Ubuntu
linux-restricted-modules-2.6.15 package

xorg / fglrx doesn't recognise monitor modes correctly

Bug #22122 reported by sebastiaan on 2005-09-20

This bug report is a duplicate of: Bug #3731: Xorg resolution falling back to 640x480 and/or 800x600 when h/v freqs incorrect. Edit Remove

Affects		Status	Importance	Assigned to	Milestone
	linux-restricted-modules-2.6.15 (Ubuntu)	New	Medium	Unassigned

Bug Description

Since the updates which fixed the dri problem on my ATi X600XT, the maximum
screen resolution i can obtain using fglrx is 1024x768@60Hz. Using the "radeon"
driver, I can obtain 1280x1024@60Hz, which is the maximum resolution for my
monitor (a Philips 107S) according to the specs.

Revision history for this message

sebastiaan (sebastiaan) wrote on 2005-09-20:

xorg log showing no strange errors... Edit (44.4 KiB, text/x-log)

Created an attachment (id=3938)
xorg log showing no strange errors...

Revision history for this message

sebastiaan (sebastiaan) wrote on 2005-09-20:

xorg.conf Edit (19.1 KiB, application/octet-stream)

Created an attachment (id=3939)
xorg.conf

Revision history for this message

Memo (memo-cj-ro) wrote on 2007-03-27:

xorg.conf.20070327140757 Edit (3.5 KiB, text/plain)

Original xorg.conf - resolution was ok 1024x768@85hz

Revision history for this message

Memo (memo-cj-ro) wrote on 2007-03-27:

xorg.conf Edit (3.5 KiB, text/plain)

xorg.conf after installing xorg-driver-fglrx

It can be easily seen that the monitor has not been properly detected, and maximum frequency was set at 60hz.

I restored the original file, modifing it as follows:
------------------------------
Section "Device"
Identifier "ATI Technologies Inc RV370 [Sapphire X550 Silent]"
Driver "ati"
BusID "PCI:1:0:0"
EndSection
------------------------------
changed to:
------------------------------
Section "Device"
Identifier "ATI Technologies Inc RV370 [Sapphire X550 Silent]"
Driver "fglrx"
BusID "PCI:1:0:0"
EndSection
------------------------------

Added the following block:
------------------------------
Section "Extensions"
Option "Composite" "0"
EndSection
------------------------------

Restarted X server and all went fine.

Revision history for this message

Bryce Harrington (bryce) wrote on 2007-04-27:

This looks like bug 3731. Note that between Memo's two xorg.conf files that the monitor got switched from

Section "Monitor"
Identifier "COMPAQ 7500"
Option "DPMS"
EndSection

Section "Monitor"
Identifier "Generic Monitor"
Option "DPMS"
HorizSync 28-51
VertRefresh 43-60
EndSection

which artificially constrains the sync and refresh rates X can use, which often results in failing to recognize otherwise good modes. You may also need to add "1280x1024" in the Modes lines. I suspect with these changes, you'll be able to use either driver.