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Fixed in Unity 2017.2



Found in


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 (12)

  1. 458e6f3b18dcc95d0cfa1fdcce21652c?d=mm


    Jun 06, 2017 07:09

    in 5.6.1 p2 having the issue

  2. 35409e483b3db72f1bb04f37fd891f95?d=mm


    Jun 02, 2017 04:25

    Having this issue on 5.6.1f1

  3. 8c120e7335a5129f19ebb1e35d64e8da?d=mm


    Jun 01, 2017 00:51

    can confirm not using AA fixes it on metal in my case

  4. 9c5e2c5ea480b256ffa813b2874f82d7?d=mm


    May 22, 2017 07:45

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

  5. 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.

  6. 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).

  7. 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.

  8. Cba834be3b84bfc8f492ce90da32964a?d=mm


    May 04, 2017 23:11

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

  9. 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

  10. 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.

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