No "Low Battery" warning on new (November 07) MacBook - Kernel Panic

My g/f's 2.16Ghz Macbook has SVM enabled and hers goes into Hibernate just fine. I'm going to turn off SVM tonight and see if there is any difference.

Thanks Psychonaut15!

That does seem to be very sound advice you are giving there. I just checked, and I too had hibernatemode set to 3, whilst the secure memory feature was on. I turned it off now (and restarted). I am very curious if this will get the desired results.

The only thing that surprised me was that this special mode for secure virtual memory was not mentioned in "man pmset". Nor that the hibernate mode changes between 3 and 7 when the secure virtual memory state gets changed.

If this fixes the problem I will surely file a bug about it with Apple. The guy at the Apple Service Centre yesterday (when I hadn't seen this solution yet) told me this was "expected" behavior amongst MacBooks.

It worked! Thank you so much Psychonaut15!!!

See my blogpost about this topic:
http://www.johankool.nl/2008/03/macbooks-hibernation-and-secure-virtual-memory

Hi,

I tried it but unfortunately it doesn't work for me.
It still "dies" at about 50%.

Hello,

As you wrote in your last message about Psychonaut15 solution, I was wondering myself about HOW DOES MACWORLD HINTS KNOW ABOUT the number 5 or 7 we have to put into hibernatemode even if it is not at all mentioned in man pages of pmset or in even a web pages of Apple support web site.

So, after an intensive search about this on the world wide web, I found a website who talks about these numbers 5 and 7 and whom seems to have the response to our quesitons AND it seems that MACWOLRD didn't understand what is it AT ALL!!!!

Check it out : http://db.tidbits.com/article/9115

In fact, there is NO BUG in Leopard, hibernatemode 5 & 7 meens that even if SecureVirtualMemory is checked, MacOSX doesn't encrypt the RAM image to disk. (comparing to mode 1 & 3 who let MacOSX encrypt RAM disk image if SVM is checked in Preference Panel).

So, it meens that it was normal that some people have hibernatemode 3 and SVM checked in Preference Panel.

Finally, it seems that forcing MacOSX to ignore encrypting image disk make our MacBook (me too for the first cycle since i changed to mode 7 ) sleep normaly instead of shutting down. And that it could be the same to uncheck the box in pref panel.

And if it solve lastingly the problem, it could meens that the problem comes from the SVM process before going to safesleep !

Thank you for your attention... and I am waiting for you comments.

Hello wapdgn,

Thanks for providing that link. It certainly helps to understand the problem even better.

So if you set bit 2 in pmset for hibernatemode, your memory will be saved to disk irregardless of wether you have enabled or disabled secure virtual memory. This of course could easily give you the false illusion of having secure virtual memory enabled, whereas it is not treated as such during safe sleep.

The TidBits article explains how bit 2 was a temporary workaround for problems with hibernation and secure virtual memory. It was subsequently removed when those were fixed. Clearly there still is some work left to be done with regards to safe sleep, secure virtual memory and the MacBook.

With this knowledge I have to conclude that the problem is not so much caused by a wrong setting for the hibernatemode as I expected before, but in the way secure virtual memory gets dealt with.

My advice for MacBook owners stays the same though: disable secure virtual memory. The drawback is obviously the risk of people snooping through your virtual memory, but in my opinion that does not outweigh the benefit of having ones work preserved when the battery goes empty.

I purposely did not explain how to change the hibernatemode in pmset (to 7 for example). Unchecking the secure virtual memory checkbox is in my eyes for now the best workaround for the sudden shutdown problem with MacBooks at this moment.

Ok everyone. Here is where I'm am now on this thing. I have contacted apple and they gave me advice and emails telling me to reset the System Management Controller (SMC). I followed their directions but it still acted the same.

Now, although we never spoke of it, they also (at the same time) emailed me another set of directions for resetting the PRAM and NVRAM. Before I did this I did run my computer down to verify that it still wasn't working correctly and as expected it shut down in the lame way we all hate. So I tried the resetting of the PRAM and NVRAM. The directions are:

1.Shut down.
2.Find the Command, Option, P, and R keys. You will need to hold all four down at the same time in step 4.
3.Turn on the computer.
4.Press and hold the four key mentioned. You must have them pressed and held before the grey screen appears.
5.Hold the keys down until the computer restarts and you hear the startup sound for the second time.
6.Release keys.

So I did this. Restarted again for the heck of it. Then let it run down. So far it has worked but I will be impressed if it works several times in a row.

By the way, I looked at my sys profile power info and the battery now reads as a maximum 49xx instead of 51 or 52xx. XX being digits that I don't remember.

If it works after several run downs I will let you all know that it was a success. If it doesn't continue to work I won't mention anything.

R

After a PRAM & SMC reset, with SVM off, the computer still shuts off at 0% instead of going to sleep or safesleep.

What doesn't explain it is my g/f's Macbook is running the exact same build of Leopard w/ all updates (10.5.2) w/ SVM turned on, and hers does not have this issue at all.

hello juan,

Did you try go swap tour battery with your girlfriend to see what happend?
It could be very interesting to know.

Thank you for your help!

Hi, it is interesting post. I followed the direction. But, it is not working for me.

claucojo wrote:
Hi,

I tried it but unfortunately it doesn't work for me.
It still "dies" at about 50%.

If your die at 50% it is not related to the "low battery" bug, but it's a defective battery

my two cents

Sorry to hear that Juan. I have just finished running down the battery three times and so far it is working normally. I hope I just didn't jinx myself. Please post the answer about switching batteries when you get a chance and good luck. I am hoping that I will no longer have to post anything assuming the computer stay in working order.

R

I reset SMC and PRAM, swapped batteries w/ my g/f's Macbook, and the issue did not happen. I tried it twice and the issue did not persist.

As far as I can tell, it appears to follow the battery.

In the System Profiler, the Firmware Ver. on her battery is: 102a
...on my battery, the Firmware Ver. is: 0110

Both batteries have the same mfg, hardware version, etc.