Hi, I just noticed this starting to happen - I can't see any sign of it in syslog before I rebuilt the modules (git commit tags are listed below). I don't know if this is a backporting issue or a bug in mainline. The system in question has two dual-tuner cards, one a USB (mounted on a PCI card) the other a PCI card. Both use the cx23885 driver. As far as I can see the PCI card is where the problem lies - there's no way to distinguish between the two tuners (I found this when trying to write some udev rules to generate stably-named symlinks). % uname -a Linux ubuntu 2.6.32-27-generic #49-Ubuntu SMP Wed Dec 1 23:52:12 UTC 2010 i686 GNU/Linux [ 4.020062] Latest git patches (needed if you report a bug to linux-media@xxxxxxxxxxxxxxx): [ 4.020063] 5e094096b93c9c48b4b90457e83cbca6fc2ff5d4 [media] v1.88 DM04/QQBOX Move remote to use rc_core dvb-usb-remote [ 4.020064] 154d70a479c27695a4ad938cc0b14cb91866cf2d [media] Add missing include guard to header file [ 4.020065] 537d9c461e6cbe7a2cc35121f0ee4d48f52753a3 [media] Inlined functions should be static The error I see is: [ 34.900554] ------------[ cut here ]------------ [ 34.900561] WARNING: at /build/buildd/linux-2.6.32/fs/sysfs/dir.c:491 sysfs_add_one+0xa0/0x100() [ 34.900563] Hardware name: [ 34.900565] sysfs: cannot create duplicate filename '/devices/pci0000:00/0000:00:1c.3/0000:04:00.0/firmware/0000:04:00.0' [ 34.900567] Modules linked in: ppdev ipt_MASQUERADE iptable_nat nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_state nf_conntrack ipt_REJECT xt_tcpudp iptable_filter ip_tables x_tables bridge stp kvm_intel kvm snd_hda_codec_realtek snd_hda_intel snd_hda_codec snd_hwdep snd_pcm_oss fbcon snd_mixer_oss tileblit font snd_pcm snd_seq_dummy bitblit ir_kbd_i2c tuner_xc2028 softcursor snd_seq_oss vga16fb snd_seq_midi arc4 vgastate ir_lirc_codec lirc_dev rc_imon_mce zl10353 snd_rawmidi ir_sony_decoder cx23885 lp i915 snd_seq_midi_event ir_jvc_decoder ir_rc6_decoder ir_rc5_decoder dvb_usb_cxusb snd_seq parport cx2341x drm_kms_helper intel_agp videobuf_dma_sg videobuf_dvb videobuf_core snd_timer snd_seq_device drm i2c_algo_bit video ir_nec_decoder output v4l2_common snd rtl8180 dib7000p dibx000_common soundcore agpgart snd_page_alloc videodev mac80211 eeprom_93cx6 dvb_usb btcx_risc imon psmouse dvb_core cfg80211 rc_core tveeprom serio_raw dib0070 usb_storage raid10 raid456 async_raid6_recov async_pq raid6_pq async_xor xor async_memcpy async_tx raid1 raid0 ohci1394 multipath ieee1394 ahci e1000e pata_marvell linear [ 34.900653] Pid: 2399, comm: kdvb-ad-2-fe-0 Not tainted 2.6.32-27-generic #49-Ubuntu [ 34.900655] Call Trace: [ 34.900660] [<c014c802>] warn_slowpath_common+0x72/0xa0 [ 34.900663] [<c02609e0>] ? sysfs_add_one+0xa0/0x100 [ 34.900666] [<c02609e0>] ? sysfs_add_one+0xa0/0x100 [ 34.900669] [<c014c87b>] warn_slowpath_fmt+0x2b/0x30 [ 34.900672] [<c02609e0>] sysfs_add_one+0xa0/0x100 [ 34.900675] [<c0260a8e>] create_dir+0x4e/0x90 [ 34.900678] [<c0260b00>] sysfs_create_dir+0x30/0x50 [ 34.900682] [<c034d642>] kobject_add_internal+0x92/0x1d0 [ 34.900684] [<c0353846>] ? vsnprintf+0x206/0x410 [ 34.900687] [<c034d86d>] kobject_add_varg+0x2d/0x50 [ 34.900692] [<c03e4aeb>] ? get_device_parent+0xcb/0x1a0 [ 34.900695] [<c034d8ec>] kobject_add+0x2c/0x60 [ 34.900698] [<c03e5c69>] device_add+0x99/0x430 [ 34.900701] [<c03ed8d0>] ? pm_runtime_init+0xb0/0xc0 [ 34.900704] [<c03e6017>] device_register+0x17/0x20 [ 34.900707] [<c03f098b>] fw_register_device+0x14b/0x210 [ 34.900710] [<c03f0a7d>] fw_setup_device+0x2d/0x100 [ 34.900713] [<c03f0c00>] _request_firmware+0xb0/0x220 [ 34.900715] [<c03f0e17>] request_firmware+0x17/0x20 [ 34.900722] [<f862317c>] generic_set_freq+0x99c/0x18f0 [tuner_xc2028] [ 34.900725] [<c0353daa>] ? delay_tsc+0x2a/0x70 [ 34.900727] [<c0353d71>] ? __const_udelay+0x31/0x40 [ 34.900735] [<f858e549>] ? i2c_sendbytes+0x169/0x3c0 [cx23885] [ 34.900742] [<f858e810>] ? i2c_xfer+0x70/0x140 [cx23885] [ 34.900745] [<c058bde2>] ? _cond_resched+0x32/0x50 [ 34.900749] [<c0474804>] ? i2c_transfer+0x94/0xc0 [ 34.900753] [<f8624475>] xc2028_set_params+0x195/0x286 [tuner_xc2028] [ 34.900757] [<f83e5c4c>] zl10353_set_parameters+0x4ec/0x630 [zl10353] [ 34.900763] [<c058d9bf>] ? _spin_lock_irqsave+0x2f/0x50 [ 34.900766] [<c015b2ac>] ? lock_timer_base+0x2c/0x60 [ 34.900777] [<f82b71d5>] dvb_frontend_swzigzag_autotune+0x115/0x300 [dvb_core] [ 34.900785] [<f82b81d1>] dvb_frontend_swzigzag+0x261/0x300 [dvb_core] [ 34.900792] [<f82b8a67>] dvb_frontend_thread+0x3c7/0x700 [dvb_core] [ 34.900795] [<c058b8ec>] ? schedule+0x44c/0x840 [ 34.900799] [<c0167b50>] ? autoremove_wake_function+0x0/0x50 [ 34.900807] [<f82b86a0>] ? dvb_frontend_thread+0x0/0x700 [dvb_core] [ 34.900810] [<c01678c4>] kthread+0x74/0x80 [ 34.900813] [<c0167850>] ? kthread+0x0/0x80 [ 34.900817] [<c0104087>] kernel_thread_helper+0x7/0x10 [ 34.900819] ---[ end trace 14130c4e15fe09fe ]--- [ 34.900822] kobject_add_internal failed for 0000:04:00.0 with -EEXIST, don't try to register things with the same name in the same directory. [ 34.900826] Pid: 2399, comm: kdvb-ad-2-fe-0 Tainted: G W 2.6.32-27-ge neric #49-Ubuntu [ 34.900828] Call Trace: [ 34.900830] [<c058b313>] ? printk+0x1d/0x22 [ 34.900833] [<c034d6ec>] kobject_add_internal+0x13c/0x1d0 [ 34.900836] [<c034d86d>] kobject_add_varg+0x2d/0x50 [ 34.900839] [<c03e4aeb>] ? get_device_parent+0xcb/0x1a0 [ 34.900842] [<c034d8ec>] kobject_add+0x2c/0x60 [ 34.900845] [<c03e5c69>] device_add+0x99/0x430 [ 34.900848] [<c03ed8d0>] ? pm_runtime_init+0xb0/0xc0 [ 34.900851] [<c03e6017>] device_register+0x17/0x20 [ 34.900854] [<c03f098b>] fw_register_device+0x14b/0x210 [ 34.900857] [<c03f0a7d>] fw_setup_device+0x2d/0x100 [ 34.900859] [<c03f0c00>] _request_firmware+0xb0/0x220 [ 34.900867] [<f862317c>] generic_set_freq+0x99c/0x18f0 [tuner_xc2028] [ 34.900870] [<c0353daa>] ? delay_tsc+0x2a/0x70 [ 