Some updated information from downstream:
- The kernel parameter acpi=off stops the freezes. I don't know exactly what is turned off with this. At least it turns off KMS, so kalessin had to revert to the karmic -intel driver whick has UMS support to test this.
- The kernel parameter nomodeset still produces freezes, so the fact that it stops with acpi=off is not due to using UMS instead of KMS.
Some updated information from downstream:
- The kernel parameter acpi=off stops the freezes. I don't know exactly what is turned off with this. At least it turns off KMS, so kalessin had to revert to the karmic -intel driver whick has UMS support to test this.
- The kernel parameter nomodeset still produces freezes, so the fact that it stops with acpi=off is not due to using UMS instead of KMS.
We have several 855GM freeze bug reports in Launchpad (https:/ /bugs.launchpad .net/ubuntu/ +source/ xserver- xorg-video- intel/+ bugs?field. tag=855gm% 20freeze& field.tags_ combinator= ALL) and many af them have batchbuffer dumps attached. A few of them have also been reported here already.