[Solved!?] GSOD after upgrading ram to 6GB - JMicron controller issue.

[SpokeDigital]

Solution found!

 

See my most recent post for the solution that seems to work for me. Additional items that could be tested: try older JMicron kexts to see if they can be fixed in the same way; test this solution under different OSX versions.

 

 

Hi there,

 

I'm not new here, but I somehow lost track of my previous log on. Anyhow, on with my question...

 

I need a bit of help to troubleshoot the cause of frequent Grey Screens of Death. I am assuming it is a kernel panic. I found some info to look at the "panic.log" file, but I do not seem to have this file -- searched for it, look in library, etc. It's just not there. What are the steps to troubleshooting this?

 

The issues started after I installed an additional 4GB of ram - 2X2GB PC6400 sticks. My other two sticks are the same manufacturer (Patriot), specs, etc. I have stress tested my system (12+ hours) under windows with Prime95 and run Memtest86+ (12+ hours) with no errors. I can't see how it is a ram problem, but the behavior of OS X seems to point to that.

 

Any ideas?

 

Oh, and I should add that I was running 10.5.2 for about 6 months with no significant errors before now.

[Beerkex'd]

My guess is one or more kernel extensions that are loaded on your system is not compatible with +2GB RAM.

 

Find out which of your kexts (or plugins inside kexts ending with Family) are older, patched versions.

 

There are probably more but the ones I know of are kexts for drive controllers.

These are patched to work with +2GB RAM:

http://code.google.com/p/darwin-ata/downloads/list

 

So if you're using any of those, try replacing them and see if it works then.

 

There's a bootflag that'll allow you to limit how much memory OSX can see, I think it's MAXMEM=2048 but you better look it up yourself because I probably got it wrong. Using this flag you'll be able to boot with all your RAM installed and replace the kext(s) you need to replace, and you won't have to worry that it'll crash while you do it.

 

Good luck.

[SpokeDigital]

Great pointers on where to start. I would have never guessed the kexts to be specific to ram size. I don't suppose there's an easy way to check the kexts to know if they are not compatible with +2GB RAM? If not, I guess I have some research to do.

 

I was thinking of just doing a re-install with iPC 10.5.6, and restoring files, user prefs, etc. through timemachine. Maybe that would be quicker and solve my issue. What do you think?

 

Thanks for your help so far.

[Beerkex'd]

It has something to do with 64-bit addressing. I dont' know the technical details.

 

Try replacing the drive controller drivers first. It's not that hard! Plus you'll learn things which is always good.

 

You can see what extensions are loaded on your system like this; click the apple, about this mac, more information, expand 'software' and click 'extensions'.

 

If any of the kexts that appear in the link I posted above are loaded, try replacing them with the patched ones.

Check and compare versions numbers and kext contents first.

 

If you decide to reinstall, IIRC the latest iPC DVD has the drive controller drivers fixed for +2 GB.

[SpokeDigital]

Find out which of your kexts (or plugins inside kexts ending with Family) are older, patched versions.

 

Okay, now comes the really noob question... where do I locate the kexts and how do I know if it's the one that needs patching?

 

Sorry for the really late follow up question. I had to put my computer back to a stable state, as there was work being done on the computer for which I could not risk a crash in the middle of it. Now I'm back to "playing" with my computer (as it should be :pirate2: ).

[SpokeDigital]

Never mind answering... I found out how.

 

For anyone else reading this looking to solve the same issue, you can get to your list of running kexts by opening terminal, type: kextstat

 

For me, it looks like maybe com.jmicron.JMicronATA (1.0.0) is the culprit. This makes sense as the GSOD seems to come when programs are trying to read/write to my IDE drive that is attached to the JMicron controller. I'm not getting crashes each time I use this drive, but seems to happen with sustained use (i.e. Transmission saving a file to that drive.)

 

Now to find a newer version.

[SpokeDigital]

There are probably more but the ones I know of are kexts for drive controllers.

These are patched to work with +2GB RAM:

http://code.google.com/p/darwin-ata/downloads/list

 

FYI -- the kext in the below link DO NOT work. I installed and got GSOD on boot. Luckily I could just go in and disable the jmicron controller and re-boot/restore and start over.

 

Of course it's quite likely I'm doing something wrong.

 

I think I'm just going to go back to try to update my install with iPC 10.5.6.

[Beerkex'd]

You can extract the JMicron kext from the iPC DVD with Pacifist. But I don't think it will help because the DVD has the same kexts that you can find here in the forum.

 

Actually it's a common misconception people have that installing another distribution is the only answer to their problems (yes I know that's not what you were going to do but what you said made me think of this).

There are probably a few exceptions (very few) but generally you can be sure that the patches and fixes that go on all the different OSX86 DVDs can be found and downloaded here in the forums.

 

btw I did tell you earlier on how you can see which kexts are loaded via the System Profiler.

Of course kextstat does the same thing plus it's more l33t since you are using the terminal.

 

I forgot something, If you have a setting in your BIOS called 'Memory Remap feature' or words to that effect, you should enable it. If you do have it, your motherboard manual should explain what it does and why you should enable it.

 

To really isolate the problem you can try keeping the JMicron controller disabled and see if OSX still crashes.

 

If it still crashes then you'll at least know that it isn't the JMicronATA.kext causing it.

[SpokeDigital]

Potential Solution found:

 

It appears that I have found a fix. The following seems to be working for me:

 

1) Extracted extracted latest iPC 10.5.6 Universal iso with Pacifist

2) Installed JMicronATA.kext with Kext Helper b7 (included with Kalyway 10.5.2 DVD)

3) Cross fingers and Reboot

3) Set JMicron controller to IDE mode in BIOS (pic attached)

a) FYI: AHCI mode resulted in GSOD on boot.

Solution Testing:

Previous crashes occured with sustained use of my IDE drive connected to the JMicron controller. In particular I was getting consistent panic when using Transmission to download files to this drive. Panic would occur within minutes of Transmission activity.

 

To test fix I did the following:

1) Ran Transmission saving data to the IDE drive -- no panic after 2 hours of steady use

2) Large file transfer between IDE and SATA drive. No panic after 3 copies of 2+GB file

 

Though my tests were not terribly conclusive, I am pretty certian this has fixed my issue. I will follow up with any futher panics.

 

My set-up:

Kalyway 10.5.2

Bios F13

6GB Ram - 2x1GB, 2X2GB

Main HD: WD 500GB SATA drive on ICH9 Sata port (also SATA DVD drive & Seagate 250GB drive on ICH9 ports)

Storage Drive: WD 500GB IDE (PATA) on JMicron IDE port

 

Additional system specs in my sig.

 

Special thanks to Beerkex'd for his help in pointing me in the right direction.