Created attachment 19655
Xorg.0.log

I'm forwarding this bug report from a Ubuntu user.

The user has a 19" Sony Trinitron E400 Monitor that reports invalid EDID.  The recommended resolution for this monitor is 1280x1024, but it defaults to 1280x768.  The user has tested with stock xorg.confs as well as hand-customized configurations.  He is attempting to use an ATI RV200 QW [Radeon 7500] card; the motherboard has an onboard SiS630/730 card; both graphics cards are showing invalid EDID, so we're guessing it's the monitor that's buggy, and must need an xserver quirk.

19" Sony Trinitron E400 Information:
Horizontal Freq. 30-96 kHz
Vertical Freq. 48-120 Hz

ATI card:
01:00.0 VGA compatible controller [0300]: ATI Technologies Inc Radeon RV200 QW [Radeon 7500] [1002:5157] (prog-if 00 [VGA])
	Subsystem: ATI Technologies Inc Radeon 7500 [1002:013a]

qsomi@qsomi-desktop:~/Desktop$ sudo get-edid > edid.dat
get-edid: get-edid version 1.4.1

 Performing real mode VBE call
 Interrupt 0x10 ax=0x4f00 bx=0x0 cx=0x0
 Function supported
 Call successful

 VBE version 200
 VBE string at 0x11110 "ATI RV200"

VBE/DDC service about to be called
 Report DDC capabilities

 Performing real mode VBE call
 Interrupt 0x10 ax=0x4f15 bx=0x0 cx=0x0
 Function supported
 Call successful

 Monitor and video card combination does not support DDC1 transfers
 Monitor and video card combination supports DDC2 transfers
 0 seconds per 128 byte EDID block transfer
 Screen is not blanked during DDC transfer

Reading next EDID block

VBE/DDC service about to be called
 Read EDID

 Performing real mode VBE call
 Interrupt 0x10 ax=0x4f15 bx=0x1 cx=0x0
 Function supported
 Call failed

The EDID data should not be trusted as the VBE call failed
qsomi@qsomi-desktop:~/Desktop$ xxd edid.dat
0000000: ffa2 00ff ffff ff00 4dd9 9003 f24a 7b00 ........M....J{.
0000010: 2f0a 0102 0e25 1b96 eb0c c9a0 5747 9b27 /....%......WG.'
0000020: 1248 4cff ff80 c280 a94f 8159 814f 7159 .HL......O.Y.OqY
0000030: 6159 4559 3159 863d 00c0 5100 3040 40a0 aYEY1Y.=..Q.0@@.
0000040: 1300 6008 1100 001e 0000 00fd 0030 781e ..`..........0x.
0000050: 601e 000a 2020 2020 2020 0000 00fc 0053 `... .....S
0000060: 4f4e 5920 4350 442d 4534 3030 0000 00ff ONY CPD-E400....
0000070: 0038 3038 3031 3134 0a20 2020 2020 00d8 .8080114. ..
http://launchpadlibrarian.net/17528516/edid.dat


With the onboard SiS 630/730:

qsomi@qsomi-desktop:~/Desktop$ sudo get-edid > edid.dat
get-edid: get-edid version 1.4.1

 Performing real mode VBE call
 Interrupt 0x10 ax=0x4f00 bx=0x0 cx=0x0
 Function supported
 Call successful

 VBE version 300
 VBE string at 0x11110 "SiS"

VBE/DDC service about to be called
 Report DDC capabilities

 Performing real mode VBE call
 Interrupt 0x10 ax=0x4f15 bx=0x0 cx=0x0
 Function supported
 Call successful

 Monitor and video card combination does not support DDC1 transfers
 Monitor and video card combination does not support DDC2 transfers
 0 seconds per 128 byte EDID block transfer
 Screen is not blanked during DDC transfer

Reading next EDID block

VBE/DDC service about to be called
 Read EDID

 Performing real mode VBE call
 Interrupt 0x10 ax=0x4f15 bx=0x1 cx=0x0
 Function supported
 Call failed

The EDID data should not be trusted as the VBE call failed
qsomi@qsomi-desktop:~/Desktop$ xxd edid.dat
0000000: ffa2 00ff ffff ff00 4dd9 9003 f24a 7b00 ........M....J{.
0000010: 2f0a 0102 0e25 1b96 eb0c c9a0 5747 9b27 /....%......WG.'
0000020: 1248 4cff ff80 c280 a94f 8159 814f 7159 .HL......O.Y.OqY
0000030: 6159 4559 3159 863d 00c0 5100 3040 40a0 aYEY1Y.=..Q.0@@.
0000040: 1300 6008 1100 001e 0000 00fd 0030 781e ..`..........0x.
0000050: 601e 000a 2020 2020 2020 0000 00fc 0053 `... .....S
0000060: 4f4e 5920 4350 442d 4534 3030 0000 00ff ONY CPD-E400....
0000070: 0038 3038 3031 3134 0a20 2020 2020 00d8 .8080114. ..
http://launchpadlibrarian.net/17528747/edid.dat

Example tested with xserver 1.4.99.906-x:
xorg.conf:  http://launchpadlibrarian.net/16991298/xorg.conf
Xorg.0.log: http://launchpadlibrarian.net/16991306/Xorg.0.log
http://launchpadlibrarian.net/16991342/xrandr.txt