34.900873] [<c0353d71>] ? __const_udelay+0x31/0x40 [ 34.900880] [<f858e549>] ? i2c_sendbytes+0x169/0x3c0 [cx23885] [ 34.900889] [<f858e810>] ? i2c_xfer+0x70/0x140 [cx23885] [ 34.900892] [<c058bde2>] ? _cond_resched+0x32/0x50 [ 34.900895] [<c0474804>] ? i2c_transfer+0x94/0xc0 [ 34.900899] [<f8624475>] xc2028_set_params+0x195/0x286 [tuner_xc2028] [ 34.900902] [<f83e5c4c>] zl10353_set_parameters+0x4ec/0x630 [zl10353] [ 34.900905] [<c058d9bf>] ? _spin_lock_irqsave+0x2f/0x50 [ 34.900908] [<c015b2ac>] ? lock_timer_base+0x2c/0x60 [ 34.900916] [<f82b71d5>] dvb_frontend_swzigzag_autotune+0x115/0x300 [dvb_core] [ 34.900924] [<f82b81d1>] dvb_frontend_swzigzag+0x261/0x300 [dvb_core] [ 34.900931] [<f82b8a67>] dvb_frontend_thread+0x3c7/0x700 [dvb_core] [ 34.900934] [<c058b8ec>] ? schedule+0x44c/0x840 [ 34.900937] [<c0167b50>] ? autoremove_wake_function+0x0/0x50 [ 34.900945] [<f82b86a0>] ? dvb_frontend_thread+0x0/0x700 [dvb_core] [ 34.900948] [<c01678c4>] kthread+0x74/0x80 [ 34.900951] [<c0167850>] ? kthread+0x0/0x80 [ 34.900954] [<c0104087>] kernel_thread_helper+0x7/0x10 [ 34.900954] [<c0104087>] kernel_thread_helper+0x7/0x10 [ 34.900956] cx23885 0000:04:00.0: fw_register_device: device_register failed [ 34.900965] BUG: unable to handle kernel NULL pointer dereference at 00000040 [ 34.900968] IP: [<c03eff62>] fw_dev_release+0x12/0x60 [ 34.900971] *pde = 7c87e067 [ 34.900974] Oops: 0000 [#1] SMP [ 34.900976] last sysfs file: /sys/devices/pci0000:00/0000:00:1f.2/host2/target2:0:0/2:0:0:0/block/sda/size [ 34.900979] Modules linked in: ppdev ipt_MASQUERADE iptable_nat nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_state nf_conntrack ipt_REJECT xt_tcpudp iptable_filter ip_tables x_tables bridge stp kvm_intel kvm snd_hda_codec_realtek snd_hda_intel snd_hda_codec snd_hwdep snd_pcm_oss fbcon snd_mixer_oss tileblit font snd_pcm snd_seq_dummy bitblit ir_kbd_i2c tuner_xc2028 softcursor snd_seq_oss vga16fb snd_seq_midi arc4 vgastate ir_lirc_codec lirc_dev rc_imon_mce zl10353 snd_rawmidi ir_sony_decoder cx23885 lp i915 snd_seq_midi_event ir_jvc_decoder ir_rc6_decoder ir_rc5_decoder dvb_usb_cxusb snd_seq parport cx2341x drm_kms_helper intel_agp videobuf_dma_sg videobuf_dvb videobuf_core snd_timer snd_seq_device drm i2c_algo_bit video ir_nec_decoder output v4l2_common snd rtl8180 dib7000p dibx000_common soundcore agpgart snd_page_alloc videodev mac80211 eeprom_93cx6 dvb_usb btcx_risc imon psmouse dvb_core cfg80211 rc_core tveeprom serio_raw dib0070 usb_storage raid10 raid456 async_raid6_recov async_pq raid6_pq async_xor xor async_memcpy async_tx raid1 raid0 ohci1394 multipath ieee1394 ahci e1000e pata_marvell linear [ 34.901053] [ 34.901055] Pid: 2399, comm: kdvb-ad-2-fe-0 Tainted: G W (2.6.32-27-generic #49-Ubuntu) [ 34.901058] EIP: 0060:[<c03eff62>] EFLAGS: 00010246 CPU: 0 [ 34.901060] EIP is at fw_dev_release+0x12/0x60 [ 34.901062] EAX: 00000000 EBX: 00000000 ECX: ffffe688 EDX: c03eff50 [ 