845G and 855GM freezes

This page is about the GPU hangs/freezes that occurs in Karmic on 845G and 855GM and possible resolutions for Lucid.

• Open bugs with tags 845g and freeze

• Open bugs with tags 855gm and freeze

Checklist for bug reports

• Does it happen on the login screen? gdm or kdm?
• Does it happen when desktop effects/compositing is turned off?
• Does it help to use the kernel option acpi=off?
• Does it help to use the kernel option nomodeset?

• Get batchbuffer dumps with xorg-edgers and xorg.conf option DebugFlushCaches

Links

• https://wiki.ubuntu.com/X/Troubleshooting/Freeze

• https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/447892/comments/23

Identifying the bad commit

It seems that upstream requires us to find out when the freezes started to happen. Jaunty may be a good platform for testing this.

• Does it work with Jaunty?
• Does it freeze if I install the 2.6.31 kernel in Jaunty?
• Do the freezes stop again if I then downgrade the intel driver to 2.4.x?

If the answer to all these questions are yes, there was a change in the intel driver after 2.4.x that made the freezes happen. The freezes weren't noticed until a change in the kernel between 2.6.30 and 2.6.31. Identifying these two changes would greatly help in resolving this bug.

To identify the driver change, run Jaunty with a 2.6.31 kernel where the freezes are present. Check the intel driver source code out from git. Use git-bisect and build different drivers and mark good and bad versions.

To identify the kernel change, run stock Jaunty and check out the kernel source code from git. Use git-bisect to identify good and bad versions.

How to install the 2.6.31 kernel in Jaunty

• Go to http://kernel.ubuntu.com/~kernel-ppa/mainline/ and into v2.6.31-rc3/ and download the file linux-image-2.6.31-020631rc3-generic_2.6.31-020631rc3_i386.deb (this is the first 2.6.31 kernel available for i386).

• Install the package with dpkg -i linux-image-2.6.31-020631rc3-generic_2.6.31-020631rc3_i386.deb

• Reboot. Test if it freezes.

• Verify that you run the right kernel with uname -a. Normally the newest kernel will be started by default. If you have other kernels installed (they install side-by-side), you may need to choose the right kernel from the Grub boot menu (Esc at boot to show the menu).

• Remove the kernel with dpkg -p linux-image-2.6.31-020631rc3-generic_2.6.31-020631rc3_i386.deb

• You may also want to try the 2.6.30.10 kernel to verify that the freezes do not occur with this.

There is some more informaiton about the mainline builds at MainlineBuilds.

How to install a 2.4.x -intel driver in Jaunty

• See https://launchpad.net/~ubuntu-x-swat/+archive/x-retro?field.series_filter=jaunty

• The 2.4.1 and 2.6.3 drivers have several legacy acceleration methods available that are not there in newer drivers. To use the same method as in newer drivers, add the line

Option AccelMethod "UXA"

to the Device section of xorg.conf. The default in Jaunty is

Option AccelMethod "EXA"

845G reports

855GM reports