I just noticed that timing matters. If I bring the USB devices up one at a time, with lots of time between power ups, things seem to initialize better. And there are two ports that won't work much at all and two that work until this failure occurs. I was able to reproduce the HCI shut down with kernel 3.5.2 I believe this dmesg shows the six devices activating, then my code streams from them, then bad things happen when I attempt to stop streaming. [ 6912.680118] usb 2-5: new SuperSpeed USB device number 83 using xhci_hcd [ 6912.703071] usb 2-5: New USB device found, idVendor=05e3, idProduct=0616 [ 6912.703074] usb 2-5: New USB device strings: Mfr=1, Product=2, SerialNumber=0 [ 6912.703075] usb 2-5: Product: USB3.0 Hub [ 6912.703076] usb 2-5: Manufacturer: GenesysLogic [ 6912.705450] hub 2-5:1.0: USB hub found [ 6912.705793] hub 2-5:1.0: 4 ports detected [ 6912.711272] usb 2-5: Set SEL for device-initiated U1 failed. [ 6917.709657] usb 2-5: Set SEL for device-initiated U2 failed. [ 6917.889626] usb 2-5: USB disconnect, device number 83 [ 6918.709590] hub 2-5:1.0: activate --> -19 [ 6918.989734] usb 2-5: new SuperSpeed USB device number 84 using xhci_hcd [ 6919.012688] usb 2-5: New USB device found, idVendor=05e3, idProduct=0616 [ 6919.012691] usb 2-5: New USB device strings: Mfr=1, Product=2, SerialNumber=0 [ 6919.012692] usb 2-5: Product: USB3.0 Hub [ 6919.012693] usb 2-5: Manufacturer: GenesysLogic [ 6919.015215] hub 2-5:1.0: USB hub found [ 6919.015568] hub 2-5:1.0: 4 ports detected [ 6919.289584] usb 2-5.2: new SuperSpeed USB device number 85 using xhci_hcd [ 6919.310095] usb 2-5.2: LPM exit latency is zeroed, disabling LPM. [ 6919.310912] usb 2-5.2: New USB device found, idVendor=2560, idProduct=c112 [ 6919.310914] usb 2-5.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 6919.310916] usb 2-5.2: Product: See3CAM_11CUG [ 6919.310917] usb 2-5.2: Manufacturer: e-con Systems [ 6919.310918] usb 2-5.2: SerialNumber: 29239400 [ 6919.311802] uvcvideo: Found UVC 1.00 device See3CAM_11CUG (2560:c112) [ 6919.312900] input: See3CAM_11CUG as /devices/pci0000:00/0000:00:14.0/usb2/2-5/2-5.2/2-5.2:1.0/input/input76 [ 6920.289836] hid-generic 0003:2560:C112.004C: hiddev0,hidraw6: USB HID v1.11 Device [e-con Systems See3CAM_11CUG] on usb-0000:00:14.0-5.2/input2 [ 6920.369500] usb 2-5.3: new SuperSpeed USB device number 86 using xhci_hcd [ 6920.390080] usb 2-5.3: LPM exit latency is zeroed, disabling LPM. [ 6920.390802] usb 2-5.3: New USB device found, idVendor=2560, idProduct=c112 [ 6920.390804] usb 2-5.3: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 6920.390805] usb 2-5.3: Product: See3CAM_11CUG [ 6920.390806] usb 2-5.3: Manufacturer: e-con Systems [ 6920.390807] usb 2-5.3: SerialNumber: 22239400 [ 6920.391738] uvcvideo: Found UVC 1.00 device See3CAM_11CUG (2560:c112) [ 6920.392976] input: See3CAM_11CUG as /devices/pci0000:00/0000:00:14.0/usb2/2-5/2-5.3/2-5.3:1.0/input/input77 [ 6921.369593] hid-generic 0003:2560:C112.004D: hiddev0,hidraw7: USB HID v1.11 Device [e-con Systems See3CAM_11CUG] on usb-0000:00:14.0-5.3/input2 [ 6921.449426] usb 2-5.4: new SuperSpeed USB device number 87 using xhci_hcd [ 6921.470027] usb 2-5.4: LPM exit latency is zeroed, disabling LPM. [ 6921.470751] usb 2-5.4: New USB device found, idVendor=2560, idProduct=c112 [ 6921.470753] usb 2-5.