What's Chris been doing?

It’s been a while since I blogged about the sleep component. There’s been a lot of activity on that front lately, so here’s a roundup of the news.

• You can now wake a sleeping machine by pressing a key on the keyboard.
• In theory you can also wake a sleeping machine by clicking a mouse button. However RHEL6.0 / SL6.0 seems to have a kernel bug which makes this not work any more. As far as I can gather, the kernel bug was fixed ages ago but RHEL deliberately removes the fix when building its kernel. Hopefully this will all be better in 6.1.
• The component now detects running cron jobs. If it finds one, and that job isn’t in the cronignores list, it keeps the machine awake.
• There are new disable and enable methods. These disable sleep, and undo the disable method, respectively. The idea is that they can be run by a machine’s user, for example by typing om sleep disable.
• The component should work on 64 bit architectures too.
• A bug which broke the execution of extra commands at suspend and resume has been fixed.
• A new blacklist resource allows the selective disabling of sleep for particular hardware models.
• The sleep component’s LCFG Wiki page has been thoroughly tidied and brought up to date. Take a look at that page for an introduction to the component.
• Sleep mostly seems to work reliably on SL6. One or two models are currently presenting problems (the Dell Optiplex 755 in particular) but solutions have been identified and I expect those models to sleep successfully too soon. Certainly my test 755 sleeps like a baby. (It wakes in the middle of the night to perform important functions…)
• Edit: I forgot to mention that the lcfg-level resources have now been beefed up so that the component can now be run out of the box with lcfg level headers: no extra configuration should be necessary. (More configuration is possible of course – see the LCFG Wiki page for some config ideas.)

With all these developments out of the way it’s looking likely that we’ll soon be rolling out the sleep component onto all the staff and postgrad DICE Linux desktops in Informatics. In addition the introduction of the blacklist resource clears the way for the possible adoption of lcfg-sleep by other schools and units too. I’m looking forward to that challenge; it’ll be great to see more power-saving from the Linux desktops across the University.