Arch Linux

joel.obrecht

Member

Registered: 2010-02-18

Posts: 13

[SOLVED] xrandr and Samsung 2343NW screen @ 2048x1152 cvt & gtf errors

Trying to configure Xorg / nouveau for making my screen work full resolution, I followed the wiki :
Xrandr#Adding_undetected_resolutions

But cvt provided me with a bad result making my screen printing kind of a fuzzy white screen... I got the output of the modeline generated by the proprietary nvidia tool, which works.

To test without harming too much the screen / being blocked, this command line might be useful (it puts a safe mode after 5 seconds) :

$ xrandr --newmode "2048x1152_60.00-test" 156.750 2048 2096 2128 2208 1152 1155 1160 1185 +hsync -vsync && xrandr --addmode DVI-I-2 2048x1152_60.00-test && xrandr --output DVI-I-2 --mode 2048x1152_60.00-test && sleep 5 && xrandr --newmode "1024x768-safe" 65.00 1024 1048 1184 1344 768 771 777 806 -HSync -VSync && xrandr --addmode DVI-I-2 1024x768-safe && xrandr --output DVI-I-2 --mode 1024x768-safe

Nvidia modeline :

"2048x1152_60.00_rb" 156.750 2048 2096 2128 2208 1152 1155 1160 1185 +hsync -vsync

Works

CVT modeline :

[joel@jomain ~]$ cvt 2048 1152
# 2048x1152 59.90 Hz (CVT 2.36M9) hsync: 71.58 kHz; pclk: 197.00 MHz
Modeline "2048x1152_60.00"  197.00  2048 2184 2400 2752  1152 1155 1160 1195 -hsync +vsync

-> White screen

GTF modeline :

[joel@jomain ~]$ gtf 2048 1152 60
  # 2048x1152 @ 60.00 Hz (GTF) hsync: 71.52 kHz; pclk: 197.97 MHz
  Modeline "2048x1152_60.00"  197.97  2048 2184 2408 2768  1152 1153 1156 1192  -HSync +Vsync

-> White screen

So, what is wrong with those tools / command lines ?

As I didn't manage shortly some working xorg.conf or  working 20.nouveau.conf, I just added the following script in the mate session launch (in gnome system menu) :

$sudo  nano /etc/xrandrset

#! /bin/sh 
xrandr --newmode "2048x1152_60.00_rb" 156.750 2048 2096 2128 2208 1152 1155 1160 1185 +hsync -vsync
xrandr --addmode DVI-I-2 2048x1152_60.00_rb
xrandr --output DVI-I-2 --mode 2048x1152_60.00_rb

$sudo chmod 755 /etc/xrandrset

So when I connect to my session this script is executed and sets automatically the good resolution.

But in a perfect world I would like to have this resolution on KMS launch with nouveaufb, for GDM launch as well, as for my mate / gnome / ... session, directly in /etc/X11/xorg.d/ conf files...

Last edited by joel.obrecht (2012-07-16 10:12:03)

joel.obrecht

Member

Registered: 2010-02-18

Posts: 13

Re: [SOLVED] xrandr and Samsung 2343NW screen @ 2048x1152 cvt & gtf errors

I made some additions in the wiki as I think they may be of use.
Also,the following link may help :
Modeline Database

Last edited by joel.obrecht (2012-07-14 23:14:10)

joel.obrecht

Member

Registered: 2010-02-18

Posts: 13

Re: [SOLVED] xrandr and Samsung 2343NW screen @ 2048x1152 cvt & gtf errors

I succeded having gdmstarting with native resolution using this /home/user/.config/monitors.xml file :

<monitors version="1">
  <configuration>
      <clone>no</clone>
      <output name="DVI-I-1">
      </output>
      <output name="DVI-I-2">
          <vendor>???</vendor>
          <product>0x0000</product>
          <serial>0x00000000</serial>
          <width>2048</width>
          <height>1152</height>
          <rate>60</rate>
          <x>0</x>
          <y>0</y>
          <rotation>normal</rotation>
          <reflect_x>no</reflect_x>
          <reflect_y>no</reflect_y>
          <primary>yes</primary>
      </output>
  </configuration>
  <configuration>
      <clone>no</clone>
      <output name="DVI-I-1">
          <vendor>???</vendor>
          <product>0x0000</product>
          <serial>0x00000000</serial>
          <width>2048</width>
          <height>1152</height>
          <rate>60</rate>
          <x>0</x>
          <y>0</y>
          <rotation>normal</rotation>
          <reflect_x>no</reflect_x>
          <reflect_y>no</reflect_y>
          <primary>yes</primary>
      </output>
      <output name="DVI-I-2">
      </output>
      <output name="TV-1">
      </output>
  </configuration>
</monitors>

And copying it in /var/lib/gdm/.config/ :

sudo cp ~/.config/monitors.xml /var/lib/gdm/.config/

With this, gdm starts with native resolution and the xrandrset script is not needed anymore.

R00KIE

Forum Fellow

From: Between a computer and a chair

Registered: 2008-09-14

Posts: 4,734

Re: [SOLVED] xrandr and Samsung 2343NW screen @ 2048x1152 cvt & gtf errors

LCDs don't need as much blanking time as CRTs [1] so you can use 'cvt -r'. This will also yield the same result you get with the nvidia tool.

The tools are not wrong, they are just assuming/giving you one thing when you expect another.

[1] http://www.playtool.com/pages/dvicompat/dvi.html

---

R00KIE
Tm90aGluZyB0byBzZWUgaGVyZSwgbW92ZSBhbG9uZy4K

joel.obrecht

Member

Registered: 2010-02-18

Posts: 13

Re: [SOLVED] xrandr and Samsung 2343NW screen @ 2048x1152 cvt & gtf errors

Thank you, this new modeline works !
I make the update in the wiki + in post title.
Thanks

(I like very much archlinux wiki but for some new commands to me I tend to just copy/paste W/O fully understanding. Now I've learned something,thank you !)

Last edited by joel.obrecht (2012-07-16 10:08:45)