Hi,

I got below Call Trace when booting my 4.3.0-rc3+ kernel on my SKL DT 
machine. Although my machine boots up despite this call trace, I think 
it's better to report it (and hopefully this is the right mailing list 
to report).

I disabled C status and P status in BIOS for my machine. I also attached 
my .config for building kernel/modules for your reference.

[    8.455630] [drm] Replacing VGA console driver
[    8.466039] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[    8.470056] hid-generic 0003:03F0:0324.0002: input,hidraw1: USB HID 
v1.10 Keyboard [Lite-On Technology Corp. HP Basic USB Keyboard] on 
usb-0000:00:14.0-9/input0
[    8.487212] [drm] Driver supports precise vblank timestamp query.
[    8.497847] vgaarb: device changed decodes: 
PCI:0000:00:02.0,olddecodes=io+mem,decodes=io+mem:owns=io+mem
[    9.268642] [drm] failed to retrieve link info, disabling eDP
[    9.275089] ------------[ cut here ]------------
[    9.279795] WARNING: CPU: 0 PID: 172 at 
drivers/gpu/drm/i915/intel_pm.c:3321 skl_update_pipe_wm+0x82b/0x840 [i915]()
[    9.290478] WARN_ON(p->pixel_rate == 0)
[    9.294109] Modules linked in: hid_generic usbhid i915(+) e1000e 
i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt 
fb_sys_fops drm ptp i2c_hid ahci wmi pps_core libahci pinctrl_sunrisepoinl
[    9.314929] CPU: 0 PID: 172 Comm: systemd-udevd Not tainted 4.3.0-rc3+ #4
[    9.321822] Hardware name: Intel Corporation Skylake Client 
platform/Skylake DT DDR4 RVP8, BIOS SKLSE2R1.R00.B089.B00.1506160228 
06/16/2015
[    9.334533]  0000000000000000 000000003859d50b ffff88023f6c3390 
ffffffff813bd1c4
[    9.342101]  ffff88023f6c33d8 ffff88023f6c33c8 ffffffff8107bf12 
0000000000000000
[    9.349673]  ffff88023f6c36b6 0000000000000002 ffff88023f6c36b0 
0000000000000007
[    9.357153] Call Trace:
[    9.359714]  [<ffffffff813bd1c4>] dump_stack+0x44/0x60
[    9.364935]  [<ffffffff8107bf12>] warn_slowpath_common+0x82/0xc0
[    9.371033]  [<ffffffff8107bfac>] warn_slowpath_fmt+0x5c/0x80
[    9.376878]  [<ffffffffc01f45eb>] skl_update_pipe_wm+0x82b/0x840 [i915]
[    9.383602]  [<ffffffffc01f4b14>] skl_update_wm+0x154/0x740 [i915]
[    9.389877]  [<ffffffff813c8fcd>] ? vsnprintf+0x17d/0x530
[    9.395362]  [<ffffffff81217135>] ? __d_alloc+0x25/0x170
[    9.400767]  [<ffffffffc01f5193>] skl_update_sprite_wm+0x93/0x100 [i915]
[    9.407580]  [<ffffffffc01f92e2>] 
intel_update_sprite_watermarks+0x32/0x40 [i915]
[    9.415192]  [<ffffffffc02688f2>] skl_disable_plane+0xc2/0xe0 [i915]
[    9.421660]  [<ffffffffc025c3cd>] 
intel_modeset_setup_hw_state+0x42d/0xd90 [i915]
[    9.429272]  [<ffffffffc025e980>] intel_modeset_init+0xb60/0x1ab0 [i915]
[    9.436095]  [<ffffffffc0295fb0>] i915_driver_load+0xcd0/0x1410 [i915]
[    9.442634]  [<ffffffff8170c107>] ? 
netlink_broadcast_filtered+0x137/0x3b0
[    9.449684]  [<ffffffff813c0610>] ? cleanup_uevent_env+0x10/0x10
