945GM HDTV out and related issues

Hamish Moffatt hamish at cloud.net.au
Thu May 24 08:06:44 PDT 2007

I've got a 945GM chipset and I'm trying to get 1080i at 50Hz mode working
using the latest (from git) xserver-xorg-video-intel.

The card is connected via component output to the TV, and there are no
other ports connected (VGA/DVI).

I have this almost working; it seems I am just missing a 1920x1080 50Hz
modeline acceptable to X?

Some observations;

1. I always get the following in the log, and I can't find a solution.
It also appears that half of the log gets repeated. I suspect this is
due to dual head, which I'm not using?

(WW) intel: No matching Device section for instance (BusID PCI:0:2:1) found

lspci shows

00:02.0 VGA compatible controller: Intel Corporation Mobile 945GM/GMS/940GML Express Integrated Graphics Controller (rev 03)
00:02.1 Display controller: Intel Corporation Mobile 945GM/GMS/940GML Express Integrated Graphics Controller (rev 03)

2. I set Option "LinearAlloc" "6144" in Section Driver, but the log
always says it is not used. However it may be in repeated section of the
log (as above).

3. I put Option "TV Format" "1080i at 50Hz" in the Monitor section, which
despite being "not used" according to the log does change the available
modes according to xrandr.

So it seems that 1920x1080 at 50Hz would now work if I had a suitable
modeline? I have one courtesy Google, but the log says "bad mode
clock/interlace/doublescan". That same modeline is accepted when I use
VGA output instead, although the TV won't really sync to it.
What makes it unacceptable for TV output, but acceptable otherwise?

ModeLine "1920x1080_50i" 74.250 1920 2448 2492 2640 1080 1148 1158 1124 interlace +hsync +vsync

1080i at 60Hz mode worked (with a different modeline) although it flickered
very badly. I suspect the modeline needs some adjustment.  1080i at 60Hz 
over VGA with the above modeline comes up OK (into the same TV). 

4. Alternatively I have tried 1280x720p mode, which comes up but the display is 
badly offset to the left of the screen. That is, the default X
background ends at about 1/4 of the way across the TV from the left, and
the rest is all black. Can this be adjusted? I didn't set a modeline,
but used a default one.

5. Having put in a Modeline for 720p, and listed only that mode in the
Modes section in the Screen, X is still using a bunch of other modes
like 1280x800 and 1280x768. How do I disable those?

6. With only VGA connected, the driver seems to think TMDS-1 is also
connected and links it to pipe B. Is this harmful? I tried Option
"MonitorLayout" "CRT,NONE" and nothing changed.

Configuration and log from my main attempt at 1080i at 50Hz attached.

Sorry this email became a bit of a ramble. Is there a better forum for
user-type issues than this?

Hamish Moffatt VK3SB <hamish at debian.org> <hamish at cloud.net.au>
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# xorg.conf (xorg X Window System server configuration file)
# This file was generated by dexconf, the Debian X Configuration tool, using
# values from the debconf database.
# Edit this file with caution, and see the xorg.conf manual page.
# (Type "man xorg.conf" at the shell prompt.)
# This file is automatically updated on xserver-xorg package upgrades *only*
# if it has not been modified since the last upgrade of the xserver-xorg
# package.
# If you have edited this file but would like it to be automatically updated
# again, run the following command:
#   sudo dpkg-reconfigure -phigh xserver-xorg

Section "Files"

Section "InputDevice"
	Identifier	"Generic Keyboard"
	Driver		"kbd"
	Option		"CoreKeyboard"
	Option		"XkbRules"	"xorg"
	Option		"XkbModel"	"pc104"
	Option		"XkbLayout"	"us"

Section "InputDevice"
	Identifier	"Configured Mouse"
	Driver		"mouse"
	Option		"CorePointer"
	Option		"Device"		"/dev/input/mice"
	Option		"Protocol"		"ImPS/2"

Section "Device"
	Identifier	"Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller"
	Driver		"intel"
	BusID		"PCI:0:2:0"
	Option "LinearAlloc" "6144"
	Option "ModeDebug" "Yes"

Section "Monitor"
	Identifier	"TV"
	Option "TV Format" "1080i at 50Hz"
	ModeLine "1920x1080" 74.250 1920 2008 2052 2200 1080 1084 1094 1124 interlace +hsync +vsync

Section "Screen"
	Identifier	"Default Screen"
	Device		"Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller"
	Monitor		"TV"
	DefaultDepth	24
	SubSection "Display"
		Depth		24
		Modes		"1920x1080" "1280x720"
		Virtual 2048 1200

Section "ServerLayout"
	Identifier	"Default Layout"
	Screen		"Default Screen"
	InputDevice	"Generic Keyboard"
	InputDevice	"Configured Mouse"
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