[MinnowBoard] no suitable video mode found booting in blind mode

[Ken Tait]

John,

The power supply issue is pretty straight forward to me since I deal 
with this all the time. The Wallwarts under load have a slow rise time. 
This tends to fool reset monitors and comparators and results in things 
not sequencing right. They work, but don't all start at the right time 
as a simple explanation. You get around this by using a larger supply, 
adding a switch first, adding some capacitance right at the input 
jack..not too much as this can make it worse.

I had alot of trouble with the minnowboard and just got tired of dealing 
with it for now since there were no lures, but to summarize what i found:

1.    It didn't seem to like a particular monitor I tried. It was a 
tv/vga/hdmi monitor. The problem was that it was feeding it before it 
was ready and somehow thought it wasn't there, so it locked out this 
port and defaulted to the serial port. If I powered up the monitor 
first, let it sit, then the minnow it would come up.
The minnow clearly comes up very fast compared to everything around it.

2.    It didn't always boot cleanly from the sd card, screen messages 
clearly show that it blew past this. This again is a speed issue. This 
particular card probably took a few more MS to initialize than the bios 
allowed. SD cards too are all over the map on spi speed and startup delays.
Using these same cards on a 800mhz board with angstrom image always 
works fine for comparison.

3.    I noticed the same thing when I plugged in a USB WIFI, it was hit 
or miss as to whether the bios saw it first time. If if came up at all 
and responded to a keyboard, a manual shutdown and restart always worked 
without un-plugging the stick..

4.    I have 1 keyboard/mouse pad combo,(GearHead), it REFUSED to see it 
at all. This works fine on 4 other Linux putups I have.Ii think I 
changed the driver in the original image to fix this...can't remember.

All in all, it's clear to me most of the issues are 5V loading and bios 
delay issues.

I don't know how the bios is manufacturing delays, but if you are using 
software delays(bad.bad.bad practice) then they probably are not the 
actual time you think they are or the compiler is optimizing them out. 
You must explicitly tell the compiler with #pragmas to not do this. I 
experience this all the time .

If i get more time, I'll try and get the bios code and take a look at it 
and see if I spot something suspect. Pretty swamped right now...

Ken