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 6921.470754] usb 2-5.4: Product: See3CAM_11CUG [ 6921.470755] usb 2-5.4: Manufacturer: e-con Systems [ 6921.470756] usb 2-5.4: SerialNumber: 21155500 [ 6921.471731] uvcvideo: Found UVC 1.00 device See3CAM_11CUG (2560:c112) [ 6921.472963] input: See3CAM_11CUG as /devices/pci0000:00/0000:00:14.0/usb2/2-5/2-5.4/2-5.4:1.0/input/input78 [ 6922.449562] hid-generic 0003:2560:C112.004E: hiddev0,hidraw8: USB HID v1.11 Device [e-con Systems See3CAM_11CUG] on usb-0000:00:14.0-5.4/input2 [ 6926.793508] usb 1-3: USB disconnect, device number 81 [ 6926.894974] usb 2-5: USB disconnect, device number 84 [ 6926.894977] usb 2-5.2: USB disconnect, device number 85 [ 6927.019976] usb 2-5.3: USB disconnect, device number 86 [ 6927.159916] usb 2-5.4: USB disconnect, device number 87 [ 6950.137405] usb 1-3: new high-speed USB device number 90 using xhci_hcd [ 6950.177595] usb 2-5: new SuperSpeed USB device number 88 using xhci_hcd [ 6950.200650] usb 2-5: New USB device found, idVendor=05e3, idProduct=0616 [ 6950.200653] usb 2-5: New USB device strings: Mfr=1, Product=2, SerialNumber=0 [ 6950.200654] usb 2-5: Product: USB3.0 Hub [ 6950.200655] usb 2-5: Manufacturer: GenesysLogic [ 6950.203428] hub 2-5:1.0: USB hub found [ 6950.203764] hub 2-5:1.0: 4 ports detected [ 6950.285412] usb 1-3: New USB device found, idVendor=05e3, idProduct=0610 [ 6950.285415] usb 1-3: New USB device strings: Mfr=1, Product=2, SerialNumber=0 [ 6950.285416] usb 1-3: Product: USB2.0 Hub [ 6950.285417] usb 1-3: Manufacturer: GenesysLogic [ 6950.286337] hub 1-3:1.0: USB hub found [ 6950.287310] hub 1-3:1.0: 4 ports detected [ 6964.416472] usb 2-5.4: new SuperSpeed USB device number 89 using xhci_hcd [ 6964.437048] usb 2-5.4: LPM exit latency is zeroed, disabling LPM. [ 6964.437845] usb 2-5.4: New USB device found, idVendor=2560, idProduct=c112 [ 6964.437847] usb 2-5.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 6964.437849] usb 2-5.4: Product: See3CAM_11CUG [ 6964.437850] usb 2-5.4: Manufacturer: e-con Systems [ 6964.437851] usb 2-5.4: SerialNumber: 21155500 [ 6964.438751] uvcvideo: Found UVC 1.00 device See3CAM_11CUG (2560:c112) [ 6964.439982] input: See3CAM_11CUG as /devices/pci0000:00/0000:00:14.0/usb2/2-5/2-5.4/2-5.4:1.0/input/input79 [ 6965.416570] hid-generic 0003:2560:C112.004F: hiddev0,hidraw6: USB HID v1.11 Device [e-con Systems See3CAM_11CUG] on usb-0000:00:14.0-5.4/input2 [ 6980.505382] usb 2-5.3: new SuperSpeed USB device number 90 using xhci_hcd [ 6980.525970] usb 2-5.3: LPM exit latency is