FYI, we noticed the below changes on

git://anongit.freedesktop.org/drm-intel for-linux-next
commit 437b15b8017e0d946453c10794b0c5d4591cf180 ("drm/i915: use pch backlight override on hsw too")


<4>[   25.650730] ------------[ cut here ]------------
<4>[   25.650752] WARNING: CPU: 2 PID: 80 at drivers/gpu/drm/i915/intel_display.c:9234 hsw_enable_pc8+0x60b/0x740 [i915]()
<4>[   25.650753] CPU PWM1 enabled
<4>[   25.650773] Modules linked in: rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver snd_hda_codec_hdmi x86_pkg_temp_thermal coretemp kvm_intel snd_hda_intel kvm crct10dif_pclmul snd_hda_codec snd_hda_core crc32_pclmul snd_hwdep crc32c_intel i915 ghash_clmulni_intel snd_pcm drm_kms_helper snd_timer syscopyarea aesni_intel sysfillrect sdhci_acpi sysimgblt lrw fb_sys_fops gf128mul glue_helper ablk_helper cryptd ppdev drm shpchp snd microcode serio_raw pcspkr soundcore i2c_i801 winbond_cir rc_core i2c_hid sdhci video dw_dmac dw_dmac_core mmc_core parport_pc parport i2c_designware_platform i2c_designware_core acpi_pad spi_pxa2xx_platform
<4>[   25.650775] CPU: 2 PID: 80 Comm: kworker/u16:1 Not tainted 4.2.0-rc8-01085-g437b15b #1
<4>[   25.650776] Hardware name: Intel Corporation Broadwell Client platform/WhiteTip Mountain 1, BIOS BDW-E1R1.86C.0120.R00.1504020241 04/02/2015
<4>[   25.650779] Workqueue: events_unbound async_run_entry_fn
<4>[   25.650781]  ffffffffa0433070 ffff880032b63be8 ffffffff8189e2e9 ffffffff81cf4238
<4>[   25.650783]  ffff880032b63c38 ffff880032b63c28 ffffffff8107348a 00000000fffbca4d
<4>[   25.650784]  ffff88006bc10000 ffff88006d184b70 ffff88006d184b80 ffff88006d184800
<4>[   25.650784] Call Trace:
<4>[   25.650788]  [<ffffffff8189e2e9>] dump_stack+0x4c/0x65
<4>[   25.650791]  [<ffffffff8107348a>] warn_slowpath_common+0x8a/0xc0
<4>[   25.650792]  [<ffffffff81073506>] warn_slowpath_fmt+0x46/0x50
<4>[   25.650808]  [<ffffffffa03d64eb>] hsw_enable_pc8+0x60b/0x740 [i915]
<4>[   25.650814]  [<ffffffffa035a3cb>] intel_suspend_complete+0x65b/0x6e0 [i915]
<4>[   25.650819]  [<ffffffffa035a472>] i915_drm_suspend_late+0x22/0x80 [i915]
<4>[   25.650825]  [<ffffffffa035a5c0>] ? i915_pm_poweroff_late+0x30/0x30 [i915]
<4>[   25.650831]  [<ffffffffa035a5e9>] i915_pm_suspend_late+0x29/0x30 [i915]
<4>[   25.650833]  [<ffffffff81551c1c>] dpm_run_callback+0x4c/0x120
<4>[   25.650835]  [<ffffffff815524c9>] __device_suspend_late+0xa9/0x180
<4>[   25.650837]  [<ffffffff815525bf>] async_suspend_late+0x1f/0xa0
<4>[   25.650838]  [<ffffffff810944ca>] async_run_entry_fn+0x4a/0x140
<4>[   25.650841]  [<ffffffff8108b6e7>] process_one_work+0x157/0x420
<4>[   25.650843]  [<ffffffff8108c1c9>] worker_thread+0x69/0x4a0
<4>[   25.650844]  [<ffffffff8108c160>] ? rescuer_thread+0x380/0x380
<4>[   25.650846]  [<ffffffff8108c160>] ? rescuer_thread+0x380/0x380
<4>[   25.650847]  [<ffffffff8109197f>] kthread+0xef/0x110
<4>[   25.650849]  [<ffffffff81091890>] ? kthread_create_on_node+0x180/0x180
<4>[   25.650851]  [<ffffffff818a621f>] ret_from_fork+0x3f/0x70
<4>[   25.650852]  [<ffffffff81091890>] ? kthread_create_on_node+0x180/0x180
<4>[   25.650853] ---[ end trace 597b97aad370829b ]---

To reproduce:

        git clone git://git.kernel.org/pub/scm/linux/kernel/git/wfg/lkp-tests.git
        cd lkp-tests
        bin/lkp install job.yaml  # job file is attached in this email
        bin/lkp run     job.yaml



Thanks,
Ying Huang