Re: [Libmtp-discuss] Permissions on USB device

[Alistair B. <a.j...@gm...>]

This looks like it could be https://sourceforge.net/p/libmtp/bugs/1474/

It appears to work after I copied mtp-probe from git master in to /lib/udev

On 12 December 2017 at 00:32, Alistair Buxton <a.j...@gm...> wrote:
> From what I can see the udev rules have a rule which catches unknown
> devices. This rule works correctly when the device is "plugged" into
> the virtual dummy_hcd driver, but for some reason it does not match
> when my code is running on a real USB board plugged in to a physical
> port.
>
> The rule is like this, after a couple thousand definitions for specific devices:
>
> # Autoprobe vendor-specific, communication and PTP devices
> ENV{ID_MTP_DEVICE}!="1", ENV{MTP_NO_PROBE}!="1",
> ENV{COLOR_MEASUREMENT_DEVICE}!="1", ENV{libsane_matched}!="yes",
> ATTR{bDeviceClass}=="00|02|06|ef|ff", PROGRAM="mtp-probe
> /sys$env{DEVPATH} $attr{busnum} $attr{devnum}", RESULT=="1",
> SYMLINK+="libmtp-%k", MODE="660", GROUP="audio",
> ENV{ID_MTP_DEVICE}="1", ENV{ID_MEDIA_PLAYER}="1"
>
> Here is the diff between the two lsusb -v:
>
> < Bus 001 Device 075: ID 0430:a4a2 Sun Microsystems, Inc. Ethernet
> (RNDIS and CDC ethernet)
> ---
>> Bus 007 Device 048: ID 0430:a4a2 Sun Microsystems, Inc. Ethernet (RNDIS and CDC ethernet)
> 18,23d17
> < OTG Descriptor:
> <   bLength                 3
> <   bDescriptorType         9
> <   bmAttributes         0x03
> <     SRP (Session Request Protocol)
> <     HNP (Host Negotiation Protocol)
> 27c21
> <     wTotalLength           42
> ---
>>     wTotalLength           39
> 57c51
> <         bEndpointAddress     0x01  EP 1 OUT
> ---
>>         bEndpointAddress     0x02  EP 2 OUT
> 67c61
> <         bEndpointAddress     0x82  EP 2 IN
> ---
>>         bEndpointAddress     0x85  EP 5 IN
>
> Bus 001 is real hardware and 007 is dummy_hcd. This is the same code,
> connected to the same host system.
>
> The only real difference is that the real hardware has this extra OTG
> descriptor.
>
> This seems to be down to mtp-probe somehow:
>
> Dec 11 22:20:24 al-desktop mtp-probe[2753]: checking bus 1, device 89:
> "/sys/devices/pci0000:00/0000:00:14.0/usb1/1-11/1-11.4/1-11.4.4"
> Dec 11 22:20:24 al-desktop mtp-probe[2753]: bus: 1, device: 89 was not
> an MTP device
>
> Dec 12 00:07:57 al-desktop mtp-probe[5814]: checking bus 7, device 50:
> "/sys/devices/platform/dummy_hcd.0/usb7/7-1"
> Dec 12 00:07:57 al-desktop mtp-probe[5814]: bus: 7, device: 50 was an MTP device
>
> --
> Alistair Buxton
> a.j...@gm...



-- 
Alistair Buxton
a.j...@gm...