34.901064] ESI: c078a2a0 EDI: f396d200 EBP: f39dbc84 ESP: f39dbc78 [ 34.901066] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 [ 34.901069] Process kdvb-ad-2-fe-0 (pid: 2399, ti=f39da000 task=f39bbfc0 task.ti=f39da000) [ 34.901070] Stack: [ 34.901072] 00000000 c078a2a0 f5c8c330 f39dbca0 c03e500e 00000033 0000000f 00000000 [ 34.901077] <0> 205bbca0 f396d208 f39dbcb4 c034d4da f396d224 c034d4a0 f7184858 f39dbcc4 [ 34.901084] <0> c034e36d ffffffef f396d200 f39dbce4 c034d3cd 8f7bda99 ffffffef f396d200 [ 34.901091] Call Trace: [ 34.901094] [<c03e500e>] ? device_release+0x1e/0x80 [ 34.901097] [<c034d4da>] ? kobject_release+0x3a/0x80 [ 34.901100] [<c034d4a0>] ? kobject_release+0x0/0x80 [ 34.901103] [<c034e36d>] ? kref_put+0x2d/0x60 [ 34.901106] [<c034d3cd>] ? kobject_put+0x1d/0x50 [ 34.901108] [<c058b313>] ? printk+0x1d/0x22 [ 34.901111] [<c03e4924>] ? put_device+0x14/0x20 [ 34.901114] [<c03f0a14>] ? fw_register_device+0x1d4/0x210 [ 34.901119] [<c03f0a7d>] ? fw_setup_device+0x2d/0x100 [ 34.901122] [<c03f0c00>] ? _request_firmware+0xb0/0x220 [ 34.901125] [<c03f0e17>] ? request_firmware+0x17/0x20 [ 34.901129] [<f862317c>] ? generic_set_freq+0x99c/0x18f0 [tuner_xc2028] [ 34.901131] [<c0353daa>] ? delay_tsc+0x2a/0x70 [ 34.901134] [<c0353d71>] ? __const_udelay+0x31/0x40 [ 34.901141] [<f858e549>] ? i2c_sendbytes+0x169/0x3c0 [cx23885] [ 34.901147] [<f858e810>] ? i2c_xfer+0x70/0x140 [cx23885] [ 34.901150] [<c058bde2>] ? _cond_resched+0x32/0x50 [ 34.901154] [<c0474804>] ? i2c_transfer+0x94/0xc0 [ 34.901158] [<f8624475>] ? xc2028_set_params+0x195/0x286 [tuner_xc2028] [ 34.901162] [<f83e5c4c>] ? zl10353_set_parameters+0x4ec/0x630 [zl10353] [ 34.901165] [<c058d9bf>] ? _spin_lock_irqsave+0x2f/0x50 [ 34.901167] [<c015b2ac>] ? lock_timer_base+0x2c/0x60 [ 34.901175] [<f82b71d5>] ? dvb_frontend_swzigzag_autotune+0x115/0x300 [dvb_core] [ 34.901183] [<f82b81d1>] ? dvb_frontend_swzigzag+0x261/0x300 [dvb_core] [ 34.901190] [<f82b8a67>] ? dvb_frontend_thread+0x3c7/0x700 [dvb_core] [ 34.901193] [<c058b8ec>] ? schedule+0x44c/0x840 [ 34.901196] [<c0167b50>] ? autoremove_wake_function+0x0/0x50 [ 34.901205] [<f82b86a0>] ? dvb_frontend_thread+0x0/0x700 [dvb_core] [ 34.901208] [<c01678c4>] ? kthread+0x74/0x80 [ 34.901210] [<c0167850>] ? kthread+0x0/0x80 [ 34.901214] [<c0104087>] ? kernel_thread_helper+0x7/0x10 [ 34.901215] Code: 08 e8 13 3b f6 ff 83 c4 0c 5b 5d c3 8d b6 00 00 00 00 8d bc 27 00 00 00 00 55 89 e5 57 56 53 0f 1f 44 00 00 89 c7 e8 5e 7f ff ff <8b> 58 40 89 c6 85 db 7e 1a 31 db 8d 76 00 8b 46 3c 31 d2 8b 04 [ 34.901251] EIP: [<c03eff62>] fw_dev_release+0x12/0x60 SS:ESP 0068:f39dbc78 [ 34.901255] CR2: 0000000000000040 [ 34.901261] ---[ end trace 14130c4e15fe09ff ]--- % dmesg |grep -i cx23885 # up to the point where excerpt above appears: [ 5.222141] cx23885 driver version 0.0.2 loaded [ 5.222178] cx23885 0000:04:00.0: PCI INT A -> GSI 19 (level, low) -> IRQ 19 [ 5.222243] CORE cx23885[0]: