[usbmtaa]

Hello,

I'm attempting to get a Mimo USB Mini-monitor UM-710S to work by using usb_modeswitch as described here (scroll down to find the bold "usb_modeswitch" heading).

I do not know how to properly interpret the results of lsusb. Here's what I get, same output under a dual-boot Lubuntu 13.04 32-bit and Fedora 18 32-bit:

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$ sudo lsusb -v -d 17e9:0040

Bus 001 Device 002: ID 17e9:0040 DisplayLink 
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass          255 Vendor Specific Class
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0        64
  idVendor           0x17e9 DisplayLink
  idProduct          0x0040 
  bcdDevice            0.00
  iManufacturer           1 Newnham Research
  iProduct                2 USB Display Adapter
  iSerial                 3 0040-000000
  bNumConfigurations      0
Device Qualifier (for other device speed):
  bLength                10
  bDescriptorType         6
  bcdUSB               2.00
  bDeviceClass          255 Vendor Specific Class
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0        64
  bNumConfigurations      1
Device Status:     0x0000
  (Bus Powered)

I compiled usb_modeswitch version 1.2.6 from source using usb-modeswitch-data-20130610 and these libusb versions:

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Lubuntu: libusb-dev          (2:0.1.12-23+nmu1ubuntu1)
Fedora : libusb-devel.i686   (1:0.1.3-11.fc18)

When I connect the device, dmesg reports (same info under Lubuntu and Fedora):

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[    2.687059] usb 1-4: new high-speed USB device number 2 using ehci_hcd
[    2.801809] usb 1-4: unable to read config index 0 descriptor/start: -32
[    2.801866] usb 1-4: chopping to 0 config(s)
[    2.802441] usb 1-4: New USB device found, idVendor=17e9, idProduct=0040
[    2.802448] usb 1-4: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[    2.802453] usb 1-4: Product: USB Display Adapter
[    2.802458] usb 1-4: Manufacturer: Newnham Research
[    2.802463] usb 1-4: SerialNumber: 0040-000000
[    2.802672] usb 1-4: no configuration chosen from 0 choices

I get identical terminal output under Lubuntu and Fedora when I do the following:

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sudo usb_modeswitch -v 17e9 -p 0040 -u 1

Looking for default devices ...
   found matching product ID
Getting the current device configuration ...
 OK, got current device configuration (0)
 Found device in default mode, class or configuration (1)
Accessing device 002 on bus 001 ...
Getting the current device configuration ...
 OK, got current device configuration (0)

After executing the above, I see segmentation faults reported by dmesg:

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Lubuntu: usb_modeswitch[4945]: segfault at  c ip 0804adf7 sp bfd36300 error 4 in usb_modeswitch[8048000+c000]
Fedora : usb_modeswitch[1882]: segfault at 11 ip 0804adbe sp bfe25ed0 error 4 in usb_modeswitch[8048000+c000]

Here are my questions:

1. Does the above lsusb output show there really is more than one configuration?
2. Would a segfault be triggered anyway if I tried usb_modeswitch on a device that only has one configuration? (Knowing the answer to this will help me determine whether I need to report the segfaults to the Lubuntu/Fedora developers.)

[Josh]

Your device does not appear in mass storage mode initially, so it's not likely that it needs usb_modeswitch. Also, it says it has only one configuration (bNumConfigurations 1) or even no configuration ((bNumConfigurations 0 ??); it's useless to try and switch to a different configuration in that case.

To be honest, I don't know what to make of that "other device speed" values ...

[helgaella99]

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