zeroed, disabling LPM. [ 6980.526757] usb 2-5.3: New USB device found, idVendor=2560, idProduct=c112 [ 6980.526760] usb 2-5.3: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 6980.526762] usb 2-5.3: Product: See3CAM_11CUG [ 6980.526763] usb 2-5.3: Manufacturer: e-con Systems [ 6980.526764] usb 2-5.3: SerialNumber: 22239400 [ 6980.527694] uvcvideo: Found UVC 1.00 device See3CAM_11CUG (2560:c112) [ 6980.528872] input: See3CAM_11CUG as /devices/pci0000:00/0000:00:14.0/usb2/2-5/2-5.3/2-5.3:1.0/input/input80 [ 6981.505961] hid-generic 0003:2560:C112.0050: hiddev0,hidraw7: USB HID v1.11 Device [e-con Systems See3CAM_11CUG] on usb-0000:00:14.0-5.3/input2 [ 6991.704636] usb 2-5.2: new SuperSpeed USB device number 91 using xhci_hcd [ 6991.725247] usb 2-5.2: LPM exit latency is zeroed, disabling LPM. [ 6991.725965] usb 2-5.2: New USB device found, idVendor=2560, idProduct=c112 [ 6991.725967] usb 2-5.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 6991.725968] usb 2-5.2: Product: See3CAM_11CUG [ 6991.725969] usb 2-5.2: Manufacturer: e-con Systems [ 6991.725970] usb 2-5.2: SerialNumber: 29239400 [ 6991.726819] uvcvideo: Found UVC 1.00 device See3CAM_11CUG (2560:c112) [ 6991.728340] input: See3CAM_11CUG as /devices/pci0000:00/0000:00:14.0/usb2/2-5/2-5.2/2-5.2:1.0/input/input81 [ 6992.705261] hid-generic 0003:2560:C112.0051: hiddev0,hidraw8: USB HID v1.11 Device [e-con Systems See3CAM_11CUG] on usb-0000:00:14.0-5.2/input2 [ 7020.300785] uvcvideo: Non-zero status (-71) in video completion handler. [ 7030.260132] uvcvideo: Non-zero status (-71) in video completion handler. [ 7039.349763] uvcvideo: Non-zero status (-71) in video completion handler. [ 7047.660804] uvcvideo: Failed to query (GET_CUR) UVC control 2 on unit 2: -110 (exp. 2). [ 7056.198657] uvcvideo: Non-zero status (-71) in video completion handler. [ 7087.808760] uvcvideo: Failed to resubmit video URB (-1). [ 7088.086522] uvcvideo: Non-zero status (-71) in video completion handler. [ 7095.985002] uvcvideo: Non-zero status (-71) in video completion handler. [ 7106.546786] uvcvideo: Failed to query (GET_CUR) UVC control 2 on unit 2: -110 (exp. 2). [ 7115.956120] uvcvideo: Failed to query (GET_CUR) UVC control 2 on unit 2: -110 (exp. 2). [ 7179.430196] uvcvideo: Non-zero status (-71) in video completion handler. [ 7191.711877] uvcvideo: Non-zero status (-71) in video completion handler. [ 7202.622650] uvcvideo: Non-zero status (-71) in video completion handler. [ 7217.836386] uvcvideo: Non-zero status (-71) in video completion handler. [ 7227.088281] uvcvideo: Non-zero status (-71) in video completion handler. [ 7234.255051] uvcvideo: Non-zero status (-71) in video completion handler. [ 7305.931542] uvcvideo: Failed to set UVC probe control : -71 (exp. 26). [ 7305.944022] uvcvideo: Non-zero status (-71) in video completion handler. [ 7305.947522] uvcvideo: Non-zero status (-71) in video completion handler. [ 7305.951022] uvcvideo: Non-zero