Unable to change the refresh rate to 60hz with xrandr

My monitor supports 1920×1080 @ 60hz (LG W2486L) and graphic card (GeForce 9400 GT) using Ubuntu 12.04.

When I type xrandr -q I get this:

xrandr -q
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 1920 x 1080, current 1920 x 1080, maximum 1920 x 1080
default connected 1920x1080+0+0 0mm x 0mm
1920x1080 50.0*
1920x1080_59.90 59.9
1920x1080_60.00 60.0 

Right now the refresh rate is on 50 and hurt my eyes real bad. So I'm trying to change it to 60hz:

xrandr --output default --mode 1920x1080_60.00
xrandr: Failed to get size of gamma for output default

What I can do? I tried

gtf 1920 1080 60.0
# 1920x1080 @ 60.00 Hz (GTF) hsync: 67.08 kHz; pclk: 172.80 MHz
Modeline "1920x1080_60.00" 172.80 1920 2040 2248 2576 1080 1081 1084 1118 -HSync +Vsync
xrandr --newmode "1920x1080_60.00" 172.51 1920 2040 2248 2576 1080 1081 1084 1118 -HSync +Vsync
xrandr: Failed to get size of gamma for output default
X Error of failed request: BadName (named color or font does not exist) Major opcode of failed request: 153 (RANDR) Minor opcode of failed request: 16 (RRCreateMode) Serial number of failed request: 19 Current serial number in output stream: 19
xrandr --output default --mode 1920x1080_60.00xrandr: Failed to get size of gamma for output default

Someone have the solution for this? I can't work on the PC like that, 50Hz is very low and can't look at the screen more than 5 mins.

Thank you!

1 Answer

Your xrandr -q output shows that you have 1920x1080_59.90 resolution available

You can use this to set the new resolution

xrandr --output default --mode 1920x1080_59.90 

Also, if you are creating newmode using

xrandr --newmode "1920x1080_59.90" 172.51 1920 2040 2248 2576 1080 1081 1084 1118 -HSync +Vsync

You also need to add this mode using

xrandr --addmode default 1920x1080_59.90

And then set the new resolution using

xrandr --output default --mode 1920x1080_59.90