Screen lines at 75 hz

[BicyclerBoy]

I think the native is 1152x864 but 75Hz refresh is greater than max pixel clk in EDID..

$xrandr --newmode "1152x864_60.00"   81.75  1152 1216 1336 1520  864 867 871 897 -hsync +vsync
$xrandr --addmode HDMI-0 "1152x864_60.00"
$xrandr --output HDMI-0 --mode "1152x864_60.00"
$xrandr --output HDMI-0 --scale 1x1
$xrandr --fbmm 475x267

[heli1]

trash unity no good for nothing stupid make it better cant find nothing eny more
worse then windows

[Flying Mandarine]

BicyclerBoy: Am I supposed to add your code at the end of the file, or in place of something else? And is it safe (meaning, is there a risk for my computer to break down if it's not a resolution that's supported)? I've never seen a choice for such resolution, even on Windows.

heli1: Actually, I would be quite satisfied with it were it not for this problem... I've had my share of problems over the year, but in recent years, Ubuntu seemed to work perfectly for me, with Unity. So if I can solve the problem without resorting to something other than Unity, I'd prefer that!

[BicyclerBoy]

Just enter those cmds in terminal or stick them in a text file/script & run it from terminal..

I don't believe you can damage any modern monitor (inc CRT).

The 75Hz rates of 1280x1024 & 1152x864 are excluded from "video mode pool" because the pixel clock is greater than max in EDID.
The 60Hz refresh makes more sense.
Alternatively it is possible to force the max pixel clock freq test to be ignored, I just don't know the ati/radeon keywords..

If you want to try 1280x768 60p:

$xrandr --newmode "1280x768R"   68.00  1280 1328 1360 1440  768 771 781 790 +hsync -vsync
or
$xrandr --newmode "1280x768_60.00"   79.50  1280 1344 1472 1664  768 771 781 798 -hsync +vsync

you have to craft the remaining cmds to use the "mode label".

The problem with Unity was forcing it on users with no obvious/easy way to get to gnome-fallback or similar.
There should have been a Canonical version of "cinnamon" desktop.

[Flying Mandarine]

Great! I think the problem is nearly solved.

I entered those commands (1152x864_60.00 just didn't work, resolution not supported):

xrandr --newmode "1280x768_60.00" 79.50 1280 1344 1472 1664 768 771 781 798 -hsync +vsync
xrandr --addmode HDMI-0 "1280x768_60.00"
xrandr --output HDMI-0 --mode "1280x768_60.00"

And it worked!

However, when I restart the computer, it goes back to the 1024x768 resolution, even after I deleted the command line in Startup Applications.

So I decided to put each one of those three lines of code into a different startup application (or is there a way to maybe put all three into one "application?"), but it doesn't seem to do anything: it still goes to 1024x768.

Would you have any idea of how to set those three marvelous lines of code so that I don't have to type them every time I start the computer?

[BicyclerBoy]

I would try placing them in /etc/rc.local
or into a script with the script (full path) invoked/run from /etc/rc.local

Your script needs a shebang (#!/bin/sh) & execute bit set..

It is possible to create/use /etc/X11/xorg.conf but the syntax is a little different & not as flexible.

Try the reduced VB 60Hz timing as well. Should work on any DFP.
FYI.
The timings were generated from:
$cvt -r 1280 768 60

[Flying Mandarine]

Hi BicyclerBoy,

I spent a few hours trying what you said, but I'm afraid much of what you wrote is way too technical for me. I don't know whether to add those lines before or after the "exit 0" of the rc.local, I don't understand what you mean by "Your script needs a shebang (#!/bin/sh) & execute bit set.." and I don't know how to "Try the reduced VB 60Hz timing as well."

If this is too much work to explain, please disregard: you've helped me so much already, and the screen display now works fine if I enter those three commands each time I start the computer. Trying to do that automatically is just a minor issue.

Thank you,

FlyingMandarine

[BicyclerBoy]

Put the cmds in the rc.local file just before "exit 0"..

The "exit 0" sets the exit value to 0 (no error) if the script completes/gets to end.

The reduced (vertical blank) timings are the default 60Hz video modes over HDMI/DVI.

This cmd generates reduced blanking timings:
$cvt -r 1280 768 60

just try the reduced video modeline in place of the other "1280x768_60.00".
You need to change all 3 commands..

[Flying Mandarine]

Hi BicyclerBoy, sorry for the late answer,

I put the commands in /etc/rc.local; it looks like this:

# By default this script does nothing.

xrandr --newmode "cvt -r 1280 768 60" 79.50 1280 1344 1472 1664 768 771 781 798 -hsync +vsync
xrandr --addmode HDMI-0 "cvt -r 1280 768 60"
xrandr --output HDMI-0 --mode "cvt -r 1280 768 60"

exit 0

But it still didn't do anything -- although writing them separately one after another in the Terminal works very well.

[BicyclerBoy]

I should try out cmds before suggesting them..

I guess the above failed because the rc.local file is run before the X server is loaded..

Short of using an xorg.conf file (to be avoided)...
a script in ~/.xinitrc/ (private to user; "~" means home path)

The suggested system wide Xinit script location seems to have vanished..