Red Hat Bugzilla – Bug 586581
Screen flicker when using Thinkpad T500 integrated graphics
Last modified: 2010-06-03 17:03:10 EDT
Created attachment 409600 [details]
Description of problem:
When "integrated graphics" is selected in the T500 BIOS, the graphics
screen (starting with the red boot screen and continuing with the window
manager after login) has a very distinct flicker. It is not regular like
you would associate with a refresh rate; it is random and quite obvious.
If instead one selects "discrete graphics" mode in the BIOS and reboots,
there is no flicker effect. (Unfortunately, discrete graphics mode is also
more power hungry.)
Please let me know if there are additional diags that you require (dmesg
Version-Release number of selected component (if applicable): RHEL 6.0 Beta
How reproducible: Continuous.
Steps to Reproduce:
1. Set graphics mode to "integrated" in BIOS
Thinkpad T500 model 2081-CTO with 15.4" WSXGA+ TFT (1680x1050)
Integrated graphics: Intel Graphics Media Accelerator (GMA) 4500MHD
Discrete graphics: ATI Mobility Radeon 3650 w/ 256MB
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux major release. Product Management has requested further
review of this request by Red Hat Engineering, for potential inclusion in a Red
Hat Enterprise Linux Major release. This request is not yet committed for
Does the issue go away if you add i915.powersave=0 to the kernel command line?
Thank you for helping as making RHEL better
The flickering does indeed go away if i915.powersave=0 is added to the kernel command line (via grub.conf).
I also determined that (without this parameter) the amount of flickering is proportional to mouse movements. Perhaps interrupt related?
Googling i915.powersave shows that this may be a duplicate of
I suspect this is fixed by:
Author: David John <email@example.com>
Date: Wed Jan 27 15:19:08 2010 +0530
drm/i915: Disable SR when more than one pipe is enabled
which is included in kernel -20 and later.
Please re-open if you can reproduce this on later kernels.