Cannot get DVI signal

```
I have a BeagleBoard C4 and followed the build and setup instructions using the
manifest rowboat-eclair.xml. Everything compiled just fine, Graphics SGX SDK
installation went OK, sdcard with kernel and system image created successfully.
When starting from sdcard:

Kernel is up and running, Android boots up but I cannot get any DVI ouput. In
the kernel log I see this:

---------------------------------------------------------
[...]
<6>VFP support v0.3: implementor 41 architecture 3 part 30 variant c rev 1
<6>fbcvt: 1280x1024@60: CVT Name - 1.310M4-R
<4>regulator_init_complete: incomplete constraints, leaving VDVI on
<4>regulator_init_complete: incomplete constraints, leaving VDAC on
<4>drivers/rtc/hctosys.c: unable to open rtc device (rtc0)
<3>omapdss DPI error: display already enabled
<4>omap_vout omap_vout: 'dvi' Display already enabled
<3>omapdss DPI error: display already enabled
<4>omap_vout omap_vout: 'dvi' Display already enabled
<6>omap_vout omap_vout: Buffer Size = 3686400
<6>omap_vout omap_vout: : registered and initialized video device 0
<6>omap_vout omap_vout: Buffer Size = 3686400
<6>omap_vout omap_vout: : registered and initialized video device 1
[...]
---------------------------------------------------------

I tried all the boot args below with no success.

---------------------------------------------------------
setenv bootargs 'mem=128M androidboot.console=ttyS2 console=tty0
console=ttyS2,115200n8 root=/dev/mmcblk0p2 rw init=/init rootwait
omap-dss.def_disp=dvi omapfb.video_mode=720x480MR-16@60'

setenv bootargs 'mem=128M androidboot.console=ttyS2 console=tty0
console=ttyS2,115200n8 root=/dev/mmcblk0p2 rw init=/init rootwait
omapfb.mode=dvi:1024x768MR-24@60 omapfb.vram=0:2M,1:4M'

setenv bootargs 'mem=128M androidboot.console=ttyS2 console=tty0
console=ttyS2,115200n8 root=/dev/mmcblk0p2 rw init=/init rootwait
omapdss.def_disp=dvi omapfb.mode=dvi:1280x1024MR-16@60 vram=12M
omapfb.vram=0:4M,1:4M,2:4M'
---------------------------------------------------------

The thing is that when in U-Boot mode, I can see the orange background (DVI)
and the color bars in S-Video output but as soon as the kernel starts the DVI
output goes black.

Have I missed anything? Is there any problem with the kernel or the DVI
drivers?
```

Original issue reported on code.google.com by `Edfel...@gmail.com` on 14 Oct 2010 at 7:52

Start with the supplied kernel log and the three U-Boot boot-argument examples; compare DVI behavior before and after the kernel starts. Trace the OMAP DSS/DVI and omap_vout initialization mentioned in the log, then reproduce the issue from the SD card. Done means identifying the relevant kernel, driver, or configuration cause and restoring DVI output.

Written by the indexing model from the issue text.