For reference, these are expected to run in a couple of seconds.

Created attachment 122299 [details]
bsw-dmesg-gem_pwrite-big-gtt

Tested on BSW.
big-cpu is Pass after around 20 minutes.
big-gtt is fail.

# ./gem_pwrite --run-subtest big-cpu
IGT-Version: 1.14-NOT-GIT (x86_64) (Linux: 4.4.0-nightly x86_64)
Subtest big-cpu: SUCCESS (1207.723s)

# ./gem_pwrite --run-subtest big-gtt
IGT-Version: 1.14-NOT-GIT (x86_64) (Linux: 4.4.0-nightly x86_64)
(gem_pwrite:1620) ioctl-wrappers-CRITICAL: Test assertion failure function gem_write, file ioctl_wrappers.c:321:
(gem_pwrite:1620) ioctl-wrappers-CRITICAL: Failed assertion: drmIoctl((fd), ((((1U) << (((0+8)+8)+14)) | ((('d')) << (0+8)) | (((0x40 + 0x1d)) << 0) | ((((sizeof(struct drm_i915_gem_pwrite)))) << ((0+8)+8)))), (&gem_pwrite)) == 0
(gem_pwrite:1620) ioctl-wrappers-CRITICAL: Last errno: 7, Argument list too long
(gem_pwrite:1620) ioctl-wrappers-CRITICAL: error: -1 != 0
Stack trace:
  #0 [__igt_fail_assert+0xf1]
  #1 [gem_read+0x0]
  #2 [test_big_gtt+0xff]
  #3 [main+0x6b7]
  #4 [__libc_start_main+0xf5]
  #5 [_start+0x29]
  #6 [<unknown>+0x29]
Subtest big-gtt failed.
**** DEBUG ****
(gem_pwrite:1620) intel-os-DEBUG: Checking 1 surfaces of size 1,610,612,736 bytes (total 1,610,616,832) against RAM
(gem_pwrite:1620) intel-os-DEBUG: Test requirement passed: !(!__intel_check_memory(count, size, mode, &required, &total))
(gem_pwrite:1620) igt-core-DEBUG: Test requirement passed: !igt_run_in_simulation()
(gem_pwrite:1620) DEBUG: Test requirement passed: gem_mmap__has_wc(fd)
(gem_pwrite:1620) ioctl-wrappers-CRITICAL: Test assertion failure function gem_write, file ioctl_wrappers.c:321:
(gem_pwrite:1620) ioctl-wrappers-CRITICAL: Failed assertion: drmIoctl((fd), ((((1U) << (((0+8)+8)+14)) | ((('d')) << (0+8)) | (((0x40 + 0x1d)) << 0) | ((((sizeof(struct drm_i915_gem_pwrite)))) << ((0+8)+8)))), (&gem_pwrite)) == 0
(gem_pwrite:1620) ioctl-wrappers-CRITICAL: Last errno: 7, Argument list too long
(gem_pwrite:1620) ioctl-wrappers-CRITICAL: error: -1 != 0
****  END  ****
Subtest big-gtt: FAIL (1.207s)


Hardware: 
Motherboard: Aspire XC-704 
cpu model name : Intel(R) Pentium(R) CPU N3700 @ 1.60GHz 
cpu model : 76 
cpu family : 6 
Graphic card: Device 22b1 (rev 21)

Software:
Bios: R01-A2
Kernel mainline 4.4.0 from https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
  commit afd2ff9b7e1b367172f18ba7f693dfb62bdcb2dc
  Author: Linus Torvalds <torvalds@linux-foundation.org>
  Date:   Sun Jan 10 15:01:32 2016 -0800
  Linux 4.4
drm: libdrm-2.4.67-5 ea07de9 from git://anongit.freedesktop.org/mesa/drm
mesa: tag mesa-11.1.2 7bcd827 from git://anongit.freedesktop.org/mesa/mesa
cairo: tag 1.15.2 db8a7f1 from git://anongit.freedesktop.org/cairo
waffle: master bb29b2a from git://github.com/waffle-gl/waffle
xorg-server-macros: tag: util-macros-1.19.0-2 d7acec2 from git://git.freedesktop.org/git/xorg/util/macros
xserver: tag: xorg-server-1.18.1 23e60f9 from git://git.freedesktop.org/git/xorg/xserver
xf86-video-intel: tag 2.99.917-560 d167280 from git://anongit.freedesktop.org/xorg/driver/xf86-video-intel
libva: tag libva-1.7.0.pre1 35f1447 from git://git.freedesktop.org/git/vaapi/libva
vaapi-intel-driver: tag 1.7.0.pre1 ab8e4e3 from git://anongit.freedesktop.org/vaapi/intel-driver
IGT 1.14 364d378 from http://anongit.freedesktop.org/git/xorg/app/intel-gpu-tools.git

One external screen connected to HDMI

Same behavior on BSW with following subcases:
igt@gem_pwrite@big-cpu-random
igt@gem_pwrite@big-cpu-forwards
igt@gem_pwrite@big-cpu-backwards
igt@gem_pwrite@big-gtt-random
igt@gem_pwrite@big-gtt-backwards
igt@gem_pwrite@big-gtt-forwards
igt@gem_pwrite@big-gtt-fbr

Configuration:

Configuration:


============================================ 
Kernel version              	: 4.7.0-040700rc2-generic 
Linux distribution          	: Ubuntu 16.04 LTS 
Architecture                	: 64-bit 
Mesa version                	: 11.2.2
xf86-video-intel version    	: 2.99.917 
Xorg-Xserver version        	: 1.18.3 
DRM version                 	: 2.4.67 
VAAPI version               	: Intel i965 driver for Intel(R) CherryView - 1.7.0 
Cairo version               	: [1m[1;31mNot found[0m 
Intel GPU Tools version     	: 1.15-1 <-- [1;33mThis is a generic version of IGT[0m 
Kernel driver in use        	: [1m[1;32mi915[0m 
Hardware acceleration        	:  
Bios revision               	: 4.0 
KSC revision                	: [1m[1;31mNot found[0m <-- [1;33mmaybe the DUT doesn't has this firmware[0m 


 [1m[1;34mHardware information[0m 
============================================ 
Platform                     	:  
Motherboard model            	: Inspiron 15-3552 
Motherboard type             	: 0T14MC Portable 
Motherboard manufacturer     	: Dell Inc. 
CPU family                   	: Pentium 
CPU information              	: Intel(R) Pentium(R) CPU  N3700  @ 1.60GHz 
GPU Card                     	: Intel Corporation Device 22b1 (rev 21) (prog-if 00 [VGA controller]) 
Memory ram                   	: 4 GB 
Maximum memory ram allowed   	: 8 GB 
Display resolution       	:  
CPU's number             	: 4 
Hard drive Capacity 		: 128 GB

commit 96d776345277d81dc96e984f13d8f2b84ab0dee4
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Fri Oct 28 13:58:33 2016 +0100

    drm/i915: Use a radixtree for random access to the object's backing storage