First, thanks for 0.99.25.1. That fixed the performance issues I was
having on my radeon mobility SBC system.
I'm now up to working on getting TV-Out going. I realize that this is
usually a very thorny issue, but I'm hoping that someone might still
have some good advice.
On this SBC, the BIOS has an option to make TV-Out the primary display.
When I turn that option on, the bios stuff shows on the Composite video
output, and a little bit of grub and linux start up stuff show up as
well (most of it is directed towards ttyS0).
However, when my application starts, I loose sync. My application
originally was trying to use 640x480. I want NTSC output. I'd like
720x486 output but really 640 wide is good enough and 6 extra blank
lines wouldn't hurt either. I'm just trying to get 640xSomething
working for now. I figure that since I got it this far with the dreaded
ATI that perhaps it is worth continueing work on.
Anyway I brought out an osciliscope and a waveform monitor. It appears
that the video output is still active and trying to make pictures, but
that the timing is wrong.
I started with this in fb.modes:
mode "640x480-60"
# D: 25.175 MHz, H: 31.469 kHz, V: 59.94 Hz
geometry 640 480 640 480 8
timings 39722 48 16 33 10 96 2
endmode
That wouldn't lock either horizontal or vertical. Adding bcast true and
laced true didn't significantly improve. However, I notice that 39722
pico seconds times 96 pixels is only 3.8us, and the horizontal sync
length is supposed to be 4.7us, so I changed that value to 118. Now the
horizontal sync will lock. Also, the NTSC standard calls for 3 lines of
VBI, so I changed that as well. Next, I changed it from 480 to 486
lines. Now when I start the program I get horizontal lock, but not
vertical lock. I also noticed that during startup directfb prints to
the console:
vStart = 496, vEnd = 499, vTotal = 532
So, I guess there is trouble here with vTotal not being 525.
Anyway, if I adjust the frame buffer size or the top or bottom margins
it doesn't really help. If I have less than 525 lines total, the
waveform monitor will lock to the vertical, but the monitor still won't
lock.
At this point, this is my fb.modes entry:
mode "640x486-60"
# D: 25.175 MHz, H: 31.469 kHz, V: 59.94 Hz
geometry 640 486 640 486 8
timings 39722 48 16 17 19 118 3
bcast true
laced true
endmode
BTW, if I grab this:
mode "640x480-60"
# H: 31 kHz, V: 59 Hz
geometry 640 480 640 480 4
timings 34920 64 96 30 9 112 2
endmode
from a file (fb.modes.NTSC) in ubuntu, I get perhaps the closest in that
I can recognize the "picture" on the screen better, but things are still
badly askew. It is all slanted and the right part of the image is on
the left of the screen and vice versa. DirectFB reports only 521 lines
for vTotal with this.
I'm a bit disappointed in the lack of examples for NTSC resolutions that
I've been able to find. The fb.modes.NTSC doesn't seem to be
particularly NTSC related.
As I can't think of anything else that is likely to be helpful at the
moment, I guess I'll hit send.
--
Joshua D. Boyd
[EMAIL PROTECTED]
http://www.jdboyd.net/
http://www.joshuaboyd.org/
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