Re: booting the samsung chromeboot xe303c12 with the debian armmp kernel
On Mon, 2014-11-17 at 08:13 +0000, David Edmondson wrote:
> On Thu, Nov 13 2014, Pedro Bulach wrote:
> >>> Looking at the Debian kernel configuration, it appears that
> >>> CONFIG_FB_SIMPLE is not enabled in the armmp kernel. This would appear
> >>> to be a requirement for the simplefb variant of u-boot (can anyone
> >>> confirm?).
> >>
> >> I think we could pretty safely enable that, although I'd be much happier
> >> if someone could try it first. I don't think I have any relevant h/w in
> >> the right places.
> >
> > Good catch! I will try to rebuild the kernel over the weekend enabling
> > the simplefb and test again, and report back.
>
> Having built a kernel[1] with CONFIG_FB_SIMPLE and adding the
> flash-kernel support, I can properly generate the kernel, initrd and dtb
> images, but the result still doesn't usefully boot.
>
> When I run 'bootm ...' there is some text printed by the loader (much as
> before CONFIG_FB_SIMPLE), and then the screen clears to blank.
I don't know a whole lot about this fb simple stuff, but doesn't it
require the bootloader to pass in some DT nodes telling it where it
ended up putting things? Does the u-boot you have do that? The protocol
was only recently agreed (although there was some sort of precursor in
the field).
Sorry to be so fluffy, I only have the vaguest notion of how any of this
stuff fits together...
> I recall
> from a previous attempt at this some months ago that it can take a while
> for the kernel to use the framebuffer, but after 10 minutes nothing has
> changed. The access light on the USB stick (which has nv-uboot, /boot
> and /) has not lit.
>
> The screen clearing to blank is new - that didn't happen with the
> previous kernel - so I'm trying to presume that it's a good sign ;-)
;-)
> Footnotes:
> [1] Which took many hours on a Banana Pi...
I bet it did!
FWIW I often build on x86 with the aarch64-linux-gnu-gcc cross compiler
from Linaro in my $PATH and
dpkg-buildpackage -aarmhf -<other usual options>
IIRC I had to add a symlink because Linaro's compiler includes more/less
elements of the version number compared to what the kernel build system
expects (i.e. ...-gcc-4.8 vs ...-gcc-4.8.3 etc, I don't recall which way
round it was though...)
Ian.
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