Q: MacBook Pro screen blinks

So there's an app that does what Apple cannot, i.e. make graphics card switching on the fly work for late 2008 MacBook Pro models?

It's very bad news that the blinking persists on later MacBook Pros...

By the way, I'm not convinced that using the 9600M video processor eliminates "Mr. Blinky."

Thnx SuperSizelt, Noted Meant WorkAround, not resolved... thnx for the correction.

It has however put an end to the frustrating blink. Guess one could force the graphics mode to use the Intel based card when working off the battery. Do you experience any blinking issues when you have a graphics mode selected, or only when Dynamic Switching has been turned on?

Message was edited by: webnetix

Hey Odysseus,

Had an earlier version unibody, late 2008 model without any issues. I only started experiencing the issue with my i7.

The gfxCardStatus app does not sort out the blink when in Dynamic Switching mode, but rather when the switching mode has been switched off and only one of the cards are used. The blink occurs (on my system), when the system dynamically switches from the Higher grade card to the lower one. I simulated this by leaving Dynamic Switching on. gfxCardStatus would show that the intel card was being used. I would then load up a copy of VLC and notice the switch from the intel based card to the NVidia based one. On closing VLC the system would swop back to the intel card and the screen would blink.

This was also simulated by toggling the options as mentioned in my previous post.

My guess is that this is a somewhat different problem from that mentioned by the majority of posts here, which concern the late 2008 model MacBook Pro.

All good,

Perhaps another interesting note, would be interested to see your results.

I've tailed the /var/log/windowserver.log file on OS X 10.6.4. This shows some logs when the graphics modes are switched.

I have the following results:

Switching from Intel to NVIDIA:

Aug 18 20:55:06 [145] performsync_muxswitch: unexpected monitor list 1 (3)
Aug 18 20:55:06 [145] performsync_muxswitch; initial state
Aug 18 20:55:06 [145] Mon 0x4272902: (0.000000, 0.000000) [1440.000000 x 900.000000]; HW (0.000000, 0.000000) [1440.000000 x 900.000000]; Mirroring 0x0 Mode 0 Rotation 0 Unit 2 (0x5)
Aug 18 20:55:06 [145] Mon 0x4272900: (3488.000000, 0.000000) [1440.000000 x 900.000000]; HW (3488.000000, 0.000000) [1440.000000 x 900.000000]; Mirroring 0x4272902 Mode 2 Rotation 0 Unit 0 (0x5)
Aug 18 20:55:06 [145] Mon 0x5b81c5c3: (1440.000000, 0.000000) [1024.000000 x 768.000000]; HW (1440.000000, 0.000000) [1024.000000 x 768.000000]; Mirroring 0x0 Mode 2 Rotation 0 Unit 3 (0x8)
Aug 18 20:55:06 [145] kCGErrorFailure: MappedDisplay Driver: can't set device gamma (e00002c7)
Aug 18 20:55:06 [145] performsync_muxswitch: bad monitor list 2
Aug 18 20:55:06 [145] kCGErrorFailure: MappedDisplay Driver: can't set device gamma (e00002c7)
Aug 18 20:55:06 [145] kCGErrorFailure: MappedDisplay Driver: can't set device gamma (e00002c7)
Aug 18 20:55:07 [145] kCGErrorFailure: MappedDisplay Driver: can't set device gamma (e00002c7)

Switching from NVIDIA to Intel:

Aug 18 20:54:34 [145] performsync_muxswitch: unexpected monitor list 1 (3)
Aug 18 20:54:34 [145] performsync_muxswitch; initial state
Aug 18 20:54:34 [145] Mon 0x4272900: (0.000000, 0.000000) [1440.000000 x 900.000000]; HW (0.000000, 0.000000) [1440.000000 x 900.000000]; Mirroring 0x0 Mode 2 Rotation 0 Unit 0 (0x5)
Aug 18 20:54:34 [145] Mon 0x4272902: (3488.000000, 0.000000) [1440.000000 x 900.000000]; HW (3488.000000, 0.000000) [1440.000000 x 900.000000]; Mirroring 0x4272900 Mode 0 Rotation 0 Unit 2 (0x5)
Aug 18 20:54:34 [145] Mon 0x5b81c5c3: (1440.000000, 0.000000) [1024.000000 x 768.000000]; HW (1440.000000, 0.000000) [1024.000000 x 768.000000]; Mirroring 0x0 Mode 2 Rotation 0 Unit 3 (0x8)
*Aug 18 20:54:34 [145] CGXMuxSyncStarted: Did not see IOGraphics adornment on incoming unit*
Aug 18 20:54:34 [145] kCGErrorFailure: MappedDisplay Driver: can't set device gamma (e00002c7)
Aug 18 20:54:34 [145] performsync_muxswitch: bad monitor list 2
Aug 18 20:54:34 [145] kCGErrorFailure: MappedDisplay Driver: can't set device gamma (e00002c7)
Aug 18 20:54:34 [145] kCGErrorFailure: MappedDisplay Driver: can't set device gamma (e00002c7)
Aug 18 20:54:34 [145] kCGErrorFailure: MappedDisplay Driver: can't set device gamma (e00002c7)

