Problem with video related system lockup

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Information about the problem of system lockups related to high video load.

Problem description

Occasionally, under high video load (e.g. scrolling text or moving windows), the computer becomes unresponsive or the computer becomes unresponsive during 3D rendering.

Affected Models

  • ThinkPad A22e
  • ThinkPad T20, T21, T22, T23
  • other ThinkPads with an S3 Savage video card

Affected Operating Systems

  • Any OS using the XFree86/Xorg 'savage' driver


The problem of lockups due to 2D video load is already known about/solved by the driver development team. According to the savage manual page, the problem is related to "a chip bug in the Savage graphics engine that causes a bus lock when reading from the engine status register under high load". Also according to the same source, "the bug affects about 4% of all Savage users."

The problem of lockups or video corruption as a result of 3D rendering is less well-known/understood. There appears to be a bug in AGP on Thinkpads interacting with Savage graphics cards. For reference, there was a recent discussion of this problem on the Linux-Thinkpad Mailing List.


If lockups are occuring under 2D video load (moving windows, scrolling), or you are using XFree86 or an XOrg version older than 6.8.x, add the following line to the Device section of your XF86Config-4/xorg.conf file:

Option     "ShadowStatus"

If you are experiencing lockups related to 3D rendering (using DRI) and you are using an XOrg version more recent than 6.9/7.0, you may need to add one or both of the following lines to the Devices section of your xorg.conf file:

Option     "BusType" "PCI"
Option     "DmaMode" "None"

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