Q: NVDA(OpenGL): Channel exception!

One more anecdotal bit of evidence for the pile:

I've encountered this issue on an iMac6,1 with an NVIDIA GeForce 7600 GT.

Just upgraded to Adobe CS4 last week. Photoshop will hang the system every time I try to resize a selection. The following appear hundreds of times in my system.log, and I must power down manually to recover.

Sep 15 01:39:18 Macintosh kernel[0]: NVDA(OpenGL): Channel exception! status = 0xffff info32 = 0x3 = Fifo: Unknown Method Error
Sep 15 01:39:18 Macintosh kernel[0]: 0000000b
Sep 15 01:39:18 Macintosh kernel[0]: NVDA(OpenGL): Channel exception! status = 0xffff info32 = 0x6 = Fifo: Parse Error
Sep 15 01:39:18 Macintosh kernel[0]: 0000000b

Disabling OpenGL drawing in Photoshop's prefs solves the problem.

I have the exact same result.
This is not a hardware problem but a problem with the Nvidia video card driver.

The problem might be fix in 10.6 since my computer hasn't freeze yet. (Although this is maybe a bit too early to say).

That is certainly very interesting. Especially since I've had the issue since before 10.5.6.

dtwist wrote:
Disabling OpenGL drawing in Photoshop's prefs solves the problem.

Yes, the problem is certainly OpenGL-related (as the error indicates). The more areas you can disable OpenGL, the less you'll have the problem overall.

Just updated to 10.6.1

- I could not use PS CS4 with OpenGL on with 10.5.8, only with Open GL off: seems to be fixed in 10.6.1

- Still getting errors in Call Of Duty 2, however, error message changed to: +NVDA(OpenGL): Channel exception! exception type = 0xd = GR: SW Notify Error+ and a simple quit command stops the loop (with 10.5.8 had to reboot remotely or with the power button)

Conclusion: it's better than before, but not fixed entirely.

b

Please read this post to distinguish between the 2 problems:
http://discussions.apple.com/message.jspa?messageID=10124420#10124420

Winfer wrote:
Please read this post to distinguish between the 2 problems:
http://discussions.apple.com/message.jspa?messageID=10124420#10124420

If I readthis it looks to me you have had both problem and only the hardware issue has gome and the NVDA error still exist. Right?

I have had system freezes with my 7300GT's and Snow Leopard. The NVDA(OpenGL) Channel Exception and Timeouts are the cause of the freeze. I first noticed it in 10.6 with Path Finder and Photoshop. Turning off the OpenGL preference in PS helps but does not fix the problem. I have a thread going on Cocoatech's forums (Path Finder) because it always hangs when switching to PF. The folks at Cocoatech have been trying to track down this issue and they have been really helpful about posting what is going on in their research. They have supplied info to Apple and NVIDIA and yesterday, Cocoatech posted that NVIDIA has confirmed a problem with the drivers and they are working on a fix. Thought I would share this info with all of you and hopefully, this problem goes away with all of the NVIDIA drivers.

D.

I'm completely amazed at the lack of ANYTHING ON APPLE'S PART IN REGARDS TO THIS FIX!!!! I'm not even using PF or PhotoShop, I get this f@#king error every few minutes just browsing the internet, or reading a PDF. This is 100% unacceptable for Apple not to do something about this. I'm regretting putting away my PC right now, at least with it, I could "downgrade" the drivers, C'MON APPLE GIVE US A F@#KING FIX ALREADY YOU LAZY F@#KING A@#HOLES!!!

I'm with you. This is a serious issue that demands action.

Action required. No doubt.

Hi there!

I came across this discussion after I experienced those issues you all suffer from, coming and striking out of the blue, too.

With me it is pretty clear, at least at the moment, that reverting back to the Nvidia drivers from the 10.5.6 update did infact solve the "Channel exception" errors; as a matter of fact, they are all gone for me right now. Graphics is rock solid - I had the problems mainly with two applications, EyeTV and Handbrake, strange enough not with Photoshop CS4 (with OpenGL acceleration activated).

What I did: I used the software "Pacifist" to install all related KEXT files from the update. Using Pacifist you open the according "MacOSXUpd10.5.6.pkg" file and go to the Folder "System/Library/Extensions". There you mark all Geforce*.kext and NV*.kext files and then choose the "Install" Option from the menu (if you are on Intel Mac, avoid anything labelled PPC; for PowerPC users, only use the according PPC KEXT and ignore the other one).

Now you need to repair permissions and redo the extension cache. It´s most easy to use "KextHelper" for this. After you´ve ticked those routines, restart your Mac and everything should be fine.

To avoid a nonbootable system, for whatever reason, try to have a bootable backup of your system drive handy (firewire or USB based), just in case (if you haven´t got it yet, now is the time).

Needed/used software:

- Mac OSX Update 10.5.6: http://support.apple.com/kb/DL752
- Pacifist Package Installer: http://www.charlessoft.com/
- KextHelper: http://cheetha.net/

I hope others have success with this, too. At the moment I am pretty confident that you just need to revert back the drivers to 10.5.6 status and NOT a complete reinstallation of OSX itself.

I use a Nvidia 7300gt under OSX 10.5.8.

Faddh,

I tried your method without success. I did not get a kernel panic but the machine would not boot correctly. It either got stuck on the white apple loading screen or got stuck on the blue screen afterwards.

Message was edited by: hachaboob

Message was edited by: hachaboob

I am sorry to hear this. The reasons very likely are wrong permission settings for the newly installed kext files. This happened to me, too. It´s nothing severe, but annoying to fix if you haven´t got a bootable backup system in place. Your system definitely is not trashed in any way, just a bit confused, so to speak. But before you proceed, check whether by accident you have installed kext files which don´t suit your system (PPC ones if you are on Intel or vice versa).

What you can do then is: Boot your second system, start the OSX unix shell called "Terminal" (to be found at /Applications/Utilities) and enter the following commands at the prompt/blinking cursor (RETURN is a keyboard stroke; xxx is the name of the affected volume; you are called to enter your administrator password after the first command):

sudo chmod -R 755 /Volumes/xxx/System/Library/Extensions/ RETURN
sudo chown -R root:wheel /Volumes/xxx/System/Library/Extensions/ RETURN
sudo touch /Volumes/xxx/System/Library/Extensions RETURN
sudo touch /Volumes/xxx/System/Library/Extensions RETURN

After this, restart and see, if it helped.

If you don´t have a second bootable system available, restart your Mac and keep the "s" on the keyboard pressed until white text on black background appears. You now boot into the so called "single user mode", which essentially is OSX without eye candy, the pure UNIX based "terminal" at your hand, and proceed as described above (print out this post in that case, for ease of use).

Hi,

Thank you so much for this tip. I was really exited to try it. The installation went fine. But now both of the software that I had problem with, won't open. (3DEqualizer and Autodesk Maya)

Do you think it could be a permission problem or something ?

Thanks,

JF