subsystem: 18ac:db78, board: DViCO FusionHDTV DVB-T Dual Express [card=11,autodetected] [ 5.476509] cx23885_dvb_register() allocating 1 frontend(s) [ 5.476512] cx23885[0]: cx23885 based dvb card [ 5.477126] DVB: registering new adapter (cx23885[0]) [ 5.477381] cx23885_dvb_register() allocating 1 frontend(s) [ 5.477383] cx23885[0]: cx23885 based dvb card [ 5.477988] DVB: registering new adapter (cx23885[0]) [ 5.478551] cx23885_dev_checkrevision() Hardware revision = 0xb0 [ 5.478557] cx23885[0]/0: found at 0000:04:00.0, rev: 2, irq: 19, latency: 0, mmio: 0x90000000 [ 5.478564] cx23885 0000:04:00.0: setting latency timer to 64 [ 5.478646] cx23885 0000:04:00.0: irq 32 for MSI/MSI-X [ 5.556503] cxusb: No IR receiver detected on this device. [ 5.557278] usbcore: registered new interface driver dvb_usb_cxusb [ 34.888152] cx23885 0000:04:00.0: firmware: requesting xc3028-v27.fw [ 34.900542] cx23885 0000:04:00.0: firmware: requesting xc3028-v27.fw Hardware details % lsusb | grep -i dvico Bus 003 Device 003: ID 0fe9:db78 DVICO FusionHDTV DVB-T Dual Digital 4 (ZL10353+xc2028/xc3028) (initialized) Bus 003 Device 002: ID 0fe9:db78 DVICO FusionHDTV DVB-T Dual Digital 4 (ZL10353+xc2028/xc3028) (initialized) % lspci |grep -i cx 04:00.0 Multimedia video controller: Conexant Systems, Inc. CX23885 PCI Video and Audio Decoder (rev 02) % lspci -vvn -s 04:00 04:00.0 0400: 14f1:8852 (rev 02) Subsystem: 18ac:db78 Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+ Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0, Cache Line Size: 64 bytes Interrupt: pin A routed to IRQ 32 Region 0: Memory at 90000000 (64-bit, non-prefetchable) [size=2M] Capabilities: [40] Express (v1) Endpoint, MSI 00 DevCap: MaxPayload 128 bytes, PhantFunc 0, Latency L0s <64ns, L1 <1us ExtTag- AttnBtn- AttnInd- PwrInd- RBE- FLReset- DevCtl: Report errors: Correctable- Non-Fatal- Fatal- Unsupported- RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+ MaxPayload 128 bytes, MaxReadReq 512 bytes DevSta: CorrErr- UncorrErr- FatalErr- UnsuppReq- AuxPwr- TransPend- LnkCap: Port #0, Speed 2.5GT/s, Width x1, ASPM L0s L1, Latency L0 <2us, L1 <4us ClockPM- Suprise- LLActRep- BwNot- LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- Retrain- CommClk+ ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt- LnkSta: Speed 2.5GT/s, Width x1, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt- Capabilities: [80] Power Management version 2 Flags: PMEClk- DSI+ D1+ D2+ AuxCurrent=0mA PME(D0+,D1+,D2+,D3hot+,D3cold-) Status: D0 PME-Enable- DSel=0 DScale=0 PME- Capabilities: [90] Vital Product Data <?> Capabilities: [a0] Message Signalled Interrupts: Mask- 64bit+ Queue=0/0 Enable+ Address: 00000000fee0200c Data: 41c9 Capabilities: [100] Advanced Error Reporting <?> Capabilities: [200] Virtual Channel <?> Kernel driver in use: cx23885 Kernel modules: cx23885 Regards Vince -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html