Bug#423874: please increase limit on kernel command line length

[John Morrissey <jwm@horde.net>]

Package: linux-2.6
Version: 2.6.20-3
Severity: wishlist

Please increase the limit on the kernel's command line length. We're using
debian-installer's preseed support for performing unattended installations
and it's difficult to fit the necessary preseed information into 256 bytes
(this is on i386).

For example, here is the command line we're using to perform installations
via serial console:

append DEBIAN_FRONTEND=text initrd=e/i locale=en_US console-keymaps-at/keymap=us netcfg/no_default_route=true netcfg/dhcp_timeout=90 url=http://server:elided@example.com/install/etch.cfg console=ttyS1,57600n81 --

The preseed URL has been obscured, but the full length is ~230 characters.
We've moved everything we possibly can out of the kernel command line and
into the preseed file, but some things must still be on the command line,
such as network configuration (d-i must obviously set up the network before
it can retrieve the preseed file over it :-) We've even taken to making
single-character symlinks for the initrd to squeeze a few more bytes out.

COMMAND_LINE_SIZE (in include/asm-*/setup.h) is set per arch, but I'm not
sure what arch-related constraints there are to increasing its size. Some
arches have length limits as high as 1024 or even 4096 bytes. 512 would be a
great benefit, and 1024 is probably more than anyone would need for
preseeding.

-- System Information:
Debian Release: 4.0
  APT prefers stable
  APT policy: (500, 'stable')
Architecture: i386 (i686)
Shell:  /bin/sh linked to /bin/bash
Kernel: Linux 2.6.18-4-686
Locale: LANG=C, LC_CTYPE=C (charmap=ANSI_X3.4-1968)