Comment 6 for bug 1503541

This bug also affects me. Well, now it doesn't anymore, because I've downgraded my system kernel.

Device: notebook Dell Inspiron 5548

Operating system: 64-bit XUbuntu Linux 14.04

Processor: Intel Core i7-5500U

Video: dual chip. These are the two display controllers:
- Advanced Micro Devices, Inc. [AMD/ATI] Topaz XT [Radeon R7 M260] display controller 33000000Hz (requires kernel module / device driver "fglrx"); and
- Intel Corporation Broadwell-U Integrated Graphics VGA compatible controller 33000000Hz (requires kernel module / device driver "i915").

Problem: the message "[drm:gen8_irq_handler [i915_bpo]] *ERROR* The master control interrupt lied (SDE)!" floods my dmesg. If I "cat /var/log/kern.log |grep -i i915" i see a huge amount of messages exactly like this one, hence I can only assume that the kernel module i915_bpo is buggy. Also, my notebook was subtly powering off from time to time (unrelated with overheat, I'm pretty sure 'coz I've already monitored temperature parameters and also 'coz I'm using a cooling laptop base/pad).

Kernels I've tested which have this issue:
- 3.19.0-18-generic
- 3.19.0-23-generic
- 3.19.0-28-generic
- 3.19.0-33-generic
- 4.2.0-18-generic

All of them have the same problem: the kernel module "i915.ko" (in 4.2.0-18-generic) and the kernel module "i915_bpo.ko" (in kernels 3.19.0-??-generic) cause subtle system shutdown (halt / poweroff) in my notebook.

Solution: I downgraded to kernel 3.13.0-36-generic, which isn't buggy with its "i915_bdw.ko" (version 3.0) kernel object (module). Full path for this module: /lib/modules/3.13.0-36-generic/kernel/ubuntu/i915/i915_bdw.ko

Notes:
- "bdw" stands for "Broadwell"
- "bpo", I believe, stands for "backport"

IMO, this bug is pretty serious and is taking a lot of time to get fixed: my notebook could get damaged if it kept subtly powering off on an everyday basis like it was doing because of this bug. Hence, my strong suggestion to those who are experiencing this issue is to downgrade to a stable kernel version (I recommend kernel 3.13.0-36-generic.

If you don't want to downgrade your kernel: become root ('sudo su'), then open '/etc/default/grub' for edition (e.g.: 'gedit /etc/default/grub'), then add the 'nomodeset' option to "GRUB_CMDLINE_LINUX_DEFAULT=" (e.g.: GRUB_CMDLINE_LINUX_DEFAULT="nomodeset"), then save the file, exit the text editor and, still as root, run the command 'update-grub && telinit 6'. Your GRUB will be updated and your system will be restarted. After that you won't be able to see OpenGL graphics anymore (e.g. Xscreensaver openGL screensavers won't load), but your system will stop subtly powering off.