[How to] Solve problem with Intel graphics caused by high CPU usage of Kslowd / Kworker – Linux kernel 2.35 – 3.8

EDIT on 05/11/2013: On Kernel 3.8.x you may have to add echo N> /sys/module/drm_kms_helper/parameters/poll to /etc/rc.local (before exit 0) to fix the issue.

EDIT on 05/21/2013: On Kernel 3.8.x – 3.9-rc5 a regression causes an irq storm from the i915 and the drm polling parameter is somehow ignored, and the suggested fix won’t work anymore. If you are experiencing the issue:

1) Downgrade to a different kernel, preferably 3.2.x

2) Add echo N> /sys/module/drm_kms_helper/parameters/poll to /etc/rc.local (before exit 0) OR add drm_kms_helper.poll=0 to grub boot parameters, to bring your system back to sanity.

This is just a workaround, track the issue here: https://patchwork.kernel.org/patch/2400621/

–Original post–

Some minor issues with the Linux kernel release starting from version 2.35 causes the X-Server on the system to perform miserably. I started experiencing the problem ever since I upgraded to kernel 2.35. It became almost impossible to use by laptop so I’m summing all the information I gathered from various Bug reports.

And yeah, the solution to it of course 🙂

Affects: Lots of computers with the Intel Graphics Accelerator

Issues:

• Kernel 2.35* : Mouse freezes intermittently some time after boot up. Keyboard activity is good. This results in an almost unusable desktop environment. Top will report the high CPU usage by 3-4 processes named – kslowd000, kslowd001, kslowd002 …
• Kernel 2.36* and beyond : Mouse freezes some time after boot up. This is more like a permanent freeze and system activity is impossible. Only solution is to reboot but it’s just a matter of a moment that the problem will come back.

Fix:

1. Type ‘uname -a’ to the shell to find out the version of kernel you are using. uname will return something like:

    Linux souri.razr 2.6.36.1-11.fc15.i686 #1 SMP Fri Dec 3 12:38:48 UTC 2010 i686 i686 i386 GNU/Linux

2. Here 2.6.36.1.-11 shows which version of kernel I’m using right now.
3. For those of you using some kernel that has version 2.36.* proceed to step 5.
4. For those of you using kernel 2.35.* , a kernel upgrade is required. Nothing to be scared of! Just need to type in:
   
#yum update kernel [in Fedora] OR #apt-get upgrade #apt-get install kernel [in Ubuntu]
5. This should update your kernel to the latest version that your distribution provides. Uname should now report a kernel version >=2.36.The update to kernel >=2.36 is essential because it enable a feature to disable the DRM_KMS_POLLING feature of the kernel. It is bot possible to disable DRM_KMS_POLLING for the 2.5 kernel. Maybe in some future bug-fix release of the 2.35 kernel they are going to patch this.
6. Reboot your system with the new kernel.
7. Open shell and become root.
8. Type #echo N> /sys/module/drm_kms_helper/parameters/poll This should drastically reduce the system load and put your system back to normal.
9. Note that this will only be sustained till system reboot. After reboot the value will revert back to poll=Y
10. For a sustained effect:  #echo "options drm_kms_helper poll=N">/etc/modprobe.d/local.conf

Hope this will help your woes. Enjoy! Please post any problems you may experience.

Also, kindly post the output of your uname -a, in case this helped you.

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