[NBLUG/talk] How to configure Xorg for a 1080p display?

[Lincoln Peters]

And now for something completely different...


I'm trying to use a somewhat older computer (a Compaq with a Pentium III 
processor and 128MB of RAM) to control a 1080p HDTV that has a VGA input.  
I've installed Ubuntu Linux on the computer, and it defaulted to a resolution 
of 1360x1024, with me having to move the mouse to the top and bottom edges to 
reveal them (i.e. the virtual screen is taller than the actual screen).  It's 
also far lower than the TV's native resolution of 1920x1080,

I've tried to edit xorg.conf to make it run at 1920x1080 resolution (the TV's 
native resolution), but it still wants to run at 1360x1024.  It's hard to be 
sure exactly which of the lines from the Xorg log are relevant, but here are 
a few that look like they might be:

(II) I810(0): Monitor name: SONY TV
(II) I810(0): EDID (in hex):
...
(II) I810(0): Using EDID range info for horizontal sync
(II) I810(0): Using EDID range info for vertical refresh
(II) I810(0): Printing DDC gathered Modelines:
...
(II) I810(0): Modeline "1920x1080"  148.50  1920 2008 2052 2200  1080 1084 
1089 1125 +hsync +vsync
...
(--) I810(0): Chipset: "i810e"
(--) I810(0): Linear framebuffer at 0x44000000
(--) I810(0): IO registers at addr 0x40200000
(II) I810(0): Kernel reported 24064 total, 1 used
(II) I810(0): I810CheckAvailableMemory: 96252k available
(==) I810(0): Will alloc AGP framebuffer: 8192 kByte
(==) I810(0): Using gamma correction (1.0, 1.0, 1.0)
(II) I810(0): SONY TV: Using hsync range of 30.00-80.00 kHz
(II) I810(0): SONY TV: Using vrefresh range of 55.00-65.00 Hz
(II) I810(0): Clock range:   9.50 to 136.00 MHz
...
(II) I810(0): Not using driver mode "1920x1080" (bad mode 
clock/interlace/doublescan)
(II) I810(0): Not using mode "1920x1080" (no mode of this name)
...
(II) I810(0): Not using default mode "1400x1050" (width too large for virtual 
size)
(II) I810(0): Not using default mode "1440x900" (width too large for virtual 
size)
(--) I810(0): Virtual size is 1360x1024 (pitch 2048)


I can't find anything in the logs to prove this, but I'm reasonably sure that 
the physical display is running at a resolution of 1360x768, since it's the 
only resolution with 1360 columns natively supported by the TV.

Any thoughts as to what I might be missing?  The documentation for the TV 
clearly states that it can run at 1920x1080 over the VGA port, with a 
horizontal frequency of 67.5kHz and a vertical frequency of 60Hz


By the way, I also tried it with Knoppix, and the best I could get was a 
screen resolution of 1440x1050, and I could not get anything other than a 4:3 
aspect ratio (the HDTV is 16:9).  In every case under Knoppix, the left and 
right sides of the screen were unused, to yield a 4:3 aspect ratio.


-- 
Lincoln Peters		<sampln at sbcglobal.net>

Science is to computer science as hydrodynamics is to plumbing.