On Wed, Oct 21, 2015 at 11:39:04AM +0200, Erwin Van de Velde wrote: > Hi all, > > As advised, I retried with a more recent kernel (4.2.0), but I get a > similar result: > > I tested via 'echo 1 > /sys/bus/pci/ehci-pci/0000\:00\:1a.0/remove' > and 'echo 1 > /sys/bus/pci/rescan'. Why did you remove the PCI device? Do you have a PCI hotplug system that recan will work for? You are removing the whole USB host controller here, not just the USB device itself, it's a "fake" hotplug, which is odd, and your PCI device might not work correctly when you add it back... > There are two possible results: no > errors when removing the device and then the devices are reinserted > with the same ttyUSB number or, with an error: > 'usb_wwan_indat_callback: resubmit read urb failed. (-19)' (as shown > in the dmesg copied below) and then the numbers increase, even though > the ttyUSB devices with the previously used numbers have been removed > from /dev. On following attempts the numbers only remain the same or > increase, never reusing the freed ttyUSB numbers. Can someone please > tell me how I can prevent the error or circumvent the issue otherwise? > Sometimes the devices get stuck and resetting them via removal seems > to be the only option. > > Thanks in advance! > Erwin > > [ 623.366025] ehci-pci 0000:00:1a.0: remove, state 1 > [ 623.366042] usb usb1: USB disconnect, device number 1 > [ 623.366047] usb 1-1: USB disconnect, device number 2 > [ 623.366051] usb 1-1.1: USB disconnect, device number 4 > [ 623.366270] option1 ttyUSB6: GSM modem (1-port) converter now > disconnected from ttyUSB6 > [ 623.366294] option 1-1.1:1.0: device disconnected > [ 623.368715] option1 ttyUSB9: usb_wwan_indat_callback: resubmit read > urb failed. (-19) > [ 623.369327] option1 ttyUSB9: usb_wwan_indat_callback: resubmit read > urb failed. (-19) > [ 623.369863] option1 ttyUSB9: usb_wwan_indat_callback: resubmit read > urb failed. (-19) > [ 623.370398] option1 ttyUSB9: usb_wwan_indat_callback: resubmit read > urb failed. (-19) Those are normal, the device is being removed. > [ 623.371083] option1 ttyUSB9: GSM modem (1-port) converter now > disconnected from ttyUSB9 > [ 623.371097] option 1-1.1:1.2: device disconnected > [ 623.371315] option1 ttyUSB14: GSM modem (1-port) converter now > disconnected from ttyUSB14 Have you also shut down the userspace program that had these device nodes open? That's the issue here, what program has the device nodes open, if they don't close them, no matter what you do, the device nodes will not be recycled within the kernel. This isn't a kernel issue, it's a userspace issue to properly shut them down in order for the numbers to be reused. But even if they aren't reused, it's not a big deal, userspace should not care about the device node names at all, this isn't a problem, they will be recycled once userspace closes the device node, eventually. So focus on your userspace programs if you are really worried about the device numbers here. hope this helps, greg k-h -- 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
