[Server-devel] [XSCE] Re: Root fs on XO1

[James Cameron]

On Sat, Aug 10, 2013 at 03:05:18PM -0400, George Hunt wrote:
> Thanks everybody for your responses.
> 
> I learned a lot yesterday by trying things you all
> suggested.  James' idea of using a XO1.5, and
> <devalias. . .,fs-update . . > to populate an SD card was quick, and
> booted on a 1.5.  I tried copying the /boot directory of a XO1 to
> this SD, and it appeared that the signed kernel was recognized,
> loaded, but dracut issued a warning that root argument was empty. 
> 
> So then I read up on dracut. My guess is that the drivers to read
> the SD card were missing from the initramfs.

I don't think that is likely.  The SD card driver is integrated with
the kernel, and is not a module.  (verified on 13.2.0 here).

Rather, I guess that our dracut-modules-olpc package simply hasn't got
scripted support for swinging the kernel over to a root filesystem on
the SD card on XO-1.

http://dev.laptop.org/git/users/dsd/dracut-modules-olpc/

http://dev.laptop.org/git/users/dsd/dracut-modules-olpc/tree/30olpc-boot/olpc-boot-cmdline.sh

The above script is where the decision is made, and XO-1 SD card is
not in the case statement, because we didn't add this support.

So yes, specifying a root filesystem using the command line may be a
workaround.

> Then I started following James' suggestion, looking into
> olpc-os-builder.   There's an sd_image option which can be
> enabled.  I could not determine if enabling that would also enable
> booting from an external USB flash/hard disk, but it seems worth a
> try.

The lack of support in dracut-modules-olpc would still need fixing, in
my opinion.

The sd_image option will make a .zd but XO-1 doesn't have fs-update.

> (I'm still toying with the idea of a WD Passport -- external hard
> disk as the supported option for the XO1 XSCE).

I've avoided that brand because of extra features of the product, in
case they interfere.  Does it work okay?

(Extra features of consumer backup drives _might_ involve changes to
the device in terms of the USB descriptors, such as those required for
a push button to start backup software, or CD-ROM images of the
software, so I've tended to select drives that either don't mention
the software, or are marketed as expansion rather than backup.)

> I'm not yet clear whether it would be any simpler to insist that
> XO1's be unlocked before installing XSCE. It's easy to modify the
> kernel command line via "olpc.fth", (which I verified to be ignored
> on a locked XO) but maybe getting the right drivers in the initramfs
> is the hard part.  I still have lots more to learn.

I really suggest you disable-security.  Unless you have a real or
industrial need for the security system, it will just hurt you over
and over.

-- 
James Cameron
http://quozl.linux.org.au/