Public bug reported:
I have a Radeon 9000 Pro video card and LG Flatron L222WS wide screen
LCD monitor on Kubuntu Gutsy.
The native resolution of LCD is [EMAIL PROTECTED] Hz.
The problem is with modeline selection that's performed by X server.
There are two autodetected modelines that qualify for the native
1680x1050 resolution:
(II) RADEON(0): Modeline "1680x1050" 119.00 1680 1728 1760 1840 1050 1053
1059 1080 -hsync +vsync
(II) RADEON(0): Modeline "1680x1050" 146.25 1680 1784 1960 2240 1050 1053
1059 1089 +hsync -vsync
The first one doesn't work correctly - the montor only displays the
central part of the viewport, and the left and right side are cut off,
and using the "auto" button on the monitor doesn't help. The second
modeline is OK. But it's the first one that is chosen by X automatically
as the preferred one.
"xrandr --verbose" displays those modes this way:
BAD:
1680x1050 (0x47) 119.0MHz -HSync +VSync
h: width 1680 start 1728 end 1760 total 1840 skew 0 clock 64.7KHz
v: height 1050 start 1053 end 1059 total 1080 clock 59.9Hz
GOOD:
1680x1050 (0x48) 146.2MHz +HSync -VSync
h: width 1680 start 1784 end 1960 total 2240 skew 0 clock 65.3KHz
v: height 1050 start 1053 end 1059 total 1089 clock 60.0Hz
Notice that the bad mode has a vertical refresh of 59.9 Hz. However,
when I choose "60Hz" in display properties, this 59.9 Hz mode is used.
There's no way to switch to the 60.0 Hz mode using GUI (using
systemsetting and krandrtray).
However, using "xrandr --output VGA-0 --mode 0x48" I can switch to the
correct mode. I got the 0x48 mode identifier from "xrandr --verbose".
I can permanently force X to use this particular modeline by default by
placing the following entries into the "Monitor" section:
Modeline "1680x1050 at 60.0" 146.25 1680 1784 1960 2240 1050 1053 1059
1089 +hsync -vsync
Option "PreferredMode" "1680x1050 at 60.0"
However, X should automatically pick the 60.0 Hz mode over the 59.9 Hz
mode.
** Affects: xorg (Ubuntu)
Importance: Undecided
Status: New
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X selects wrong modeline for LG Flatron L222WS
https://bugs.launchpad.net/bugs/212018
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