@kozak127

I get a kernel panic on the latest 3.13.0-32 kernel after compiling your code

Aug 10 02:02:15 flex2 kernel: [    3.467272] ------------[ cut here ]------------
Aug 10 02:02:15 flex2 kernel: [    3.468391] WARNING: CPU: 0 PID: 75 at /var/lib/dkms/i915-3.15-3.13/0.01/build/drivers/gpu/drm/i915/intel_pm.c:5715 i915_request_po
wer_well+0x39/0x40 [i915]()
Aug 10 02:02:15 flex2 kernel: [    3.469372] Modules linked in: x86_pkg_temp_thermal(+) intel_powerclamp coretemp snd_hda_intel(+) snd_hda_codec kvm_intel ip6table_
filter kvm snd_hwdep ip6_tables snd_pcm nf_conntrack_netbios_ns nf_conntrack_broadcast nf_nat_ftp nf_nat crct10dif_pclmul nf_conntrack_ftp crc32_pclmul snd_page_all
oc nf_conntrack ghash_clmulni_intel iptable_filter snd_seq_midi aesni_intel snd_seq_midi_event ip_tables cfg80211 aes_x86_64 x_tables snd_rawmidi lrw gf128mul glue_
helper snd_seq ablk_helper cryptd i915(OF) snd_seq_device snd_timer snd joydev drm_kms_helper(OF) serio_raw drm(OF) soundcore wmi mei_me ideapad_laptop i2c_algo_bit
 mei sparse_keymap lpc_ich mac_hid video psmouse ahci r8169 libahci mii
Aug 10 02:02:15 flex2 kernel: [    3.474794] CPU: 0 PID: 75 Comm: kworker/0:1 Tainted: GF          O 3.13.0-32-generic #57-Ubuntu
Aug 10 02:02:15 flex2 kernel: [    3.476444] Hardware name: LENOVO 20404/Lenovo Flex 2-14, BIOS A0CN21WW 03/21/2014
Aug 10 02:02:15 flex2 kernel: [    3.478441] Workqueue: events azx_probe_work [snd_hda_intel]
Aug 10 02:02:15 flex2 kernel: [    3.480340]  0000000000000009 ffff8801251abd58 ffffffff8171bcb4 0000000000000000
Aug 10 02:02:15 flex2 kernel: [    3.481424] snd_hda_intel 0000:00:1b.0: irq 60 for MSI/MSI-X
Aug 10 02:02:15 flex2 kernel: [    3.482254]  ffff8801251abd90 ffffffff810676cd ffff8801251e1d80 0000000000000000
Aug 10 02:02:15 flex2 kernel: [    3.483579]  0000000000000000 ffff880128d82000 ffff8800cad5e000 ffff8801251abda0
Aug 10 02:02:15 flex2 kernel: [    3.485647] Call Trace:
Aug 10 02:02:15 flex2 kernel: [    3.487569]  [<ffffffff8171bcb4>] dump_stack+0x45/0x56
Aug 10 02:02:15 flex2 kernel: [    3.489521]  [<ffffffff810676cd>] warn_slowpath_common+0x7d/0xa0
Aug 10 02:02:15 flex2 kernel: [    3.491136]  [<ffffffff810677aa>] warn_slowpath_null+0x1a/0x20
Aug 10 02:02:15 flex2 kernel: [    3.493198]  [<ffffffffa015dfc9>] i915_request_power_well+0x39/0x40 [i915]
Aug 10 02:02:15 flex2 kernel: [    3.495121]  [<ffffffffa03d6e42>] hda_display_power+0x32/0x40 [snd_hda_intel]
Aug 10 02:02:15 flex2 kernel: [    3.497040]  [<ffffffffa03d57b1>] azx_probe_continue+0x41/0x960 [snd_hda_intel]
Aug 10 02:02:15 flex2 kernel: [    3.498929]  [<ffffffff81097508>] ? finish_task_switch+0x128/0x170
Aug 10 02:02:15 flex2 kernel: [    3.500818]  [<ffffffffa03d6bd5>] azx_probe_work+0x15/0x20 [snd_hda_intel]
Aug 10 02:02:15 flex2 kernel: [    3.502669]  [<ffffffff810838f2>] process_one_work+0x182/0x450
Aug 10 02:02:15 flex2 kernel: [    3.503874]  [<ffffffff810846e1>] worker_thread+0x121/0x410
Aug 10 02:02:15 flex2 kernel: [    3.505455]  [<ffffffff810845c0>] ? rescuer_thread+0x430/0x430
Aug 10 02:02:15 flex2 kernel: [    3.506845]  [<ffffffff8108b3d2>] kthread+0xd2/0xf0
Aug 10 02:02:15 flex2 kernel: [    3.507958]  [<ffffffff8108b300>] ? kthread_create_on_node+0x1d0/0x1d0
Aug 10 02:02:15 flex2 kernel: [    3.509070]  [<ffffffff8172c5bc>] ret_from_fork+0x7c/0xb0
Aug 10 02:02:15 flex2 kernel: [    3.510127]  [<ffffffff8108b300>] ? kthread_create_on_node+0x1d0/0x1d0
Aug 10 02:02:15 flex2 kernel: [    3.511214] ---[ end trace 9cd095da83f39c2c ]---