status (-71) in video completion handler. [ 7310.922775] uvcvideo: Failed to set UVC probe control : -110 (exp. 26). [ 7310.922777] uvcvideo: Failed to set UVC probe control : -110 (exp. 26). [ 7310.922806] uvcvideo: Failed to set UVC probe control : -110 (exp. 26). [ 7310.926210] uvcvideo: Failed to set UVC probe control : -71 (exp. 26). [ 7315.922435] uvcvideo: Failed to set UVC probe control : -110 (exp. 26). [ 7315.922440] uvcvideo: Failed to set UVC probe control : -110 (exp. 26). [ 7315.922444] uvcvideo: Failed to set UVC probe control : -110 (exp. 26). [ 7315.925864] uvcvideo: Failed to set UVC probe control : -71 (exp. 26). [ 7320.922092] uvcvideo: Failed to set UVC probe control : -110 (exp. 26). [ 7320.922095] uvcvideo: Failed to set UVC probe control : -110 (exp. 26). [ 7320.922102] uvcvideo: Failed to set UVC probe control : -110 (exp. 26). [ 7325.921786] uvcvideo: Failed to set UVC probe control : -110 (exp. 26). [ 7325.921788] uvcvideo: Failed to set UVC probe control : -110 (exp. 26). [ 7325.921792] uvcvideo: Failed to set UVC probe control : -110 (exp. 26). [ 7325.925220] uvcvideo: Failed to set UVC probe control : -71 (exp. 26). [ 7330.921421] uvcvideo: Failed to set UVC probe control : -110 (exp. 26). [ 7330.921424] uvcvideo: Failed to set UVC probe control : -110 (exp. 26). [ 7330.921427] uvcvideo: Failed to set UVC probe control : -110 (exp. 26). [ 7335.921066] uvcvideo: Failed to set UVC probe control : -110 (exp. 26). [ 7335.921071] uvcvideo: Failed to set UVC probe control : -110 (exp. 26). [ 7407.606228] xhci_hcd 0000:00:14.0: xHCI host not responding to stop endpoint command. [ 7407.606231] xhci_hcd 0000:00:14.0: Assuming host is dying, halting host. [ 7407.606276] xhci_hcd 0000:00:14.0: HC died; cleaning up [ 7407.606329] usb 1-1: USB disconnect, device number 20 [ 7407.606499] usb 2-2: USB disconnect, device number 74 [ 7407.606501] usb 2-2.2: USB disconnect, device number 77 [ 7407.606876] ftdi_sio ttyUSB0: failed to get modem status: -19 [ 7407.606879] ftdi_sio ttyUSB0: error from flowcontrol urb [ 7407.716786] usb 2-2.3: USB disconnect, device number 76 [ 7407.996673] usb 2-2.4: USB disconnect, device number 75 [ 7408.226521] usb 1-2: USB disconnect, device number 64 [ 7408.226731] usb 1-3: USB disconnect, device number 90 [ 7408.226916] usb 1-4: USB disconnect, device number 46 [ 7408.227061] ftdi_sio ttyUSB0: FTDI USB Serial Device converter now disconnected from ttyUSB0 [ 7408.227078] ftdi_sio 1-4:1.0: device disconnected [ 7408.227212] usb 1-5: USB disconnect, device number 4 [ 7408.227521] usb 1-7: USB disconnect, device number 5 [ 7408.346804] usb 2-5: USB disconnect, device number 88 [ 7408.346808] usb 2-5.2: USB disconnect, device number 91 [ 7408.546350] usb 1-10: USB disconnect, device number 6 [ 7408.736468] usb 2-5.3: USB disconnect, device number 90 [ 7408.886544] usb 2-5.4: USB disconnect, device number 89 If I remove xhci_pci and xhci_hcd, and