Comment 21 for bug 1561902

Thanks for the ideas! Did you mean 3.16.0-67 and not -87? I tried -67 now with and without vesafb:mtrr:0. System freezes within minutes in both cases.

I also tried mainline 3.16.7-ckt26-trusty and added vesafb:mtrr:3 to this and the system does NOT seem to freeze. This bug is weird. 3.16.0-38 was the first kernel with problems and mtrr was the only change that is not included in mainline. Why are mainline kernels working and normal not...? I want to believe that setting vesafb:mtrr:3 as boot parameter is exactly the same as setting mtrr = 3 in source code. (as said here https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1434581/comments/48)

No ctrl-alt-f1 or alt-ctrl-sysrq is possible when the system has frozen. Nothing works. Not even the WiFi LED from the hardware switch. I started a "find *.* /" after 3.16.0-67 boot and noticed that all disc activity stopped when system freezes. That probably tells that this is not just keyboard/mouse/graphics issue?