Bug#488277: I have exactly the same problem

Alex Deucher alexdeucher at gmail.com
Tue Jul 1 10:52:00 PDT 2008

On Tue, Jul 1, 2008 at 11:26 AM, Eric Valette <Eric.Valette at free.fr> wrote:
> Alex Deucher wrote:
>> On Tue, Jul 1, 2008 at 3:56 AM, Eric Valette <eric.valette at free.fr> wrote:
>>> Alex, Julien
>>> First thanks for your help.
>>>> The modes in your screen section apply to all outputs.  The ones in
>>>> your monitor sections only apply to the specific monitor in question.
>>> I removed the mode lines from the screen sections. I did not add them back
>>> to the monitor section as they are correctly probed by the driver.
>>> Result is no change. The display on the external lcd is only a portion of
>>> the whole 1400x1050 resolution. Explicitly setting the resolution of the
>>> LCD, does not change anything. I still have to resort to the script docked
>>> to have a correct display.
>>> If you have any other suggestion, please tell me I will give it a try.
>>> NB: I would prefer to have a single configuration file for both config.
>>> Using xrandr or a script like today is ok. With kde4, krandrtray will enable
>>> to to this graphically.
>> you'll need to specify a preferred mode per-output if you don't want
>> to use the default preferred modes for each monitor:
>> http://wiki.debian.org/XStrikeForce/HowToRandR12
>> Alex
> xrandr --auto
> xrandr -q
> Screen 0: minimum 320 x 200, current 1400 x 1050, maximum 1600 x 1200
> VGA-0 connected 1280x1024+0+0 (normal left inverted right x axis y axis)
> 338mm x 270mm
>   1280x1024      60.0*+   75.0     59.9     60.0*
>   1600x1024      60.0
>   1400x1050      60.0
>   1440x900       60.2
>   1280x960       60.0     59.9
>   1280x800       60.0
>   1152x864       75.0     74.8     69.8
>   1280x768       60.0
>   1024x768       75.1     75.0     70.1     60.0
>   832x624        74.6
>   800x600        72.2     75.0     60.3     56.2
>   640x480        75.0     72.8     72.8     75.0     66.7     60.0     59.9
>   720x400        70.1
> DVI-0 disconnected (normal left inverted right x axis y axis)x 1024)
> LVDS connected 1400x1050+0+0 (normal left inverted right x axis y axis)
> 0mm x 0mm
>   1400x1050      60.0*+
>   1280x800       60.0
>   1280x768       60.0
>   1024x768       60.0
>   800x600        60.3
>   640x480        59.9
> S-video disconnected (normal left inverted right x axis y axis)
> If I now read the output of xrandr correctly, the preferred mode is
> correct for both monitor (maximum resolution of each monitor) just I do
> not want the number of pixel displayed on my LCD being a 1280x1024
> windows of a 1400x1050 output but because then I cannot seen the whole
> picture.

what modes do you want on each head?  the native modes of each head
are different. you can either have both heads at 1280x1024 or some
other resolution common to both heads or have them at different modes.

> Then if I put something like
> Option "PreferredMode" "1280x1024_60.00" on my LVDS panel, then I will have to use xrandr to swicth manually when undocking.

If you laptop produces acpi dock events, you can run an script with
xrandr when the event comes in.

> Side question: why are the xrandr displayed mode wrong ?(no 1600 x1024
> for the VGA-0, and 1280x1024 is possible on the LVDS). From memory it
> does not reflect what the drivers correctly found probing the displays
> (see my previous Xorg.0.log)

The laptop panel only one mode, it's native one: 1400x1050.  We add
the other smaller modes via the panel scaler to enable uses to use
non-native modes on their panels.  As for the VGA port, the xserver
adds the common server modes that fit into the sync ranges provided by
the edid ffrom your monitor.  I'd argue that we should only add the
modes in the edid, but CRT uses tend to like to use various other
strange modes.


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