try to reload them I get a segmentation default shakti ~ # modprobe -r xhci_pci shakti ~ # modprobe -r xhci_hcd shakti ~ # modprobe xhci_hcd shakti ~ # modprobe xhci_pci Segmentation fault shakti ~ # dmesg dmesg shows this at the end: [ 8071.052276] ------------[ cut here ]------------ [ 8071.052280] WARNING: CPU: 7 PID: 9330 at drivers/pci/msi.c:1049 pci_enable_msi_range+0x36/0x2e0() [ 8071.052281] Modules linked in: xhci_pci(+) xhci_hcd sha256_generic drbg ctr ccm binfmt_misc vboxnetadp(O) vboxnetflt(O) vboxdrv(O) joydev hid_logitech_hidpp uvcvideo videobuf2_vmalloc ftdi_sio videobuf2_memops videobuf2_v4l2 hid_logitech_dj usbserial videodev videobuf2_core btusb btrtl btbcm btintel bluetooth snd_hda_codec_hdmi nvidia_drm(PO) nvidia_modeset(PO) nvidia(PO) arc4 iwlmvm asus_nb_wmi asus_wmi sparse_keymap mac80211 snd_hda_codec_realtek snd_hda_codec_generic drm_kms_helper snd_hda_intel snd_hda_codec syscopyarea sysfillrect snd_hda_core sysimgblt fb_sys_fops snd_pcm drm snd_timer iwlwifi coretemp snd hwmon soundcore efi_pstore r8169 cfg80211 x86_pkg_temp_thermal mii i2c_i801 lpc_ich efivars wmi efivarfs [last unloaded: xhci_hcd] [ 8071.052304] CPU: 7 PID: 9330 Comm: modprobe Tainted: P O 4.5.2-gentoo #1 [ 8071.052305] Hardware name: ASUSTeK COMPUTER INC. G751JL/G751JL, BIOS G751JL.204 08/01/2015 [ 8071.052306] 0000000080000000 ffffffff8128c9dd 0000000000000000 0000000000000009 [ 8071.052308] ffffffff810727b2 ffffffff812c808e ffff88046e329000 0000000000000001 [ 8071.052309] ffff88033fce6000 ffff88033fce6230 ffffffff812c808e ffff88046e329098 [ 8071.052310] Call Trace: [ 8071.052313] [<ffffffff8128c9dd>] ? dump_stack+0x46/0x59 [ 8071.052317] [<ffffffff810727b2>] ? warn_slowpath_common+0x8f/0xa4 [ 8071.052318] [<ffffffff812c808e>] ? pci_enable_msi_range+0x36/0x2e0 [ 8071.052319] [<ffffffff812c808e>] ? pci_enable_msi_range+0x36/0x2e0 [ 8071.052323] [<ffffffffa0112c10>] ? xhci_run+0x3d9/0x632 [xhci_hcd] [ 8071.052326] [<ffffffff813c510c>] ? usb_add_hcd+0x47c/0x7da [ 8071.052328] [<ffffffff813d1d29>] ? usb_hcd_pci_probe+0x27b/0x39b [ 8071.052331] [<ffffffff81172336>] ? kernfs_add_one+0x11c/0x130 [ 8071.052333] [<ffffffffa000f508>] ? xhci_pci_probe+0x22/0x182 [xhci_pci] [ 8071.052336] [<ffffffff812b7878>] ? pci_device_probe+0x7e/0xe7 [ 8071.052338] [<ffffffff8134beb7>] ? driver_probe_device+0x10d/0x24d [ 8071.052339] [<ffffffff8134c04a>] ? __driver_attach+0x53/0x73 [ 8071.052340] [<ffffffff8134bff7>] ? driver_probe_device+0x24d/0x24d [ 8071.052342] [<ffffffff8134a626>] ? bus_for_each_dev+0x61/0x78 [ 8071.052343] [<ffffffff8134b62d>] ? bus_add_driver+0xe4/0x1d7 [ 8071.052344] [<ffffffffa001e000>] ? 0xffffffffa001e000 [ 8071.052346] [<ffffffff8134c71d>] ? driver_register+0x83/0xbb [ 8071.052346] [<ffffffffa001e000>] ? 