The interesting item in this log is highlighted in bold as it's the only item not reflected in the Intel to NVIDIA switch.

Would be interested to see what your log produces.

After the recent Graphics software update from Apple it feels like the appearance of mr Blinky is less frequent. Anyone with simular experience?

The strange thing for me is that after applying the update, I think I've seen my external display blink (MBP in closed clamshell mode), whereas in the past, the blinking only occurred when I was using my MBP's internal display

Hans, since applying yesterday's graphics update, it seemed far less frequent to me, as well. In fact, after going nearly two hours without seeing a blink at all, even while stress-testing the GPU, I initially thought it was fixed!

1 day later, I'm not really sure whether or not it's improved.

Pretty amazing that it actually exist. Switching graphics on the fly without a reboot or a log out. Something this individual could create and the vast army of Apple OS engineers/programers cannot even attempt to do. LOL

Seems better to me as well after a day or so. Anyone else?

I thought it was gone but the blinking has returned for me after a day or so. I had also reset SMC and PRAM again as well as the graphics update.

My 2009 MacBook Pro display started flicking and after reading this thread I've learned that it could be software or hardware related. That isn't too helpful to know.

I also learned that people who could take their systems in for repair to some near-by Apple service center often had to do it several times and the problem wasn't always solved. Others mentioned key combinations and what-not to reset blah-blah in the software, but the fix was usually temporary. I hoped that it was a software issue, and a temporary fix isn't acceptible.

So, I erased the harddrive and re-installed everything. I'm no longer experiencing the problem. Wouldn't it be awesome if someone could pinpoint the exact software issue and provide a better fix than re-installing everything? What is interesting to me is that I've got ALL of the same software re-installed and ALL of the Apple updates and patches and the flicker has not returned.

Again, even though the symptoms may be the same, I wonder whether the causes are the same for the 2nd- and later-generation MacBook Pro unibody models as for late 2008 models. The late 2008 models use the nVidia 9400M chips that supposedly have the same problems with the lead "bumps" as their 8600M predecessors.

But just for reference, when you did your reinstall, you didn't carry over any preferences whatsoever? Everything was reinstalled from scratch?

Tell us how you did it. Did you reinstall the OS from SL disk or some backup disk like time machine? Did you reinstall all your apps back one by one?

My late 08 MacBook Pro has had the same issue since I purchased it. I have never been able to take it in, though, as it's my only computer (for work)...until now. I have been watching this topic for a while though, in hopes of figuring out what is happening. Note: I haven't had a chance to read all the responses here, so hopefully this is not a duplicate question. If it is, sorry.

My question: for the people that have taken their MacBook Pro in for repair, are they repairing these machines in house with the Genius techs? Here is why I ask...

I have had other Macs (iMac, PowerBook, MacBook, MacPro) taken into the store and all the work (diagnosis, stress tests, etc) is performed in the store. The genius always asks 100 questions, one of which being have I restored my machine, reinstalled OS X, etc...and then asks what I've loaded (3rd party) onto the machine that could possibly be an issue...

Except this time. I told the Genius what was wrong. Simply that the screen blinked, has for at least 18 months, and there are complaints with this model. He asked me simply what I meant by "blinked." I showed him the YouTube video someone posted here, and he looked at me, and immediately told me he was opening an order to send my computer offsite to a repair center and they could diagnose and repair this issue for me, as long as I agree...and that my HD may be erased.

I found this odd. I have never had the Genius tell me I had to have something sent off site. Does this mean that (a) they now know of this issue and are keeping it off site for some reason or (b) that they want to know what is happening with this issue and are sending them somewhere to have people who can diagnose this better than Apple because they haven't gotten to the bottom of it? Or am I imagining things? And why erase a hard drive if it's a video issue? I thought that was a strange event, as I have had other repairs much worse than this (my white iMac with video issues) and they NEVER touched my HD.

Any thoughts? In the meantime, when they call back in 3-5 days, I will hopefully have answers and share.