i915 WARNING: Missing switch case (16) in gen6_check_mailbox_status

[Meelis Roos]

Tried 4.8-rc4 on my i5-2400 PC, got this warning:

[   14.579557] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
[   15.847321] ------------[ cut here ]------------
[   15.847346] WARNING: CPU: 0 PID: 208 at drivers/gpu/drm/i915/intel_pm.c:7866 sandybridge_pcode_write+0x109/0x1f0 [i915]
[   15.847348] Missing switch case (16) in gen6_check_mailbox_status
[   15.847349] Modules linked in: cpufreq_powersave cpufreq_userspace cpufreq_conservative joydev hid_generic usbhid hid x86_pkg_temp_thermal kvm_intel kvm irqbypass crc32c_intel aesni_intel snd_hda_codec_realtek snd_hda_codec_generic iTCO_wdt i915 aes_x86_64 iTCO_vendor_support glue_helper lrw ablk_helper cryptd video i2c_algo_bit drm_kms_helper psmouse pcspkr syscopyarea sysfillrect sysimgblt fb_sys_fops ehci_pci ehci_hcd snd_hda_intel xhci_pci xhci_hcd e1000e snd_hda_codec snd_hwdep usbcore drm snd_hda_core usb_common i2c_i801 ptp pps_core i2c_smbus snd_pcm_oss snd_mixer_oss snd_pcm snd_timer evdev snd tpm_tis lpc_ich parport_pc tpm_tis_core mfd_core parport nuvoton_cir rc_core tpm soundcore floppy w83627ehf hwmon_vid coretemp hwmon eeprom i2c_core loop ip_tables x_tables autofs4
[   15.847395] CPU: 0 PID: 208 Comm: kworker/0:2 Not tainted 4.8.0-rc4 #213
[   15.847396] Hardware name:                  /DQ67OW, BIOS SWQ6710H.86A.0066.2012.1105.1504 11/05/2012
[   15.847412] Workqueue: events intel_gen6_powersave_work [i915]
[   15.847414]  0000000000000000 ffffffff812d8198 ffff88023191fd70 0000000000000000
[   15.847417]  ffffffff81056d1e ffff88022ea40000 ffff88023191fdc0 0000000000000000
[   15.847419]  ffff88022ea4a3c8 ffff88022ea487c0 0ffff88023e21ba0 ffffffff81056d8f
[   15.847422] Call Trace:
[   15.847427]  [<ffffffff812d8198>] ? dump_stack+0x46/0x5e
[   15.847429]  [<ffffffff81056d1e>] ? __warn+0xbe/0xe0
[   15.847431]  [<ffffffff81056d8f>] ? warn_slowpath_fmt+0x4f/0x60
[   15.847446]  [<ffffffffa0311a09>] ? sandybridge_pcode_write+0x109/0x1f0 [i915]
[   15.847459]  [<ffffffffa0313308>] ? intel_gen6_powersave_work+0x2a8/0x1400 [i915]
[   15.847462]  [<ffffffff8106e4db>] ? process_one_work+0x1eb/0x480
[   15.847465]  [<ffffffff8106e7b7>] ? worker_thread+0x47/0x4c0
[   15.847467]  [<ffffffff815649f7>] ? __schedule+0x1d7/0x660
[   15.847469]  [<ffffffff8106e770>] ? process_one_work+0x480/0x480
[   15.847472]  [<ffffffff8107398d>] ? kthread+0xbd/0xe0
[   15.847475]  [<ffffffff8156903f>] ? ret_from_fork+0x1f/0x40
[   15.847478]  [<ffffffff810738d0>] ? kthread_worker_fn+0x160/0x160
[   15.847487] ---[ end trace ad9e991297d99be1 ]---

-- 
Meelis Roos (mroos at linux.ee)