Tag Archives: t430

Jumpy KDE on a new T430

The KDE screen kept hanging every few seconds , and it drove me crazy, 
another error I've been seeing is in the messages log:


Jul  5 12:34:05 desktop kernel: [ 5807.441851] [drm:i915_hangcheck_ring_idle] *ERROR* Hangcheck timer elapsed… blt ring idle [waiting on 1688990, at 1688990], missed IRQ?
which kept repeating all the time.
I found a working solution at: 
the solution that worked for me is:

On Kernel 2.8.38: /sys/module/i915/parameters/semaphores is set to 0
On Kernel 2.8.39: /sys/module/i915/parameters/semaphores is set to 1

if i do the following:

sudo -i
echo 1 > /sys/module/i915/parameters/semaphores

The Bug is also gone on 2.8.38 …..

If i set semaphores on 2.8.39 to 0 as it is default on 2.8.38, the bug also appears.


also there is a comment there talkeing about setting it up in boot through grub (I didnt test this yet though):


you can put this option in /etc/default/grub to make the change permanent
replace following line:


GRUB_CMDLINE_LINUX_DEFAULT="quiet splash i915.semaphores=1"


now my KDE runs just fine :)


fix for the autoboot suggestion:

it didnt work, a working solution was to edit the /boot/grub/menu.lst file and add i915.semaphores=1  to the end of the kernel line.

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