On Saturday 31 Dec 2011, Alan Stern wrote:
> On Fri, 30 Dec 2011, David Goodenough wrote:
> > Its title was "OOPS when attaching USB BeagleBone", and it appears
> > in the archive.
>
> Don't you find it rather annoying when people use pronouns whose
> antecedents aren't in the same region of text?
>
> > Unfortunately I was not subscribed at the time, so I can not reply to
> > it, but it appears no one else has either.
> >
> > Is this not the correct place to report OOPS in the usb system? If
> > not, can you suggest where I should report it?
>
> This mailing list is indeed the correct place to report problems in the
> USB subsystem. (On the other hand, it's worth nothing that the problem
> you reported actually occurred in the driver core, not in the USB
> subsystem -- not that it really matters.)
>
> There was nothing wrong with your report except the timing. You had
> the bad luck to bring up a problem at a time of year when almost nobody
> had the inclination to look at it.
>
> It appears that the bug was triggered by the udev rule containing the
> new_id attribute, but exactly what went wrong is not clear -- at least,
> not to me. You could try commenting out that rule and see if that
> helps.
>
> Is this bug fully repeatable?
Yes and no. It only happens when I insert the USB cable from the
BeagleBone, but it does not happen every time - sounds like a timing
problem to me. The host I am using is an elderly (and therefore not
very fast) laptop, the processor is not SMP.
There are 4 rules:-
ACTION=="add", SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_interface",
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="a6d0", DRIVER=="",
RUN+="/sbin/modprobe -b ftdi_sio"
ACTION=="add", SUBSYSTEM=="drivers", ENV{DEVPATH}=="/bus/usb-
serial/drivers/ftdi_sio", ATTR{new_id}="0403 a6d0"
ACTION=="add", KERNEL=="ttyUSB*", ATTRS{interface}=="BeagleBone",
ATTRS{bInterfaceNumber}=="00", SYMLINK+="beaglebone-jtag"
ACTION=="add", KERNEL=="ttyUSB*", ATTRS{interface}=="BeagleBone",
ATTRS{bInterfaceNumber}=="01", SYMLINK+="beaglebone-serial"
I have tried it without the last two, assuming it was the symlink
that was causing the problem, but removing them does not cure the
problem.
The first two seem rather important to getting it to work. Certainly if I
remove the whole file then I do not get the problem, but I also can not
communicate with the serial port on the device.
David
>
> Alan Stern
>
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