Screen freezes for a few seconds

Hi fizzfitt,

I haven't tried the networking off workaround yet. I'll give it a try this evening.

I too have been frustrated by this issue for the year plus that I have had this MBP in the identical configuration as yours.

I recently took my laptop to Genius Bar and the Apple diagnostics reported NO hardware issues. I am now 100% convinced this is a software issue. The freeze issue did not occur when booted in Sierra 10.12. It began to occur under High Sierra 10.13 and continues with Mojave 10.14.

Apple said that there was nothing wrong according to the diagnostic, but offered me the $600 flat rate repair service anyway. I declined.

There are way too many other users reporting the identical console fault messages for this to be unknown to Apple.

The clock and trackpad freeze but Videos and/or Music will continue to play uninterrupted. I get the identical six Console entries every time the freeze occurs. This freeze is random. Either once or twice a day or sometimes 5-10 times per hour.

1 0: 0x5c3da 0x5c3da 0 0 fault 2018-09-22 23:51:06.033976 -0400 IOAcceleratorFamily2 virtual IOReturn IOAccelEventMachine2::waitForStamp(int32_t, stamp_t, stamp_t *): initial wait for 1 second expired. Continue wait for 4 seconds. stamp 189181 (gpu_stamp=189180) kernel

1 0: 0x5c3da 0x5c3da 0 0 fault 2018-09-22 23:51:10.034928 -0400 IOAcceleratorFamily2 virtual IOReturn IOAccelEventMachine2::waitForStamp(int32_t, stamp_t, stamp_t *): timeout waiting for IntelAccelerator stamp 189181 (gpu_stamp=189180) kernel

1 0: 0x5c3da 0x5c3da 0 0 fault 2018-09-22 23:51:10.034959 -0400 IOAcceleratorFamily2 void IOAccelEventMachine2::handleFinishChannelRestart(IOReturn, int32_t, uint32_t) - Setting restart type to 4 kernel

1 0: 0x5c3da 0x5c3da 0 0 fault 2018-09-22 23:51:10.034968 -0400 IOAcceleratorFamily2 void IOAccelEventMachine2::handleFinishChannelRestart(IOReturn, int32_t, uint32_t): GPURestartDequeued stampIdx=4 type=4 fromWhere=1 waitingOnIdx=4 kernel

1 0: 0x5c3da 0x5c3da 0 0 fault 2018-09-22 23:51:10.035032 -0400 IOAcceleratorFamily2 void IOAccelEventMachine2::restart_channel(): GPURestartSkipped stampIdx=4 type=4 kernel

1 0: 0x5c3da 0x5c3da 0 0 fault 2018-09-22 23:51:10.035038 -0400 IOAcceleratorFamily2 void IOAccelEventMachine2::restart_channel(): no channel associated with stamp_idx 4 (type 4)

Good luck on your talk with Apple!

Thank you

What all did you install for software after your clean install of MacOS?

I tried to use my Mac for a few hours before adding more software (especially things not from the App Store). There are a lot of things, that I had on my Mac previously, that I have not reinstalled at all yet (and plenty that I probably won't unless I absolutely need them). It did take a few days to get the things I do need back on there and working the way I wanted them again.

It has been over a week for me and I have still not seen the IOAccelEventMachine2::waitForStamp error since my clean install.

I've found a consistent correlation between having a browser window open in the background, to a video streaming service like Netflix or Amazon Prime, and this error. I have also noticed a correlation between the error and browser windows that have video frames in them. So if a webpage has a video-heavy ad or something, this error will crop up sometimes. I don't get it if all browser windows are closed. And I don't think I've seen it if I don't have video in one of my browser tabs somewhere.

The longer I watch it, and the more I read other people's reporting about it, the more it looks to me like a GPU load balancing fault.

Basically, the fault only seems to occur when it's under a heavy graphics load, while it's doing something else.

Are you sure you're having the same kind of freeze problem? Have you checked the Console and found the same IOAccelEventMachine debug output?

I've solved the problem as others have done by not keeping Safari open. I used to have many of windows with dozens of tabs open all the time, one window for each task or project I work on. I've now changed that and moved everything into bookmarks, with only one or two active windows and half a dozen tabs.

I also have/had the problem.

I changed in the Fotos.app from "optimize mac storage" to "download originals to this mac" and the error did not occur again.

Maybe you also should disable the "optimize mac storage" in the iCloud / iCloud Drive if you habe enabled it.

Hey @apple have a look at that ;-)

Cheers

Abdul

I've just recently started experiencing this issue on my mid-2015 MBPro. It coincided with an install of the recent Xcode beta, but that alone didn't make sense as this thread predates that by a year or more. Last night I realised that since around that time, I'd been keeping Safari with a number of WWDC session tabs open, waiting to download a selection of videos as they became available. I've been experiencing multiple temporary freezes per day over this entire period. Last night I closed Safari and have not re-opened it, and the problem has not occurred since, with all other usage being typical of my day. I generally do not use Safari at all.

This is hardly conclusive, and I will be keeping a close eye on things over the coming days, but I wanted to share the observation just in case.

For 90 seconds I never heard of that (nor experienced that). Even in the log it basically fail after 1 second, than wait for an extra 4 seconds (so total 5 seconds). That's pretty much the freeze time that I experience.

As for me, I restarted using Safari and the freeze came back within a day. So after 2 weeks of using Chrome and no lag, it restarted basically the next day I restarted using Safari. It might be a coincidence, but anyway, back on Chrome for now and no more lag again. Chrome is also much faster anyway, so I think I will just settle with that and report back if the freeze ever happen again.

Hi robogobo,

Apple introduced this bug with High Sierra (10.13) and has yet to fix it on any update through the current version of Catalina. I gave up and went back to Sierra (10.12.6) and haven't had the "IOReturn IOAccelEventMachine2" error since on similar hardware:

Model Name: MacBook Pro

  Model Identifier: MacBookPro11,4

  Processor Name: Intel Core i7

  Processor Speed: 2.2 GHz

  Number of Processors: 1

  Total Number of Cores: 4

  L2 Cache (per Core): 256 KB

  L3 Cache: 6 MB

  Memory: 16 GB

  Boot ROM Version: 194.0.0.0.0

  SMC Version (system): 2.29f24

Apple does know about the issue as many posters to these community pages have uploaded full bug/crash reports. However, it does appear that they will not or cannot fix the issue for whatever reason. If you submit a bug/crash report they eventually come back to you saying it's a "duplicate report" and never answer your follow ups. Very frustrating!!!

Like anerdinseattle wrote: If I just run my daily applications (Safari closed, no video running in background) then no freezes for days and weeks appears.

The problem seem to have been fixed on the latest update at least on my MacBook Pro of mid 2014 after Mac OS X 10.14.5.

It was so annoying!

Yeah - it appears to occur if Safari has > ~15 tabs open. Restarting Safari resolves the issue. Strange.

The only 100% fix is to install 10.12.6. We will never get a fix from apple for any Mac OS later than 10.12.6 on our 2015 15” MBP’s.