[Nouveau] NVAC: WARN_ON(nvbo->pin_refcnt > 0);

[poma]

Hello fellows!

Signal finally goes through ION's HDMI,
however
# chvt from 5 "graphical" to 3 "textual",
and then at the very end of reboot,
WARN emerges:
...
nouveau 0000:01:00.0: DRM: EVO timeout
------------[ cut here ]------------
WARNING: CPU: 1 PID: 701 at drivers/gpu/drm/nouveau/nouveau_bo.c:137 nouveau_bo_del_ttm+0x7f/0x90 [nouveau]
Modules linked in: ... nouveau mxm_wmi video i2c_algo_bit ttm drm_kms_helper drm wmi ...
CPU: 1 PID: 701 Comm: Xorg Not tainted 4.10.0-0.rc8.git0.1.fc26.x86_64 #1
...
Call Trace:
 dump_stack+0x63/0x84
 __warn+0xcb/0xf0
 warn_slowpath_null+0x1d/0x20
 nouveau_bo_del_ttm+0x7f/0x90 [nouveau]
 ttm_bo_release_list+0xd7/0x1e0 [ttm]
 ttm_bo_release+0x19c/0x250 [ttm]
 ttm_bo_unref+0x23/0x30 [ttm]
 nouveau_gem_object_del+0x8f/0xe0 [nouveau]
 drm_gem_object_free+0x29/0x70 [drm]
 drm_gem_object_unreference_unlocked+0x34/0x80 [drm]
 drm_gem_object_handle_unreference_unlocked+0x69/0xc0 [drm]
 drm_gem_object_release_handle+0x53/0x90 [drm]
 ? drm_gem_object_handle_unreference_unlocked+0xc0/0xc0 [drm]
 idr_for_each+0xa4/0x100
 ? nouveau_abi16_fini+0x50/0x70 [nouveau]
 drm_gem_release+0x20/0x30 [drm]
 drm_release+0x33d/0x390 [drm]
 __fput+0xdf/0x1e0
 ____fput+0xe/0x10
 task_work_run+0x76/0x90
 do_exit+0x2d0/0xb70
 ? __do_page_fault+0x267/0x4c0
 do_group_exit+0x47/0xb0
 SyS_exit_group+0x14/0x20
 entry_SYSCALL_64_fastpath+0x1a/0xa9
RIP: 0033:0x7fa5510acdd8
RSP: 002b:00007fff4a0cb608 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007fa5536839a0 RCX: 00007fa5510acdd8
RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
RBP: 00007fff4a0cb600 R08: 00000000000000e7 R09: fffffffffffffc88
R10: 00007fa552bf5d80 R11: 0000000000000246 R12: 00007fa552bf5d68
R13: 000000000000004a R14: 0000000000000000 R15: 00007fff4a0cb2f0
---[ end trace 53f6d91de8e38281 ]---

Ref.
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/nouveau/nouveau_bo.c?id=refs/tags/v4.10-rc8#n137