XWindows Geometry - LCD TV

TrevorBradley · 10-04-2007, 04:59 PM

I own an Olevia 337 LCD TV, which is hooked up to my HTPC. It's been working great for MythTV, but in XWindows/KDE or Mame there's a subtle problem. The outside pixels of the display aren't displayed, and perhaps a rectangle of pixels around the desktop image, maybe 5-10 pixels at most, are missing.

Now I'm guessing this is just something I have to deal with with my DVI-HDMI connection from my box (GeForce 6200 onboard) to the TV set and I don't believe there's some sort of hardware or driver "fix". (If there is, I'd love to hear it. It's particularly annoying during boot.. I can't even read the leftmost character of the boot text!)

What I would like to do is to trick XWindows so that it doesn't display anything in the outside pixels, say, perhaps rendering 1350x1014 on the 1360x1024 display, with a "black box" 5 pixels thick surrounding it.

Is there a way I can modify xorg.conf to accomplish this?

Any other information on missing pixels or an overly large image on LCD TVs would be appreciated.

Thanks in advance,

Trevor Bradley
Surrey, BC

GrapefruiTgirl · 10-04-2007, 05:12 PM

In the MetaModes line for that display, try something along these lines:

Option "MetaModes" "DFP:1360x1014 @ 1350x1014 +5+5"

Note, I have only given the data for ONE display, so if you have TWO, apply this idea to the relevant one.
Note: You must use 'MetaModes' for this type of 'virtual size' adjustment.

the +5+5 recenters the display to account for the missing 10 px per axis.

NOTE - this won't fix anything during boot, ONLY within X environment. For the boot screen, you need to adjust your framebuffer resolution, and/or check your TV's OSD for settings you can adjust to fix the display.

TrevorBradley · 10-04-2007, 05:48 PM

Doesn't seem to do anything... :| Where should this option live?

GrapefruiTgirl · 10-04-2007, 06:08 PM

It would usually live in the 'Screen' section, like so:

Code:

Section    "Screen"
Identifier "Screen0"
Device     "nVidia1"
Monitor    "KDS0" #& IBM0
DefaultDepth 16
Option     "RenderAccel" "On"
Option     "HWcursor" "On"
Option     "DamageEvents" "True"
Option     "ConnectedMonitor" "CRT-0,CRT-1"
Option     "twinVieworientation" "CRT-1 Rightof CRT-0"
Option     "metamodes" "CRT-0:1600x1200,CRT-1:1280x1024 @ 1600x1200"
EndSection

TrevorBradley · 10-04-2007, 08:29 PM

Hmm, I'm thikning the Monitor ("CRT-0") needs to be defined. My screen section looks pretty boring (blame NVIDIA's installer)

Code:

Section "Screen"

# If your card can handle it, a higher default color depth (like 24 or 32)
# is highly recommended.
#   DefaultDepth 8
#   DefaultDepth 16
#   DefaultDepth 32

# "1024x768" is also a conservative usable default resolution.  If you
# have a better monitor, feel free to try resolutions such as
# "1152x864", "1280x1024", "1600x1200", and "1800x1400" (or whatever your
# card/monitor can produce)
    Identifier     "Screen 1"
    Device         "VESA Framebuffer"
    Monitor        "My Monitor"
    DefaultDepth    24
    SubSection     "Display"
        Depth       8
        Modes      "1024x768" "800x600" "640x480"
    EndSubSection
    SubSection     "Display"
        Depth       16
        Modes      "1024x768" "800x600" "640x480"
    EndSubSection
    SubSection     "Display"
        Depth       24
        Modes      "1360x768" "1024x768" "800x600" "720x480"
    EndSubSection
    SubSection     "Display"
        Depth       32
        Modes      "800x600"
    EndSubSection

EndSection

GrapefruiTgirl · 10-04-2007, 08:39 PM

CRT-0, when used in the fashion that it is used in my example (which is from my xorg.conf file, does not need to be defined. It automatically refers to the first CRT found connected to the computer.

That IS a bland Screen section however

heh heh

EDIT - However, if you are using a HDTV or some sort of flat panel display, then CRT-0 will probably cause problems. Other options are DFP- and TV- but check the man page of xorg.conf, and also I highly recommend the nVidia README documentation, which is contained within the driver installer, or can be viewed on nvidia.com

TrevorBradley · 10-06-2007, 12:24 AM

No Dice... The only thing the MetaModes setting did was that positive values of +30+30 *increased* the size of the screen... negative values had no effect, changing the resolutions had no effect (unless I changed both resolutions to something like 1024x768, then the resolution changed, but still with underscan issues. I even tried playing with the TVOverScan Option.. no change...

Are there other utils for configuring xorg.conf that allows you to change these settings? I hear nvidia-settings has a slider, but I couldn't see it (the fonts were super tiny too, but that's a different issue).

I think I'm gonna give up for now unless I can get some more info...

TrevorBradley · 10-06-2007, 03:43 PM

I've had a chance to play with this further. Almost all the font settings seem to be there to increase the size of your desktop, not decrease it. Even the docs, which suggested fixing the virtual screen size, didn't seem to help. I'm stumped.

TrevorBradley · 10-06-2007, 06:06 PM

Got it! Though XWindows didn't have anything to do with it.

My Olevia HDTV has a hidden feature called "Cropping", default set to "On" which causes the underscan. Changed the setting, everything's fine now.

It's likely my Digital TV will be messed now, but who watches that?

GrapefruiTgirl · 10-06-2007, 06:11 PM

Awesome! Gotta like them 'hidden features'