Linux 4.8-rc?: WARNING: at drivers/gpu/drm/i915/intel_pm.c:7866 sandybridge_pcode_write Missing switch case (16) in gen6_check_mailbox_status

[linux at eikelenboom.it]

L.S.,

Since one of the last 4.8 RC's i'm getting the warning below when 
booting on my sandybridge based thinkpad.
 From what it seems the machine still works fine though.

--
Sander

[    2.846265] ------------[ cut here ]------------
[    2.846280] WARNING: CPU: 0 PID: 4 at 
drivers/gpu/drm/i915/intel_pm.c:7866 sandybridge_pcode_write+0x104/0x1e0
[    2.846282] Missing switch case (16) in gen6_check_mailbox_status
[    2.846284] Modules linked in:
[    2.846289] CPU: 0 PID: 4 Comm: kworker/0:0 Not tainted 
4.8.0-rc5-x220-20160905+ #1
[    2.846290] Hardware name: LENOVO 42912ZU/42912ZU, BIOS 8DET69WW 
(1.39 ) 07/18/2013
[    2.846297] Workqueue: events intel_gen6_powersave_work
[    2.846302]  0000000000000000 ffffffff8138bd84 ffff88030fd7bd78 
0000000000000000
[    2.846305]  ffffffff81062d84 ffff88030d490000 ffff88030fd7bdc8 
0000000000000000
[    2.846308]  ffff88030d49a438 ffff88030d498830 0000000000000000 
ffffffff81062dea
[    2.846309] Call Trace:
[    2.846319]  [<ffffffff8138bd84>] ? dump_stack+0x5c/0x78
[    2.846324]  [<ffffffff81062d84>] ? __warn+0xb4/0xd0
[    2.846328]  [<ffffffff81062dea>] ? warn_slowpath_fmt+0x4a/0x50
[    2.846333]  [<ffffffff814edf44>] ? 
sandybridge_pcode_write+0x104/0x1e0
[    2.846338]  [<ffffffff814eefd3>] ? 
intel_gen6_powersave_work+0x2a3/0x1400
[    2.846344]  [<ffffffff810781ea>] ? process_one_work+0x1ba/0x3d0
[    2.846348]  [<ffffffff81078445>] ? worker_thread+0x45/0x4e0
[    2.846351]  [<ffffffff81078400>] ? process_one_work+0x3d0/0x3d0
[    2.846355]  [<ffffffff8107d678>] ? kthread+0xb8/0xd0
[    2.846362]  [<ffffffff817cc8df>] ? ret_from_fork+0x1f/0x40
[    2.846365]  [<ffffffff8107d5c0>] ? kthread_worker_fn+0x180/0x180
[    2.846368] ---[ end trace da7b2ca8a6654bfa ]---