Been getting this in Fedora 23 (+ testing) 64-bit ever since upgrading the hardware.

A desktop system, Intel i7 6700, built-in video, two monitors (HDMI + DVI).

The current kernel is:

Linux fiona 4.4.9-300.fc23.x86_64 #1 SMP Wed May 4 23:56:27 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

[    1.756194] ------------[ cut here ]------------
[    1.756271] WARNING: CPU: 0 PID: 135 at drivers/gpu/drm/i915/intel_pm.c:3601 skl_update_other_pipe_wm+0x1de/0x1f0 [i915]()
[    1.756273] WARN_ON(!wm_changed)
[    1.756285] Modules linked in: i915 e1000e i2c_algo_bit drm_kms_helper uas ptp serio_raw usb_storage pps_core drm nvme video i2c_hid fjes
[    1.756290] CPU: 0 PID: 135 Comm: kworker/u16:3 Not tainted 4.4.9-300.fc23.x86_64 #1
[    1.756292] Hardware name: System manufacturer System Product Name/Z170-A, BIOS 1702 01/28/2016
[    1.756300] Workqueue: events_unbound async_run_entry_fn
[    1.756305]  0000000000000286 000000007d583ed3 ffff88045e1174b0 ffffffff813b62ee
[    1.756308]  ffff88045e1174f8 ffffffffa0220bf8 ffff88045e1174e8 ffffffff810a4252
[    1.756311]  ffff88045e11761c ffff88045ba81000 ffff88045ba80000 0000000000000000
[    1.756312] Call Trace:
[    1.756322]  [<ffffffff813b62ee>] dump_stack+0x63/0x85
[    1.756329]  [<ffffffff810a4252>] warn_slowpath_common+0x82/0xc0
[    1.756333]  [<ffffffff810a42ec>] warn_slowpath_fmt+0x5c/0x80
[    1.756393]  [<ffffffffa015bd6e>] skl_update_other_pipe_wm+0x1de/0x1f0 [i915]
[    1.756448]  [<ffffffffa015bfd2>] skl_update_wm+0x252/0x750 [i915]
[    1.756501]  [<ffffffffa01604de>] intel_update_watermarks+0x1e/0x30 [i915]
[    1.756581]  [<ffffffffa01c8b80>] haswell_crtc_enable+0x370/0x870 [i915]
[    1.756656]  [<ffffffffa01c4712>] intel_atomic_commit+0x492/0x1420 [i915]
[    1.756694]  [<ffffffffa00621ae>] ? drm_atomic_check_only+0x18e/0x590 [drm]
[    1.756727]  [<ffffffffa00625e7>] drm_atomic_commit+0x37/0x60 [drm]
[    1.756742]  [<ffffffffa00f21af>] restore_fbdev_mode+0x22f/0x260 [drm_kms_helper]
[    1.756756]  [<ffffffffa00f4383>] drm_fb_helper_restore_fbdev_mode_unlocked+0x33/0x80 [drm_kms_helper]
[    1.756767]  [<ffffffffa00f43fd>] drm_fb_helper_set_par+0x2d/0x50 [drm_kms_helper]
[    1.756847]  [<ffffffffa01db39a>] intel_fbdev_set_par+0x1a/0x60 [i915]
[    1.756853]  [<ffffffff814283c0>] fbcon_init+0x570/0x5f0
[    1.756858]  [<ffffffff814a9eca>] visual_init+0xca/0x130
[    1.756861]  [<ffffffff814abd61>] do_bind_con_driver+0x1c1/0x3a0
[    1.756865]  [<ffffffff814ac279>] do_take_over_console+0x149/0x1a0
[    1.756870]  [<ffffffff81424227>] do_fbcon_takeover+0x57/0xb0
[    1.756874]  [<ffffffff81428e38>] fbcon_event_notify+0x658/0x750
[    1.756878]  [<ffffffff810c369a>] notifier_call_chain+0x4a/0x70
[    1.756882]  [<ffffffff810c39d7>] __blocking_notifier_call_chain+0x47/0x60
[    1.756885]  [<ffffffff810c3a06>] blocking_notifier_call_chain+0x16/0x20
[    1.756890]  [<ffffffff8142ea8b>] fb_notifier_call_chain+0x1b/0x20
[    1.756896]  [<ffffffff81430daf>] register_framebuffer+0x20f/0x350
[    1.756909]  [<ffffffffa00f46aa>] drm_fb_helper_initial_config+0x28a/0x410 [drm_kms_helper]
[    1.756978]  [<ffffffffa01dbe9b>] intel_fbdev_initial_config+0x1b/0x20 [i915]
[    1.756984]  [<ffffffff810c510a>] async_run_entry_fn+0x4a/0x140
[    1.756988]  [<ffffffff810bc709>] process_one_work+0x159/0x430
[    1.756993]  [<ffffffff810bca2e>] worker_thread+0x4e/0x450
[    1.756997]  [<ffffffff810bc9e0>] ? process_one_work+0x430/0x430
[    1.757000]  [<ffffffff810c27b8>] kthread+0xd8/0xf0
[    1.757003]  [<ffffffff810c26e0>] ? kthread_worker_fn+0x160/0x160
[    1.757008]  [<ffffffff817a128f>] ret_from_fork+0x3f/0x70
[    1.757011]  [<ffffffff810c26e0>] ? kthread_worker_fn+0x160/0x160
[    1.757041] ---[ end trace fafafc83ac3f9b24 ]---