Powerbook Sleep Problem Fix

Sunday, 16 November 2008 07:29

My Powerbook G4 15" 1.6Ghz notebook has been far off better than a workhorse to me. And I even named it R2D2 cuz it has been a reliable computing companion whenever and wherever I need some serious work to be done. But, a few months ago, I noticed that after coming back from sleep mode, it goes back to sleep again and never wakes and can't go back to wake again. Apparently, the only way to wake it up is to detached the battery pack from the unit, removed the power cord, press the power button for 5 secs then return both the battery and power cord back. This was frustrating cuz after the unit boots up, you have to set the clock again and re-enter your wifi passkey (if you have any). I've also noticed a sluggish performance too once it runs for several hours.

I searched about the issue and found out that it's the powebook's trackpad temperature sensor that is causing the problem. The sensor would erratically display an abnormal temperature reading of 100C after going back from sleep causing the system's Power Managment Unit (PMU) to think it will overheat if it doesn't shut down. Checking the system.log at /var/log directory, I got this:

Nov 15 18:55:43 R2D2 kernel[0]: System Wake

Nov 15 18:55:43 R2D2 kernel[0]: Wake event 0008
Nov 15 18:55:43 R2D2 kernel[0]: PowerManagement emergency overtemp signal.
Going to sleep!AirPort: Link Up on en1
Nov 15 18:55:43 R2D2 kernel[0]: PowerManagement emergency overtemp signal.

This has been a common issue to Powerbook 15-inchers and Apple repairs it for free. That if your unit is still under warranty. Unfortunately, mine is not.

So I did a little homework and find a fix that would disable the trackpad sensor and stop telling false temperature to the PMU. And the easiest solution I got is to move a couple of system extension files; IOI2CLM7x.kext and AppleLM7x.kext from the /System/Library/Extensions folder.

You can use Finder to accomplish this task:

Go to the folder MacHD/System/Library/Extensions in finder.
Make a directory on your desktop called kext.backup (or whatever you want to call it)
Drag the files IOI2CLM7x.kext and AppleLM7x.kext to this new folder, it will copy them here for backup
Erase those same files in the Extensions folder by dragging them to the trash. Also erase the two files in /System/Library called Extensions.kextcache and Extensions.mkext.
Then reboot and reset NVRAM and PMRAM.
Do the victory dance.

Whoala!! The trackpad sensor doesn't tell any temperature reading anymore and my Powerbook can already wake up from a deep sleep.

The best solution yet is to get Apple replace the defective trackpad sensor. Now, I can sleep with a smile.