Re: [Ltsp-discuss] DVI graphics problem

[jam <ja...@ti...>]

On Friday 23 January 2009 05:30:32 lts...@li... 
wrote:
> I have set up a Kubuntu 8.04 LTSP server as a virtual machine at a VMware
> Server 2.0. The underlying operating system is an Ubuntu server 8.04.
>
> I have installed the ltsp-server package not the ltsp-server-standalone and
> I am redirecting the clients from the base server's dhcp server to the
> virtual ltsp server.
>
> Our clients are HP T5735 ThinClients with Dell 2209W TFT Monitors. I can
> use DVI and VGA ports to connect the devices.
>
> If I use the VGA interface the resolution is automatically set to 1680x1050
> but the display is flickering (and you probably get a headache after 10 min
> looking at it).

LCD displays don't flicker, they don't work like CRTs that scan 1 line at a 
time. There IS a problem, just not sure what it is. It is NOT vertical refresh 
rate.

> If I use the DVI port the resolution is stuck at 1280x768 but the display
> is crystal clear. When trying to change the resolution in the kcontrol
> module, kde tells me it is not installed (using the vga port the module is
> there and I can change the resolution as i like).

kcontrol CAN'T work !!! You are running on the SERVER but displaying on 
another machine (the client)

The xserver ASKs the display what it wants and then uses that. Why is it 
getting the wrong answer.

> Further I have tried to edit /var/lib/tftpboot/ltsp/i386/lts.conf like
> this: [default]
>     X_COLOR_DEPTH=24
>     LOCALDEV=True
>     SOUND=True
>     NBD_SWAP=True
>     SYSLOG_HOST=pluto
>     XKBLAYOUT=de
>     XSERVER=vesa
> #  XSERVER=vmware
> #    XSERVER=radeon
> #    XSERVER=ati
>     X_MODE_0=1680x1050
> #    X_MODE_0="1680x1050@60i" 66.01 1680 1712 1960 1992 1050 1074 1079 1103
> interlace
> #    X_VIDEORAM=16384
> #    XF86CONFIG_FILE = /etc/X11/xorg.conf

Um did you READ what you may say. According to my 
/opt/ltsp/i386/usr/share/doc/ltsp-client-core/examples/lts-parameters.txt.gz

X_MODE is NOT an option so doing nothing IS expected

> Xrandr gives me this output on a ThinClient when setting XSERVER to ati,
> radeon:
> Screen 0: minimum 320 x 200, current 1280 x 768, maximum 1920 x 1200 VGA-0
> disconnected
> 1280x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm DVI-0
> disconnected (normal left inverted right x axis y axis)
> 1280x768 (0x52) 80.1MHz
>        h: width 1280 start 1344 end 1480 total 1680 skew 0 clock
> 47.7KHz
>        v: height 768 start 769 end 772 total 795 clock 60.0Hz
>
> and with XSERVER=vesa:
> Screen 0: minimum 640 x 400, current 1280 x 1024, maximum 1280 x 1024
> default connected 1280x1024+0+0 0mm x 0mm
>    1280x1024      76.0*
>    1152x864       76.0
>    1024x768       76.0
>    800x600        73.0
>    640x480        73.0
>    720x400        71.0
>
> I do not care if I use the DVI or VGA interface but i want the proper
> solution AND a non flickering display.

When the display flickers what does the monitor info say?

I think your problem is not detecting the correct display driver. vesa won't 
do 1680x1050 but the other driver flickers, and dectection is mot done on DVI 
hence vesa and wrong for VGA hence flicker.

James