boot partition to validate the setup. Once it works, I will go
> > back to the upstream kernel, and then to debian's kernel.

This strikes me as a good plan of attack, although I'd be inclined to
insert "upstream v3.16.x kernel" between (latest) "upstream kernel" and
"Debian's kernel", since in view of the newness of Exynos multiplatform
support it's not impossible that v3.17,18,etc might improve things. If
that turns out to be the case we can look into backports etc.

Ian.