Data Transmission Error with OHCI Host Controller

Hi Guys,

I have a problem with bluez on a arm platform. Here is the detail:
On the arm embedded platform, I invoke this command
l2ping -s 667 BDADDR
to test the bluetooth L2CAP connection, where BDADDR is the bluetooth address of my Linux/Bluez laptop. At the same time, I use
hcidump -x -R
on my laptop to monitor the bluetooth traffic. The problem is that the data I sent from the embedded arm platform got corrupted on receptioin. After a careful check, I found that the error has the following pattern: Some bytes of the ACL data packet, which corresponding to the L2CAP Echo Request Command, will have some 4 bytes of its content changed from valid data to 4 bytes of zero on occasion. And this change-to-zero error may occur several times in a ACL Packet sometimes. The distance between consecutive errors is always a multiple of 64-bytes which is the maxPacketSize of the USB pipe of the bluetooth dongle. The offset of the error position in the ACL Packet is always 64*i+4-64*i+7(4 bytes), where 'i' is an integer.

I am really confused. I have checked the skb and urb associated with the ACL Packet. And they both looks fine(content correct). So where could the problem lies in? Has anyone have had such a problem before? Any clue or hints are welcome!

Is this an known bug of OHCI HC driver usb-ohci in kernel 2.4.21? What makes me more confused is that the Usb Storage Disk works great on the embedded system.

I'm using linux-2.4.21 with patch-linux-2.4.21-mh10 and a cirrus edb9312 embedded arm platform which has a OHCI-Compatible USB Host Controller. The bluetooth dongle is a CSR one which works normally on my laptop PC.

Thank you in advance, guys.

Regards

Tianlei

For the fashion of Minas Tirith was such that it was built on seven levels,
each delved into a hill, and about each was set a wall, and in each wall
was a gate.
		-- J.R.R. Tolkien, "The Return of the King"

	[Quoted in "VMS Internals and Data Structures", V4.4, when
	 referring to system overview.]


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