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Stopping Screen Flickering on Ivy Bridge Laptops using Linux

1349486496-xrandr

There is nothing worse than getting your hands on a new ultra thin ultrabook, putting your favorite Linux based OS on it to find that for whatever reason the screen tears like a knife through toilet paper.. Fear not, there may be an answer..

This all started about a month ago with a new Acer Aspire S3 and I blogged my woes getting Ubuntu working on it on here http://blog.projectz.me/2013/06/15/getting-ubuntu-working-on-the-acer-aspire-s3/ however as the blog suggests i did find a resolution in XrandR however there was a snag, it only worked in Ubuntu. so when I switched distros to Opensuse the fix didn’t work..

In Ubuntu when you type in

xrandr

you get back two screen resolutions which are similar, 1366×768 and 1360 x 768 so typing in

xrandr -s 1360x768 -r 60

sets the screen to a refresh rate and a resolution it works well with..

However when you install OpenSuse or Sabayon (as examples of two I have and I see the same issue) when you type xrandr there is no 1360×768 option and its not possible to set the refresh rate on the 1366×768 option to anything lower than 60+ (which in my installs was 75)

There isn’t much useful support out there for screen tearing over the “change the xorg.conf” which is pointless because OpenSuse 12.3 doesn’t use it in the same way..

However, as with all problems, there is direction in the furthest reaches of the internet and I found some helpful guidence on xrandr and put this together..

as root

nano /usr/local/bin/setreslow

and the script looks like this

xrandr --newmode "1360x768_60.00"  84.72  1360 1424 1568 1776  768 769 772 795  -HSync +Vsync
xrandr --addmode LVDS1 1360x768_60.00
xrandr -s 1360x768_60.00 -r 60

I will try and explain how I got this

the first line has a set of resolutions which were obtained from the command

gtf 1360 768 60

with the numbers being the desired resolution and the command outputs as follows

# 1360x768 @ 60.00 Hz (GTF) hsync: 47.70 kHz; pclk: 84.72 MHz 
Modeline "1360x768_60.00"  84.72  1360 1424 1568 1776  768 769 772 795  -HSync +Vsync

 

 

The second line is adding the new display, i used LVDS1 because that is what the screen is described as in the KDE Display Section

the last command sets the screen to the new resolution, however you might want to run xrandr as a command on its own first to check it works.

This is only fixing the new screen setup per session, so if you reboot, it needs to be run again, which is why i put it in /usr/local/bin as its in the path, i also have it running when KDE starts (or Gnome) and that works quite well, a flickering login screen i can deal with..

I hope this helps someone else..

 

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One comment on “Stopping Screen Flickering on Ivy Bridge Laptops using Linux

  1. Pingback: Links 8/7/2013: A Lot of Linux (Kernel) News | Techrights

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