The test igt@gem_sync@basic-all fails on IVB-3770 about 17% of the time (22 of 128).

CPU: IVB-3770
Kernel: drm-tip: 2017y-02m-27d-07h-11m-41s
OS: Fedora 24

Log:
$ sudo ./gem_sync --r basic-all
IGT-Version: 1.17-gd91fec7 (x86_64) (Linux: 4.10.0-CI-CI_DRM_2269_f889c7b+ x86_64)
Using Legacy submission , with semaphores
Completed 54272 cycles: 92.290 us
(gem_sync:10391) CRITICAL: Test assertion failure function sync_all, file gem_sync.c:570:
(gem_sync:10391) CRITICAL: Failed assertion: intel_detect_and_clear_missed_interrupts(fd) == 0
(gem_sync:10391) CRITICAL: error: 4 != 0
Stack trace:
  #0 [__igt_fail_assert+0xf1]
  #1 [sync_all+0x2ba]
  #2 [__real_main722+0x2f3]
  #3 [main+0x33]
  #4 [__libc_start_main+0xf1]
  #5 [_start+0x29]
  #6 [<unknown>+0x29]
Subtest basic-all failed.
**** DEBUG ****
(gem_sync:10391) DEBUG: Test requirement passed: num_engines
(gem_sync:10391) CRITICAL: Test assertion failure function sync_all, file gem_sync.c:570:
(gem_sync:10391) CRITICAL: Failed assertion: intel_detect_and_clear_missed_interrupts(fd) == 0
(gem_sync:10391) CRITICAL: error: 4 != 0
****  END  ****
Subtest basic-all: FAIL (5.047s)