what happens when u-boot initrd address and "initrd=" address disagree?

[Robert P. J. Day]

(note: actually a u-boot question but i don't want to subscribe to a
whole new list to ask one question and i'm sure someone here knows the
answer.)

i was torturing robert nelson yesterday regarding his ubuntu image
builder and ran across the following oddity. in addition to the
second address arg to bootm being the address of the initrd image in
RAM, i've seen examples where the bootargs line *also* has an initrd=
setting, like here:

http://processors.wiki.ti.com/index.php/Initrd

where you can read about 1/2 way down the page:

UBOOT # setenv bootargs ... root=/dev/ram0 rw initrd=0x87000000,8M
UBOOT # setenv bootcmd cp.b 0x2200000 0x87000000 0x<filesize>; bootm
UBOOT # saveenv

where you can see "initrd=" is part of the bootargs.

on the other hand, robert's boot.cmd for his ubuntu ARM image
contains:

setenv bootcmd 'fatload mmc 0:1 0x80300000 uImage; fatload mmc 0:1
0x81600000 uInitrd; bootm 0x80300000 0x81600000'
setenv bootargs console=${console} ${optargs} root=${mmcroot}
rootfstype=${mmcrootfstype} vram=${vram}
omapfb.mode=${defaultdisplay}:${dvimode}
omapdss.def_disp=${defaultdisplay}

where the bootargs has no initrd= setting, but the bootm command
itself has a second arg that obviously represents the initrd.

so i just want to clarify, is there any problem with having the
initrd reference in both places? is it acceptable to put it in
*either* place? and what happens if you put it in both places and the
address differs?

this is all being done on a panda ES, even though it's clearly a
general u-boot question.

rday

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Robert P. J. Day Ottawa, Ontario, CANADA
http://crashcourse.ca

Twitter: http://twitter.com/rpjday
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