Switching between HDMI and S-Video using the Lucid Image?

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1

Hey Everyone,
I have Lucid installed from the image on http://elinux.org/BeagleBoardUbuntu.
I was wondering how I can switch to S-Video? Do I have to make a new
image? The documentation on http://elinux.org/BeagleBoardUbuntu#S-Video
says I have to change the boot args but I'm not quite sure how to do
that. In /boot/uboot/ I have boot.cmd which I could edit, but there's
also boot.ini which looks like a slightly encoded version of boot.cmd,
so I figured it's probably best not to just edit boot.cmd.

in /boot/uboot/tools I see rebuild_uinitrd.sh which seems promising,
but I'm not quite sure what it's doing either.

Does anyone have any pointers on how to make the switch?

Thanks!
Gabe

2

Oh, and I've got the xM, sorry for omitting that.

Gabe

3

You don’t need to rebuild anything. The bootloader reads boot.ini, but this file is generated from boot.cmd using mkimage.

Maybe it would be easier to change to S-Video using another approach.

Connect a serial cable and configure a terminalto 115200,8,N,1

After boot, press some key to stop autoboot.

Type:

  1. setenv defaultdisplay=tv
  2. saveenv
  3. boot (or reset)

Done, now S-Video is your default display on every boot!

4

Hmmm, now I noticed that you are using ubuntu. The procedure could be a little different, depending on the environment of your bootloader. Anyway, just set the coorect bootargs to the kernel and you’ll get S-Video.

Rafael

5

I was playing with the validation images this past weekend and tried
this, but without saving the env changes. In either case (with or
without setting defaultdisplay) the S-Video output was pretty bad - wavy
or pixelated display and (based on the sample video, assuming its in
color) no color. The color bars get displayed but had jaggiies at boot
but disappear when I ran /usr/bin/svideo.

Looking at fbset (I think - maybe it was something else, I was just
experimenting with a bunch of ideas) it looked as though the S-Video was
set for PAL and not NTSC. I haven't yet identified the exact steps to
verify NTSC and get decent S-Video output.

Do you have to saveenv or can you just boot immediately. I realize the
setting won't carry over to a reboot but I don't think saveenv shouldn't
be necessary to test a setting, correct?

I still have to read through the DSS docs more carefully. Perhaps what
I need is in there.

6

Hi Gabe,

you were looking in the exact right place..

boot.cmd in /boot/uboot/ is there for you to modify.

Then from /boot/uboot/ just call "./tools/boot_scripts.sh" and it'll
rebuild your boot.scr for next boot..

The s-video settings from here should work...

http://elinux.org/BeagleBoardUbuntu#S-Video

NTSC is ready to go, but Pal needs some documentation..

Regards,

7

Thanks Robert!
I changed omapfb.mode=dvi:${dvimode} to omapfb.mode=tv:ntsc
omapdss.def_disp=tv, ran boot_scripts.sh, and I checked that the other
two files (boot.ini and boot.scr) and they now seem to contain the
right bootargs. Unfortunately now I get nothing from either the HDMI
port or the S-Video port. I'm using an S-Video to composite adapter
connected to a Dell 23" LCD which has Composite in. Do you have any
suggestions for figuring out what's going on? (I'm able to connect
via the serial port) You can see the complete boot sequence here
where it has the correct tv:ntsc and tv args for omapfb.mode and
omapdss.def_disp: http://pastebin.com/AuJvQULK

Thanks!
Gabe

8

I'm using the validation images and wanted to try these out. I booted,
interrupted u-boot and made the changes to the bootargs. I loaded
uImage.bin from the SD card and booted. But this boot failed to mount
the ramdisk. I tried variations on this and they all failed to mount
the rootfs. The only method I was able to get working is the default
boot process, re: just type "boot" from u-boot's command line without
editing any env vars. I'm obviously not understanding the boot process.

So I was wondering: are there two u-boot images, one in ROM and one on
the SD card? Is the latter loaded by the former and the latter the one
that is loading the boot.scr, making my changes from the u-boot command
line irrelevant? I'm a little confused by this boot process as in the
past I've always flashed u-boot to a ROM or NOR/NAND and had it boot the
kernel via flash, nfs, or whatever. The x-loader is also a little
confusing to me - what exactly is its purpose? I thought I'd read that
the x-loader is in ROM and loads a minimal u-boot that then loads the
u-boot from the SD card that then loads the boot.scr before loading the
kernel. Is that how this works?

Finally, the boot.scr is generated by the build process for Angstrom,
correct? I haven't read the recipes yet but was wondering which script
from recipes/angstrom/angstrom-uboot-scripts is being used to generate
normal_revc_v3.src.

Thanks for any pointers.

9

Just an update from my end (sorry Michael, I'm not running Angstrom so
I can't help there).

Turns out the problem was using the S-Video to Composite wire.
Running straight S-Video seems to work fine (in case anyone else ends
up reading this whole thread). I'll be starting a new thread on why
it doesn't work with the adapter :slight_smile:

Gabe