more diagnostics: when I open the bluetooth system preferences, it first takes a long time until the preferences come up (saying "starting bluetooth" in the application panel). once the preferences appear, it says "bluetooth is disabled". when I click on "enable bluetooth", I get this stack trace in the kernel log: Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756719] WARNING: at /build/buildd/linux-2.6.35/fs/sysfs/dir.c:451 sysfs_add_one+0xc5/0x130() Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756723] Hardware name: Latitude E6410 Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756726] sysfs: cannot create duplicate filename '/class/bluetooth/hci0:11' Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756729] Modules linked in: hidp iptable_filter ip_tables x_tables binfmt_misc rfcomm sco bnep l2cap vboxnetadp vboxnetflt vboxdrv snd_hda_codec_nvhdmi joydev usbhid arc4 snd_hda_codec_idt snd_seq_midi snd_rawmidi iwlagn snd_seq_midi_event hid snd_seq snd_hda_intel nvidia(P) snd_seq_device snd_hda_codec iwlcore snd_hwdep mac80211 snd_pcm uvcvideo btusb ppdev cfg80211 snd_timer bluetooth dcdbas videodev v4l1_compat v4l2_compat_ioctl32 dell_wmi snd psmouse soundcore serio_raw intel_agp snd_page_alloc parport_pc intel_ips video output lp parport sdhci_pci sdhci firewire_ohci ahci led_class e1000e firewire_core libahci crc_itu_t Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756805] Pid: 2903, comm: hci0 Tainted: P D W 2.6.35-22-generic #35-Ubuntu Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756808] Call Trace: Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756872] [] warn_slowpath_common+0x7f/0xc0 Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756877] [] warn_slowpath_fmt+0x46/0x50 Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756883] [] sysfs_add_one+0xc5/0x130 Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756888] [] sysfs_do_create_link+0x13b/0x210 Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756894] [] sysfs_create_link+0x13/0x20 Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756903] [] device_add_class_symlinks+0x6c/0x100 Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756908] [] ? sysfs_create_file+0x26/0x30 Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756914] [] device_add+0x238/0x440 Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756919] [] ? device_private_init+0x71/0x80 Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756932] [] add_conn+0x5b/0xe0 [bluetooth] Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756941] [] ? add_conn+0x0/0xe0 [bluetooth] Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756949] [] run_workqueue+0xc5/0x1a0 Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756955] [] worker_thread+0xa3/0x110 Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756961] [] ? autoremove_wake_function+0x0/0x40 Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756966] [] ? worker_thread+0x0/0x110 Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756971] [] kthread+0x96/0xa0 Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756978] [] kernel_thread_helper+0x4/0x10 Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756983] [] ? kthread+0x0/0xa0 Oct 21 09:30:32 cemmnbk80 kernel: [ 2138.756988] [] ? kernel_thread_helper+0x0/0x10