Bluetooth crashing

[Duncan Bayne]

1) Linux Mint 18 'Sarah', Cinnamon, 64-bit. 4.4.0-21-generic #37-Ubuntu SMP Mon Apr 18 18:33:37 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux. Running on a Lenovo e550.

2) I powered on the machine, logged in, and started blueman-applet. I right-clicked on the blueman-applet icon and chose 'Devices...'.

3) blueman-applet reported that there were no adapters available. I had to restart my machine (hard reset) before I could use my bluetooth keyboard.

4) I expected there to be at least one Bluetooth adapter available.

5) The problem seems intermittent. A hard reset usually fixes the problem.

Looking at dmesg, I saw the following crash, which I think is the cause of the lack of reported adapters:

[ 49.299908] ------------[ cut here ]------------
[ 49.299942] WARNING: CPU: 3 PID: 1691 at /build/linux-Ay7j_C/linux-4.4.0/drivers/gpu/drm/i915/intel_uncore.c:619 hsw_unclaimed_reg_debug+0x69/0x90 [i915]()
[ 49.299944] Unclaimed register detected after reading register 0x22390
[ 49.299946] Modules linked in: hidp rfcomm bnep pci_stub vboxpci(OE) vboxnetadp(OE) vboxnetflt(OE) vboxdrv(OE) binfmt_misc drbg ansi_cprng intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp uvcvideo kvm_intel dm_crypt arc4 kvm btusb videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_core btrtl v4l2_common btbcm videodev btintel irqbypass crct10dif_pclmul bluetooth media crc32_pclmul aesni_intel aes_x86_64 iwlmvm lrw gf128mul glue_helper ablk_helper cryptd snd_seq_midi snd_seq_midi_event mac80211 snd_rawmidi snd_hda_codec_hdmi snd_hda_codec_conexant snd_seq snd_hda_codec_generic input_leds joydev serio_raw iwlwifi cfg80211 thinkpad_acpi snd_hda_intel snd_hda_codec rtsx_pci_ms snd_hda_core memstick snd_hwdep mei_me nvram mei snd_pcm intel_pch_thermal shpchp lpc_ich snd_seq_device snd_timer
[ 49.299998] snd soundcore mac_hid parport_pc ppdev lp parport autofs4 btrfs xor raid6_pq dm_mirror dm_region_hash dm_log hid_generic usbhid hid rtsx_pci_sdmmc i915 i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops psmouse e1000e drm ahci libahci ptp rtsx_pci pps_core wmi video fjes
[ 49.300022] CPU: 3 PID: 1691 Comm: Xorg Tainted: G W OE 4.4.0-21-generic #37-Ubuntu
[ 49.300024] Hardware name: LENOVO 20DFCTO1WW/20DFCTO1WW, BIOS J5ET46WW (1.17 ) 07/15/2015
[ 49.300026] 0000000000000086 0000000007d3d4ca ffff88045ecc3cd8 ffffffff813e93c3
[ 49.300029] ffff88045ecc3d20 ffffffffc02801c0 ffff88045ecc3d10 ffffffff81080f62
[ 49.300032] ffff880445650000 0000000000022390 0000000000000001 0000000000022390
[ 49.300035] Call Trace:
[ 49.300037] <IRQ> [<ffffffff813e93c3>] dump_stack+0x63/0x90
[ 49.300046] [<ffffffff81080f62>] warn_slowpath_common+0x82/0xc0
[ 49.300049] [<ffffffff81080ffc>] warn_slowpath_fmt+0x5c/0x80
[ 49.300075] [<ffffffffc01f8379>] hsw_unclaimed_reg_debug+0x69/0x90 [i915]
[ 49.300097] [<ffffffffc01fb001>] gen6_read32+0xd1/0x1a0 [i915]
[ 49.300121] [<ffffffffc01ee568>] intel_lrc_irq_handler+0xc8/0x240 [i915]
[ 49.300141] [<ffffffffc01aadc7>] gen8_gt_irq_handler+0x217/0x240 [i915]
[ 49.300161] [<ffffffffc01aae91>] gen8_irq_handler+0xa1/0x740 [i915]
[ 49.300165] [<ffffffff810da8ed>] handle_irq_event_percpu+0x8d/0x1d0
[ 49.300168] [<ffffffff810daa6e>] handle_irq_event+0x3e/0x60
[ 49.300171] [<ffffffff810ddfad>] handle_edge_irq+0x7d/0x150
[ 49.300174] [<ffffffff8103115a>] handle_irq+0x1a/0x30
[ 49.300178] [<ffffffff81826edb>] do_IRQ+0x4b/0xd0
[ 49.300181] [<ffffffff81824fc2>] common_interrupt+0x82/0x82
[ 49.300183] <EOI> [<ffffffffc02245e0>] ? intel_crtc_mode_get+0x290/0x290 [i915]
[ 49.300232] [<ffffffffc01dc58a>] ? __i915_add_request+0x12a/0x210 [i915]
[ 49.300255] [<ffffffffc01d0b76>] i915_gem_execbuffer_retire_commands+0x26/0x30 [i915]
[ 49.300278] [<ffffffffc01ef72b>] intel_execlists_submission+0x2eb/0x410 [i915]
[ 49.300301] [<ffffffffc01d0500>] i915_gem_do_execbuffer.isra.25+0xfa0/0x12a0 [i915]
[ 49.300323] [<ffffffffc01d1482>] i915_gem_execbuffer2+0xb2/0x240 [i915]
[ 49.300345] [<ffffffffc01de022>] ? i915_gem_busy_ioctl+0x92/0xe0 [i915]
[ 49.300362] [<ffffffffc0080712>] drm_ioctl+0x152/0x540 [drm]
[ 49.300383] [<ffffffffc01d13d0>] ? i915_gem_execbuffer+0x310/0x310 [i915]
[ 49.300387] [<ffffffff812200ff>] do_vfs_ioctl+0x29f/0x490
[ 49.300390] [<ffffffff81220369>] SyS_ioctl+0x79/0x90
[ 49.300394] [<ffffffff818244f2>] entry_SYSCALL_64_fastpath+0x16/0x71
[ 49.300396] ---[ end trace 7f5f1163cf30d40f ]---

I'm a developer, and happy to help debug this problem, and / or test patches.