intel_check_page_flip() - WARN_ON(!in_interrupt())

[Shuah Khan <shuahkh@osg.samsung.com>]

I am seeing the following in the dmesg on 4.0.4 with rt patch

[    5.720319] ------------[ cut here ]------------
[    5.720347] WARNING: CPU: 6 PID: 466 at
drivers/gpu/drm/i915/intel_display.c:9748
intel_check_page_flip+0xaa/0xf0 [i915]()
[    5.720349] WARN_ON(!in_interrupt())
[    5.720350] Modules linked in:
[    5.720376]  binfmt_misc rfcomm bnep arc4 eeepc_wmi hid_generic
asus_wmi sparse_keymap iwlmvm intel_powerclamp coretemp kvm_intel kvm
mac80211 crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel
aes_x86_64 lrw gf128mul dm_multipath glue_helper snd_hda_codec_hdmi
scsi_dh ablk_helper cryptd microcode btusb iwlwifi bluetooth serio_raw
cfg80211 i915 snd_hda_codec_realtek snd_hda_codec_generic lpc_ich
snd_hda_intel snd_hda_controller snd_hda_codec snd_hwdep snd_pcm
snd_seq_midi snd_seq_midi_event snd_rawmidi drm_kms_helper snd_seq drm
video snd_seq_device mac_hid snd_timer snd mei_me wmi mei shpchp
soundcore i2c_algo_bit usbhid hid parport_pc ppdev lp parport autofs4
btrfs xor raid6_pq psmouse dm_mirror r8169 ahci dm_region_hash libahci
mii dm_log
[    5.720379] CPU: 6 PID: 466 Comm: irq/32-i915 Not tainted 4.0.4-rt1+ #8
[    5.720380] Hardware name: System76, Inc. Wild Dog
Performance/H87-PLUS, BIOS 0705 12/05/2013
[    5.720382]  0000000000000009 ffff8803ea39bc98 ffffffff817c0694
0000000000000002
[    5.720383]  ffff8803ea39bce8 ffff8803ea39bcd8 ffffffff81073d8a
0000000000000001
[    5.720384]  ffff8803eb184000 ffff8800d7804800 0000000000000000
0000000000000000
[    5.720385] Call Trace:
[    5.720390]  [<ffffffff817c0694>] dump_stack+0x4f/0x90
[    5.720393]  [<ffffffff81073d8a>] warn_slowpath_common+0x8a/0xe0
[    5.720395]  [<ffffffff81073e26>] warn_slowpath_fmt+0x46/0x50
[    5.720410]  [<ffffffffa040bdba>] intel_check_page_flip+0xaa/0xf0 [i915]
[    5.720420]  [<ffffffffa03d7888>] ironlake_irq_handler+0x2e8/0x1000
[i915]
[    5.720423]  [<ffffffff813e7787>] ? debug_smp_processor_id+0x17/0x20
[    5.720424]  [<ffffffff81074512>] ? pin_current_cpu+0x92/0x1d0
[    5.720426]  [<ffffffff810d0690>] ? irq_thread_fn+0x50/0x50
[    5.720428]  [<ffffffff810d06b7>] irq_forced_thread_fn+0x27/0x80
[    5.720429]  [<ffffffff810d0c4f>] irq_thread+0x10f/0x160
[    5.720430]  [<ffffffff810d0740>] ? wake_threads_waitq+0x30/0x30
[    5.720432]  [<ffffffff810d0b40>] ? irq_thread_check_affinity+0x90/0x90
[    5.720433]  [<ffffffff81093d7b>] kthread+0xbb/0xe0
[    5.720434]  [<ffffffff81093cc0>] ? kthread_worker_fn+0x1a0/0x1a0
[    5.720436]  [<ffffffff817c6bd8>] ret_from_fork+0x58/0x90
[    5.720437]  [<ffffffff81093cc0>] ? kthread_worker_fn+0x1a0/0x1a0
[    5.720437] ---[ end trace 0000000000000002 ]---

There seem to be few past bug reports on this issue. Has this been
fixed? Should I be concerned about this?

thanks,
-- Shuah

-- 
Shuah Khan
Sr. Linux Kernel Developer
Open Source Innovation Group
Samsung Research America (Silicon Valley)
shuahkh@osg.samsung.com | (970) 217-8978