Bug#393079: update-grub: savedefault can cause problems

[Peter Cordes]

On Sun, Oct 15, 2006 at 12:02:14PM +0200, Robert Millan wrote:
> 
> Btw, your Mail-followup-to header screwed my reply.  Please don't use that
> header when submitting bugs to BTS.

 Sorry;  I used Ubuntu's reportbug and then changed some headers without
realizing all the headers it sets.  Hopefully I'm not causing more problems
by CC'ing Ubuntu's BTS on this. :>

 Also sorry for the delay;  enough computer problems at work that I didn't
want to look at this one again :(

> On Sun, Oct 15, 2006 at 12:00:39PM +0200, Robert Millan wrote:
> > On Sat, Oct 14, 2006 at 06:08:03PM -0300, Peter Cordes wrote:
> > > 
> > >  So I don't know where grub could save defaults to, and I'm not shocked that
> > > savedefault doesn't work.  I've always been suspicious about by default
> > > writing to the hard drive while booting, but this is the first time
> > > savedefault has ever actually caused a problem.  My opinion is that it's not
> > > such a great default.  The standard grub menu.lst doesn't use the saved
> > > default anyway.  I would suggest making savedefault another
> > > automagic-comment configurable item, defaulting to off.
> > 
> > Yes indeed, savedefault is implemented by writing into MBR.  Unfortunately, we
> > had to diverge from upstream on this, and it resulted into a handful of problems
> > I'd rather not get into.  Given that it's not enabled by default, though, I
> > think it's safe to do another release with it.

 It actually is enabled by default.  It's the savedefault in every entry
that's the problem, not when reading it by specifying "default saved".
update-grub always writes savedefault in every entry (except the "alternate"
ones), right?

 Maybe update-grub could have an option for including savedefault or not, or
it could include it only if it sees a "default saved" or "fallback saved"?
That sounds likely to confuse anyone who actually wanted to figure out what
was going on, but might "just work" for more people.

 The error message I included was for Ubuntu's default boot menu, which has
no noticeable difference from Debian's.  (no surprise there...)

> > For etch+1 this will all be taken over by GRUB 2.

 Happy hacking :)

-- 
#define X(x,y) x##y
Peter Cordes ;  e-mail: X(peter at cor , des.ca)

"The gods confound the man who first found out how to distinguish the hours!
 Confound him, too, who in this place set up a sundial, to cut and hack
 my day so wretchedly into small pieces!" -- Plautus, 200 BC