I am using a modified ACM driver to talk to a communications device. On
one machine the driver seems to work ok and I am able to open a tty port
to it. However on a different machine no such luck, the open to a tty
gives a bad file descriptor. Don't pay any attention to that; the error
is further down...
Both machines are using a usb-uhci.o module. Both are running 2.2.15 with
the most recent backport. On one machine no error messages, on the other
I am getting this in the log:
Jun 13 14:52:40 localhost kernel: usb-uhci-debug.h: TD @c11bfda0/011BFDA0, Ma
xLen=3f DT0 EP=3 Dev=2 PID=( IN ) buf=01f916f0
Jun 13 14:52:40 localhost kernel: usb-uhci-debug.h: Len=7ff e2 SPD IOC
CRC/Timeo
Jun 13 14:52:40 localhost kernel: usb-uhci-debug.h: TD Link Terminate
Ok, so I looked at it on the analyzer.
It goes something like this:
IN ADDR=2 ENDP=5 -> DATA=FF 00 -> ACK
SETUP=0xB4 ADDR=2 ENDP=0 -> ACK
IN ADDR=2 ENDP=3 DATA =00 00 00 00 -> ACK
IN ADDR=2 ENDP=0 -> NAK
IN ADDR=2 ENDP=0 -> STALL(0x78)
Then it goes into some odd behavior where it does INs to ENDP=3 and gets
zero length data packets back.
On the working machine instead of a STALL it gets another NAK and then it
does another IN and gets a 0 length data block. It then seems to proceed
normally.
Since the device, driver, usb stack, kernel are all the same... I suspect
some incompatibility with my host controller and the stack. Any thoughts?
I have put the two traces online at:
http://www.eecs.umich.edu/~mcorner/usbworking.usb
http://www.eecs.umich.edu/~mcorner/usbnotworking.usb
Thanks.
----
Mark Douglas Corner
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