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[Bug 1322751] Re: Compiz running on Intel Haswell GPU has 100% CPU usage when computer is locked


Till devs do not find a real solution I made a BLOODY BRUTAL workaround which helps me.
PLEASE understand what my program is doing and decide if it is suits you or not.

I found "cpulimit" (can be installed from software center - at least in Ubuntu 15.10) which slows down a particular thread.
No, "nice" does not do the work, because "nice" just gives priorities and here we want that CPUs do not do "anything".

I wrote a small python script which
- checks if screen lock OR screensaver became active, if yes, it limits that thread with "cpulimit"
- checks if screen lock OR screensaver became inactive, if yes, ir removes all limitation

Again, it slows down compiz so violently as possible.
With my system the keyboard lock (Alt-Ctrl-L) fades out for 5-10 secs...
when I enter my password dots has 1 sec lag...

Screensaver part is added to eliminate this lock-screen delay.
Under "normal use" screensaver deactivates earlier, so compiz became much more responsive.

If your programs use compiz during screen lock, it is VERY LIKELY that
this script will slow down or somehow affect those programs as well, so
use it wisely!

For the script running you have to install python-dbus if you did not do it so far:
sudo apt-get install python-dbus

The python script itself:

#!/usr/bin/env python
import gobject
import dbus
import os
from dbus.mainloop.glib import DBusGMainLoop

def lock_and_screensaver_filter(bus, message):
  EventMember =message.get_member()
  if EventMember == "EventEmitted":
    args = message.get_args_list()
    if args[0] == "desktop-lock":
      os.system("cpulimit -b -P /usr/bin/compiz -l 1")
    elif args[0] == "desktop-unlock":
      os.system("pkill cpulimit")
  elif EventMember == "ActiveChanged":
    args = message.get_args_list()
    if args[0] == True:
      os.system("cpulimit -b -P /usr/bin/compiz -l 1")
      os.system("pkill cpulimit")

bus = dbus.SessionBus()
mainloop = gobject.MainLoop()

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  Compiz running on Intel Haswell GPU has 100% CPU usage when computer
  is locked

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