[    9.455696]  [<ffffffff813c09bb>] ? kobject_uevent_env+0x15b/0x640
[    9.462041]  [<ffffffff81511377>] ? get_device+0x17/0x20
[    9.467437]  [<ffffffff815175e5>] ? klist_class_dev_get+0x15/0x20
[    9.473624]  [<ffffffff817d4d47>] ? klist_node_init+0x37/0x50
[    9.479458]  [<ffffffff817d4dd0>] ? klist_add_tail+0x20/0x50
[    9.485203]  [<ffffffff81513093>] ? device_add+0x233/0x670
[    9.490691]  [<ffffffffc00a4ff7>] drm_dev_register+0xa7/0xb0 [drm]
[    9.497034]  [<ffffffffc00a7d9d>] drm_get_pci_dev+0x8d/0x1e0 [drm]
[    9.503322]  [<ffffffffc01e41e4>] i915_pci_probe+0x34/0x50 [i915]
[    9.509420]  [<ffffffff8140bb25>] local_pci_probe+0x45/0xa0
[    9.515149]  [<ffffffff8140cf63>] pci_device_probe+0x103/0x150
[    9.521072]  [<ffffffff81516772>] driver_probe_device+0x222/0x490
[    9.527260]  [<ffffffff81516a64>] __driver_attach+0x84/0x90
[    9.532919]  [<ffffffff815169e0>] ? driver_probe_device+0x490/0x490
[    9.539284]  [<ffffffff8151439c>] bus_for_each_dev+0x6c/0xc0
[    9.545031]  [<ffffffff81515f2e>] driver_attach+0x1e/0x20
[    9.550513]  [<ffffffff81515a6b>] bus_add_driver+0x1eb/0x280
[    9.556259]  [<ffffffff81517300>] driver_register+0x60/0xe0
[    9.561920]  [<ffffffff8140b4ec>] __pci_register_driver+0x4c/0x50
[    9.568110]  [<ffffffffc00a7fd0>] drm_pci_init+0xe0/0x110 [drm]
[    9.574121]  [<ffffffffc02fb000>] ? 0xffffffffc02fb000
[    9.579348]  [<ffffffffc02fb0a4>] i915_init+0xa4/0xab [i915]
[    9.585096]  [<ffffffff81002123>] do_one_initcall+0xb3/0x200
[    9.590845]  [<ffffffff811c2b61>] ? __vunmap+0x91/0xe0
[    9.596063]  [<ffffffff811df3e7>] ? kmem_cache_alloc_trace+0x187/0x1f0
[    9.602694]  [<ffffffff81181694>] ? do_init_module+0x27/0x1e5
[    9.608528]  [<ffffffff811816cc>] do_init_module+0x5f/0x1e5
[    9.614100]  [<ffffffff8110290a>] load_module+0x21ba/0x27f0
[    9.619828]  [<ffffffff810febe0>] ? __symbol_put+0x60/0x60
[    9.625399]  [<ffffffff81204300>] ? kernel_read+0x50/0x80
[    9.630882]  [<ffffffff81103189>] SyS_finit_module+0xb9/0xf0
[    9.636629]  [<ffffffff817e1af6>] entry_SYSCALL_64_fastpath+0x16/0x75
[    9.643166] ---[ end trace bc7f2684b5881a6e ]---
[    9.647866] [drm:drm_calc_timestamping_constants [drm]] *ERROR* crtc 
21: Can't calculate constants, dotclock = 0!
[    9.662145] ACPI: Video Device [GFX0] (multi-head: yes  rom: no post: no)
[    9.669550] acpi device:15: registered as cooling_device5
[    9.675089] input: Video Bus as 
/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/LNXVIDEO:00/input/input6
[    9.684414] [drm] Initialized i915 1.6.0 20150731 for 0000:00:02.0 on 
minor 0
[    9.700583] fbcon: inteldrmfb (fb0) is primary device
[    9.761699] Console: switching to colour frame buffer device 210x65
[    9.779880] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
[    9.867693] EXT4-fs (sda2): mounted filesystem with ordered data 
mode. Opts: (null)

Thanks,
-Kai