Xorg crashes on systemctl suspend

[Jocelyn]

Xorg always crashes on Ubuntu 15.10 when trying to do systemctl suspend. Here is the Xorg.0.log.old:

[ 15.924] (EE) Backtrace:
[ 15.925] (EE) 0: /usr/bin/X (xorg_backtrace+0x4e) [0x55d2ea6c268e]
[ 15.925] (EE) 1: /usr/bin/X (0x55d2ea50e000+0x1b89f9) [0x55d2ea6c69f9]
[ 15.925] (EE) 2: /lib/x86_64-linux-gnu/libc.so.6 (0x7f80eb640000+0x352f0) [0x7f80eb6752f0]
[ 15.925] (EE) 3: /usr/lib/x86_64-linux-gnu/libpciaccess.so.0 (pci_device_vgaarb_set_target+0xf3) [0x7f80ecc34933]
[ 15.925] (EE) 4: /usr/bin/X (0x55d2ea50e000+0xb8c10) [0x55d2ea5c6c10]
[ 15.925] (EE) 5: /usr/bin/X (0x55d2ea50e000+0x96630) [0x55d2ea5a4630]
[ 15.925] (EE) 6: /usr/bin/X (DPMSSet+0x76) [0x55d2ea5a4926]
[ 15.925] (EE) 7: /usr/bin/X (0x55d2ea50e000+0x10f8d4) [0x55d2ea61d8d4]
[ 15.925] (EE) 8: /usr/bin/X (0x55d2ea50e000+0x5818f) [0x55d2ea56618f]
[ 15.925] (EE) 9: /usr/bin/X (0x55d2ea50e000+0x5c34b) [0x55d2ea56a34b]
[ 15.925] (EE) 10: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xf0) [0x7f80eb660a40]
[ 15.925] (EE) 11: /usr/bin/X (_start+0x29) [0x55d2ea5546c9]
[ 15.925] (EE)
[ 15.925] (EE) Segmentation fault at address 0x30
[ 15.925] (EE)
Fatal server error:
[ 15.925] (EE) Caught signal 11 (Segmentation fault). Server aborting

I'm using i3 and lightdm, kernel 4.5.0, and an Ivy Bridge i7-3547u. This is a possible duplicate of https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1510998 but the stacktrace isn't the same. I can't pinpoint when it started to happen. I also tried all the fix proposed, both using UXA instead of SNA, or updating the Xorg driver. The problem persists with the oibaf ppa.