Re: flash-kernel and dtb

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

On Sat, 2014-06-14 at 15:37 -0700, Vagrant Cascadian wrote:
> On Sat, Jun 14, 2014 at 11:56:01PM +0200, Karsten Merker wrote:
> > On Sat, Jun 14, 2014 at 10:36:43PM +0200, Rainer Dorsch wrote:
> > It looks like you might not have set a console device, so
> > possibly the kernel boots, but you do not see any output.  Try
> > setting the console device on the kernel commandline with a
> > command like:
> > 
> >   setenv bootargs 'console=ttyS0,115200 rootwait panic=10'
> >
> > (The example assumes that the serial port on the i.MX6 is ttyS0 and 
> > not something else such as ttyAMA0.)
> 
> The cubox-i uses ttymxc0.
> 
> 
> As I've been writing up a few bootscripts for flash-kernel lately, I've been
> wondering about what makes sense for bootargs...
> 
> With flash-kernel 3.20+, bootargs from the u-boot env are silently ignored
> when using bootscripts that set bootargs... the default bootargs is "quiet".
> 
> Should the bootscript only set bootargs if not already set by u-boot?

I'm not sure, but I agree that it is something which needs thinking
about.

dannf was looking into preserving /proc/cmdline
into /etc/flash-kernel/default when upgrading to a new flash-kernel with
this new behaviour, which would be a good start, I think.

The right answer might be platform specific, since it depends somewhat
on the ability of the user to play with the u-boot env (i.e. on the
presence of a serial console etc).

There's also the question of to what extent we expect people to have to
modify their u-boot env after installing Debian. Ideally no mods would
be needed, but sometimes the defaults are just useless so personally I
don't have a problem with documenting changes for platforms where the
user has console access.

Ian.

> Then dpkg-reconfigure flash-kernel, or editing /etc/default/flash-kernel,
> will be silently ignored if it's set in the u-boot env.
> 
> Neither way seems optimal. I guess setting \$\{bootargs\} in
> /etc/default/flash-kernel might work to inherrit the u-boot env value... but
> that's a bit non-obvious.
> 
> 
> live well,
>   vagrant