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Fixed in future release



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Issue ID




[iOS][Metal] GPU Hang Error (IOAF code 3) in Xcode Console




Priority: 2Necessary for shipping a final release


Severity: 1Crash or major loss of functionality

Errors appear in the Xcode Console when User's project is run on iOS:
2017-04-19 12:55:18.131719+0300 KneeViewer[346:45705] Execution of the command buffer was aborted due to an error during execution. Caused GPU Hang Error (IOAF code 3)

Steps to reproduce:
1. Open User's attached project
2. Make sure the Graphics APIs is set to Metal
3. Run on iPad

Result: Errors appear in the Xcode Console: 2017-04-19 12:55:18.131719+0300 KneeViewer[346:45705] Execution of the command buffer was aborted due to an error during execution. Caused GPU Hang Error (IOAF code 3). iPad screen is black.

Reproduced with: 5.6.0f3, 5.6.0p2
Not reproduced with: 2017.1.0b1 (due to errors in the Console), 5.5.3f1 (works as expected).

Tested with:
iPad Mini 2 | iOS10.3.1 | reproduced
iPad Mini 2 | iOS10.2.1 | not reproduced
iPad Mini 4 | iOS9.3.2 | not reproduced
iPad Pro | iOS10.2 | not reproduced
iPhone 6 | iOS10.3.1 | not reproduced
iPhone 6S | iOS10.3 | not reproduced

Workaround: change graphics API to OpenGLES2 or OpenGLES3.

Note: the issue only reproduces on Metal.

Comments (9)

  1. 9c5e2c5ea480b256ffa813b2874f82d7?d=mm


    May 22, 2017 07:45

    This was fixed for my repro in previous comment on 5.6.1p1

  2. 9c5e2c5ea480b256ffa813b2874f82d7?d=mm


    May 15, 2017 11:33

    I found I could repro this problem on 5.6.0f3 and 5.6.1f1 with iPhone 5S running iOS 10.3.1 but couldn't repro with a 5S running 9.3.2. Turning off anti-aliasing on the RenderTexture we were using on the problematic device as zilppuri suggested is a possible workaround while still using Metal.

  3. 05b25e4b075139c9c0602f9a41f89245?d=mm


    May 14, 2017 23:50

    Updated to Unity v5.6.1f1. No post effects, Metal still crashing our iOS devices (iOS 10.3.1, iPhone 5S, iPad Air).

  4. 599287585fe5fb950fd8b551ecee03a9?d=mm


    May 08, 2017 23:16

    Tested with 5.6.0p4. The bug ist still present. Update: I was able to construct a simple post-effect that does not stop the rendering, so things seem to be a little more complicated than expected. With others, the screen does not get black but keeps the framebuffer in combination with some flickering. I consider this a rather severe bug for iOS. The only solution is to disable post effects for iPad air 2, iPad mini 2 & 3 and tvOS in general, which is a really really ugly and unpleasant fix.

  5. Cba834be3b84bfc8f492ce90da32964a?d=mm


    May 04, 2017 23:11

    Happens on an iPad Mini 3 for us. Please fix this.

  6. 1e6a73ce1c3738a00344d75dcd86526c?d=mm


    May 01, 2017 18:31

    For us this happens on iPad Air 2 and Apple TV Gen 4 which both have some variant of A8 chip

  7. 1eda1020233c98c7b40307a52ca36f09?d=mm


    Apr 28, 2017 17:02

    The game doesn't hang if I switch off Anti-aliasign. Seems this is a way to circumvent the issue for now - with a loss in graphical quality.

  8. 6d8c02bfc2ccac4ca5e25fde797639aa?d=mm


    Apr 28, 2017 10:56

    Switching to OpenGLES3 fixed this problem for Ipad but Iphone6 running iOs 10.3 has the same problem.

  9. 4248a6bae6f0d7f93461856db84fc34c?d=mm


    Apr 27, 2017 14:48

    I get this error on iPad Air 2 as well, where it reliably appears whenever a post-effect is enabled. Watched it once on iPad pro as well, could not reproduce it, however.

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