[syslinux] configuration directive fixes

[Gene Cumm]

On Sat, Oct 16, 2010 at 17:47, Alexey Gladkov <gladkov.alexey at gmail.com> wrote:
> 17.10.2010 00:37, Gene Cumm wrote:
>> I believe it mentions only pointing to a module for a few reasons.
>> For starters, it might look pretty stupid to have a selection in the
>> UI to load itself.
>
> I'm sorry, but this is documentation.
>
>> That said, with menu.c32/vesamenu.c32 you can hide a label from the
>> menu with "MENU HIDE".  At this time, I believe it is implemented
>> exactly like DEFAULT is except it loads immediately rather than being
>> loaded eventually based on TIMEOUT, PROMPT, ONTIMEOUT, user input and
>> possibly other factors.
>
> Yes, UI is implemented like DEFAULT, but I think this is wrong.
> Please, read commit message:
>
> http://git.kernel.org/?p=boot/syslinux/syslinux.git;a=commit;h=e21e66137b454fb3afd50a113de68599dd28de09
>
> Directive 'UI' was created to not abuse directive 'DEFAULT'. But you
> are now proposing to abuse 'UI'.

I don't think I'd consider it abusing UI but perhaps others think
otherwise.  I thought DEFAULT was supposed to be used to indicate a
default end image/kernel/OS to boot while UI was meant to be a program
to start immediately while a user is deciding what to do.  Under that
assumption, I think my suggestion is valid.

It is very possible that I may also have an invalid assumption.

>> If you are using menu.c32/vesamenu.c32 as a UI and want a workaround
>> that does work for now, try one of these:
>
> Why do we need such workarounds, which are not documented?

I just thought try it and it worked.  I wanted to pass along what I
found worked for me thinking you would find such information
beneficial.

>> (side question that probably should be a separate discussion) How do
>> you override a global APPEND for manual command lines or DEFAULT/UI
>> (when DEFAULT/UI does not reference a LABEL)?
>
> I'm not sure if correctly understood the question, but I will answer:)
>
> If you mean the editing options at boottime, then interface module
> (menu/vesamenu) handle this.
>
> If you mean how I change the settings from the section 'LABEL', I
> suggest that second my commit. I added a new directive 'ADDAPPEND',
> which works as in lilo.

Let me restate this as it seems like I might not have been clear.   If
a global APPEND is set in a config, it is always inserted after the
first argument into the command line of a manually entered command
line, a DEFAULT statement or a UI statement (assuming that the DEFAULT
and UI statements are stand-alone statements that do not reference any
LABEL).  With a LABEL, if an APPEND is specified, the global APPEND is
ignored.  If a LABEL APPEND of "APPEND -" is specified, no arguments
are appended.

I think it would be worthwhile to find a way to override this behavior
if desired.

-- 
-Gene