0xffffffffa001e000 [ 8071.052348] [<ffffffff810003e8>] ? do_one_initcall+0xe2/0x15f [ 8071.052351] [<ffffffff810e79dd>] ? do_init_module+0x51/0x1b2 [ 8071.052353] [<ffffffff810c674b>] ? load_module+0x1807/0x1c35 [ 8071.052355] [<ffffffff810c3eca>] ? copy_module_from_fd+0x7f/0xd8 [ 8071.052356] [<ffffffff810c6ca5>] ? SyS_finit_module+0x51/0x5c [ 8071.052357] [<ffffffff810c6ca5>] ? SyS_finit_module+0x51/0x5c [ 8071.052360] [<ffffffff81545c1b>] ? entry_SYSCALL_64_fastpath+0x16/0x6e [ 8071.052361] ---[ end trace 61566651c88f6b61 ]--- [ 8071.052382] ------------[ cut here ]------------ [ 8071.052383] kernel BUG at drivers/pci/msi.c:368! [ 8071.052384] invalid opcode: 0000 [#1] PREEMPT SMP [ 8071.052385] Modules linked in: xhci_pci(+) xhci_hcd sha256_generic drbg ctr ccm binfmt_misc vboxnetadp(O) vboxnetflt(O) vboxdrv(O) joydev hid_logitech_hidpp uvcvideo videobuf2_vmalloc ftdi_sio videobuf2_memops videobuf2_v4l2 hid_logitech_dj usbserial videodev videobuf2_core btusb btrtl btbcm btintel bluetooth snd_hda_codec_hdmi nvidia_drm(PO) nvidia_modeset(PO) nvidia(PO) arc4 iwlmvm asus_nb_wmi asus_wmi sparse_keymap mac80211 snd_hda_codec_realtek snd_hda_codec_generic drm_kms_helper snd_hda_intel snd_hda_codec syscopyarea sysfillrect snd_hda_core sysimgblt fb_sys_fops snd_pcm drm snd_timer iwlwifi coretemp snd hwmon soundcore efi_pstore r8169 cfg80211 x86_pkg_temp_thermal mii i2c_i801 lpc_ich efivars wmi efivarfs [last unloaded: xhci_hcd] [ 8071.052404] CPU: 7 PID: 9330 Comm: modprobe Tainted: P W O 4.5.2-gentoo #1 [ 8071.052404] Hardware name: ASUSTeK COMPUTER INC. G751JL/G751JL, BIOS G751JL.204 08/01/2015 [ 8071.052405] task: ffff8803f03fa040 ti: ffff880340908000 task.ti: ffff880340908000 [ 8071.052406] RIP: 0010:[<ffffffff812c7eef>] [<ffffffff812c7eef>] free_msi_irqs+0x3d/0x15e [ 8071.052408] RSP: 0018:ffff88034090bae0 EFLAGS: 00010282 [ 8071.052409] RAX: ffff88046d71cc00 RBX: ffff88046e329000 RCX: ffff88046e400100 [ 8071.052409] RDX: 0000000000000000 RSI: 000000000000001a RDI: 0000000000000000 [ 8071.052410] RBP: ffff88007d4862c0 R08: ffff88046e400008 R09: 00000000fffffffa [ 8071.052411] R10: 0000000000000000 R11: 00000000000122a5 R12: 0000000000000000 [ 8071.052412] R13: ffff88046e329270 R14: 0000000000000001 R15: 00000000ffffffe4 [ 8071.052413] FS: 00007f347e43b700(0000) GS:ffff88047f1c0000(0000) knlGS:0000000000000000 [ 8071.052413] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 8071.052414] CR2: 00007fff2c09afb0 CR3: 000000045c546000 CR4: 00000000001406e0 [ 8071.052415] Stack: [ 8071.052415] ffff88046e329000 ffff88042dd81d40 00000000ffffffe4 00000000000000ff [ 8071.052417] ffffffff812c82ac 008688046e329098 ffff88033fce6000 ffff88033fce6230 [ 8071.052418] ffff88033fce6000 ffff88033fce6230 ffff88033fce6000 ffff88046e329000 [ 8071.052420] Call Trace: [ 8071.052421] [<ffffffff812c82ac>] ? pci_enable_msi_range+0x254/0x2e0 [ 8071.052423] [<ffffffffa0112c10>] ? xhci_run+0x3d9/0x632 [xhci_hcd] [ 8071.052425] [<ffffffff813c510c>] ? usb_add_hcd+0x47c/0x7da [ 8071.052426] [<ffffffff813d1d29>] ? usb_hcd_pci_probe+0x27b/0x39b [ 8071.052427] [<ffffffff81172336>] ? kernfs_add_one+0x11c/0x130 [ 8071.052429] [<ffffffffa000f508>] ? xhci_pci_probe+0x22/0x182 [xhci_pci] [ 8071.052431] [<ffffffff812b7878>] ? pci_device_probe+0x7e/0xe7 [ 8071.052432] [<ffffffff8134beb7>] ? driver_probe_device+0x10d/0x24d [ 8071.052433] [<ffffffff8134c04a>] ? __driver_attach+0x53/0x73 [ 8071.052434] [<ffffffff8134bff7>] ? driver_probe_device+0x24d/0x24d [ 8071.052435] [<ffffffff8134a626>] ? bus_for_each_dev+0x61/0x78 [ 8071.052436] [<ffffffff8134b62d>] ? bus_add_driver+0xe4/0x1d7 [ 8071.052437] [<ffffffffa001e000>] ? 0xffffffffa001e000 [ 8071.052438] [<ffffffff8134c71d>] ? driver_register+0x83/0xbb [ 8071.052438] [<ffffffffa001e000>] ? 0xffffffffa001e000 [ 8071.052439] [<ffffffff810003e8>] ? do_one_initcall+0xe2/0x15f [ 8071.052441] [<ffffffff810e79dd>] ? do_init_module+0x51/0x1b2 [ 8071.052442] [<ffffffff810c674b>] ? load_module+0x1807/0x1c35 [ 8071.052443] [<ffffffff810c3eca>] ? copy_module_from_fd+0x7f/0xd8 [ 8071.052445] [<ffffffff810c6ca5>] ? SyS_finit_module+0x51/0x5c [ 8071.052446] [<ffffffff810c6ca5>] ? SyS_finit_module+0x51/0x5c [ 8071.052448] [<ffffffff81545c1b>] ? entry_SYSCALL_64_fastpath+0x16/0x6e [ 8071.052448] Code: af 70 02 00 00 4c 39 ed 74 2e 83 7d 10 00 74 22 45 31 e4 44 3b 65 14 73 19 8b 7d 10 44 01 e7 e8 44 05 de ff 48 83 78 68 00 74 02 <0f> 0b 41 ff c4 eb e1 48 8b 6d 00 eb cd 48 8b 83 68 02 00 00 48 [ 8071.052466] RIP [<ffffffff812c7eef>] free_msi_irqs+0x3d/0x15e [ 8071.052467] RSP <ffff88034090bae0> [ 8071.052468] ---[ end trace 61566651c88f6b62 ]--- If you think of any more information I should look at, just mention it. Thanks. Brian On 05/16/16 12:52, Alan Stern wrote: > On Mon, 16 May 2016, Brian T. McKee wrote: > >> I sent a message to the group yesterday, but I suspect it was too big >> for it's own good and didn't make it to the list. > It did; I saw it. > >> I'm attempting to debug a USB problem where multiple UVC camera causes >> the USB driver to crash and shut down. All *HCI devices stop working. > If you could post a dmesg log showing how this happens, it might help. > >> I managed to get a USB serial port up and running on my laptop and >> connect it to an old machine with a built in serial port, as an attempt >> to get KGDB running, but alas, KGDB does not recognize /dev/ttyUSB0 as a >> valid device. >> >> It looks like KGDB does not support the EHCI debug cable anymore, > It should. If it doesn't, it's a regression. > >> although a crossover cable is available if that becomes an option. >> >> Can someone in the group advise me on how to debug this issue? I was >> hoping to get a back trace for you guys... > Have you considered logging in over the network? > > What exactly do you want to learn? kgdb may not be the best way of > learning it. > > The log in your previous message wasn't very intelligible. You had too > many debug options turned on, which is almost as bad as not having > enough. > > Alan Stern > -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
