[mythtv-users] Help -- why suddenly dramatically improved TV-out w/onboard GF4 MX ??

Joseph A. Caputo jcaputo1 at comcast.net
Tue Jan 17 16:10:47 UTC 2006

...not that I'm complaining!

I've complained before on this list that the TV-out from my onboard GF4 
MX 440 (Chaintech 7NIF2 mobo) was abysmal compared to my old (now dead) 
LeadTek GF4 MX 420 AGP card.  Until recently, I blamed it on the fact 
that the mobo revision I got contained a new TV encoder chip (NV18) 
compared to the NV17 chip that was on my old card and previous 
revisions (like Jarod's, IIRC) of the Chaintech 7NIF2.

Well, apparently I was wrong.

A few months ago, I came home from work one day to find a stunningly 
clear TV-out coming from my Myth box!  I tried poking around, but 
couldn't figure out why, and my wife accidently rebooted the box before 
I could figure it out.  After the reboot, my crappy TV-out was back.  
But it got me thinking...

Several weeks later, it happened again, but this time I was able to 
piece together what happened.  It seems that my wife tends to reboot 
the box sometimes because she can't remember which is the CD eject 
button (granted, the pwr & reset buttons on the Antec Aria just *beg* 
to be pressed, compared to the CD eject button which is, well... rather 
plain... still, <rant>how could you *not* figure it out after the third 
accidental reboot???</rant>

Anyway, what happend was this:  I have my Myth setup going into a 3-way 
A/V switch (with my DVD player & VCR).  At this particular time, the 
Myth box was rebooted while the switch was in the 'DVD' position; thus 
the video hardware did not detect the TV connected... something about 
that situation caused the TV-out to be crystal-clear.

Of course, the first thing I tried was to add "IgnoreEDID" "1" to my 
xorg.conf, but that didn't help.  So, started X both with and without 
the TV connected, hoping to see some important differences... and the 
only differences were that the last 10 lines of the logfile repeated.  
That in itself is probably significant.  So, for the "bad" TV-out, the 
last 10 lines of Xorg.0.log are:

(WW) Open APM failed (/dev/apm_bios) (No such file or directory)
(II) NVIDIA(0): Setting mode "800x600"
(II) Loading extension NV-GLX
(II) NVIDIA(0): NVIDIA 3D Acceleration Architecture Initialized
(II) NVIDIA(0): Using the NVIDIA 2D acceleration architecture
(II) NVIDIA(0): v4l[/dev/video0]: using hw video scaling [YUY2].
(==) RandR enabled
(II) Initializing extension GLX
(II) USB Mice: ps2EnableDataReporting: succeeded
Could not init font path element /usr/X11R6/lib/X11/fonts/CID/, removing 
from list!

For the "good" TV-out, those 10 lines are repeated *exactly* in the next 
10 lines.

The funny thing is, it almost looks like for the "bad" TV-out, only one 
video head is being properly initialized, while for the "good" TV-out, 
both heads are being initialized (or the driver is just performing the 
initialization twice).  The thing is, I would have expected the TV-out 
to *not* be initialized properly if it wasn't connected, but apparently 
the opposite is happening.  Weird.  This is Nvidia driver 7174 on an 
FC3 box, BTW.

So, my question is:  can anyone help figure out exactly *why* this is 
happening, and more importantly, how to fix it so that I don't have to 
disconnect my TV every time X restarts on my Myth box in order to get a 
good picture?

Here are the relevant lines from my xorg.conf:

Section "Monitor"
        Identifier      "TV"
        VendorName      "Philips"
        HorizSync       30.0 - 50.0
        VertRefresh     59.94
        DisplaySize     203 152
        ModeLine "640x480NTSC"  28.195793  640 656 658 784  480 520 525 
        ModeLine "720x480NTSC"  27.5  720 744 800 872  480 483 485 525
        ModeLine "800x600NTSC"  38.769241  800 812 814 880  600 646 649 

Section "Device"
        Option "SWCursor" "0"
        Identifier  "Card0"
        Driver      "nvidia"
        VendorName  "NVidia"
        BoardName   "0x0172"
        Option      "HWCursor" "on"
        Option      "NoLogo" "on"
        Option "NvAGP" "1"
        Option "DigitalVibrance" "33"
        Option "CursorShadow" "0"
        Option "TwinView" "1"
        Option "SecondMonitorHorizSync" "30-50"
        Option "SecondMonitorVertRefresh" "60-60"
        Option "TwinViewOrientation" "Clone"
        Option "ConnectedMonitor" "tv"
        Option "TVStandard" "NTSC-M"
        Option "MetaModes" "800x600NTSC,800x600NTSC"
        Option "TVOverScan" "0.7"
        Option "DigitalVibrance" "50"
        Option "IgnoreEDID" "1"

Section "Screen"
        Identifier "TV-0"
        Device     "Card0"
        Monitor    "TV"
        DefaultDepth    24

        SubSection "Display"
                Modes "800x600NTSC" "720x480" "640x480" "400x300" 
                Depth 24

If nothing else, at least maybe this will help someone else coax a good 
TV-out picture from their board!


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