Re: [RFC] flash-kernel hook to prepend to boot script

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

On Thu, 2014-06-05 at 15:13 -0600, dann frazier wrote:
> > Bootloader-Sets-Incorrect-Root is marked "required" in the README but is
> > omitted from X-gene. I think since 850c8fc3 the behaviour when missing
> > is now to treat it as "no" which is the sane default, so perhaps the fix
> > is to make the README reflect that rather than fiddle with the Xgene db
> > entry.
> 
> Either works for me.

Lets update the README then, this setting is supposed to be used for
exceptional cases anyhow. If you feel like nuking all the existing :yes
entries that would be great too.

> > flash-kernel upgrade rather than on install via di is a worry. Bootargs
> > gets overridden to the default from /etc/default/flash-kernel which will
> > be missing root= etc. On my cubietruck after dpkg -i of 3.20 I 've ended
> > up with:
> >         setenv bootargs 'quiet'
> > in my boot.scr, which isn't going to boot I think. (actually, I as
> > discovered below it probably would, although missing console= is a
> > concern...)
> >
> > This could just mean that we need to be a bit careful when adding
> > @@LINUX_KERNEL_CMDLINE@@ to existing bootscripts, since we've not
> > released with CT support I think it would be safe to do in that case.
> > Other than that I'm at a loss what to suggest, perhaps something probed
> > from /proc/cmdline when first installing a version >= 3.20?
> 
> That sounds reasonable/correct to me - I don't want to make anyone
> unbootable, even in sid->sid upgrades. But my debconf foo is weak, so
> I'm not sure what the best way to do this is.

Me neither.

>  Maybe we could add a
> mapping of model strings and the corresponding f-k version at which
> each model started including L_K_C support to the postinst. When
> crossing that boundary (version test), we could preload any
> non-duplicate /proc/cmdline options to flash-kernel/linux_cmdline.
> 
> Here's an untested patch to explain using code:

I think you can put the transition version into the DB eg.
Bootscript-Bootargs-From: 3.20

> 		"Cubietech Cubietruck")
> +			transver=1.20 ;;

ITYM 3.20?

Another approach would be to add the marker to all of the scripts and
just do it unconditionally for installs of 3.20 onwards and require all
new scripts to use it in the future. I appreciate why you might not want
to risk changing some of the existing ones though.

Another possible alternative would be to check for the presence of magic
string in the specified boot.scr.

Ian;