[Bug 874181] Re: brltty daemon prevents creation of ttyUSB0 device link

[Samuel thibault]

Dave Mielke, le Wed 09 Nov 2011 10:44:57 -0500, a écrit :
> I wonder if there's a way to figure out which serial device is associated with
> a given USB device.

I believe so: I've just plugged a converter:

[161835.668469] usb 2-1.1.1: new full speed USB device number 9 using ehci_hcd
[161835.765607] usb 2-1.1.1: New USB device found, idVendor=0403, idProduct=6001
[161835.765612] usb 2-1.1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[161835.765616] usb 2-1.1.1: Product: USB SERIAL CONVERTER
[161835.765618] usb 2-1.1.1: Manufacturer: FTDI
[161835.765621] usb 2-1.1.1: SerialNumber: ftCEGJTT
[161835.893841] usbcore: registered new interface driver usbserial
[161835.893866] USB Serial support registered for generic
[161835.893926] usbcore: registered new interface driver usbserial_generic
[161835.893928] usbserial: USB Serial Driver core
[161835.899462] USB Serial support registered for FTDI USB Serial Device
[161835.899774] ftdi_sio 2-1.1.1:1.0: FTDI USB Serial Device converter detected
[161835.899813] usb 2-1.1.1: Detected FT232BM
[161835.899815] usb 2-1.1.1: Number of endpoints 2
[161835.899818] usb 2-1.1.1: Endpoint 1 MaxPacketSize 64
[161835.899821] usb 2-1.1.1: Endpoint 2 MaxPacketSize 64
[161835.899823] usb 2-1.1.1: Setting MaxPacketSize 64
[161835.900162] usb 2-1.1.1: FTDI USB Serial Device converter now attached to ttyUSB0
[161835.900178] usbcore: registered new interface driver ftdi_sio
[161835.900181] ftdi_sio: v1.6.0:USB FTDI Serial Converters Driver

and there is a /sys/bus/usb/devices/2-1.1.1/2-1.1.1:1.0/ttyUSB0
directory. Conversely, /sys/dev/char/188:0 is a symlink to
../../devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.1/2-1.1.1/2-1.1.1:1.0/ttyUSB0/tty/ttyUSB0/

> If so, perhaps brltty could make that translation and then
> automatically switch to sertal I/O using the device.

That however will still let brltty emit some characters to the device,
which can probably upset it.

> I don't have a USB to serial adapter here to check. Maybe I should
> just go spend some money and get one.

That's a useful thing to have under hand anyway :)

Samuel

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Title:
  brltty daemon prevents creation of ttyUSB0 device link

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