OMAP3530 MUSB OTG: usb-to-ethernet link goes down sporadically

Kalaiselvan Rajagopal

Other Parts Discussed in Thread: OMAP3530

Hi,

We've been using OMAP3530 in one of our products and recently migrated to 2.6.32 kernel (4_01_00_09 PSP based). While doing some performance test using iperf on USB-to-Ethernet, we noticed that the link goes down-up-down-up.. sporadically. This happens only on the OTG port. On the EHCI port, the test pass without such issues. We are using ASIX 88772A based USB ethernet adapter for this testing. We verified the same hardware on 2.6.22, everything works good. So we are sure that it is not an hardware issue.

Here is the iperf output

********************************************************************************

------------------------------------------------------------

Client connecting to 172.1.1.2, TCP port 5001

TCP window size: 16.0 KByte (default)

------------------------------------------------------------

[ 3] local 172.1.1.1 port 43183 connected with 172.1.1.2 port 5001

eth0: link up, 100Mbps, full-duplex, lpa 0x45E1

[ ID] Interval Transfer Bandwidth

[ 3] 0.0-11.7 sec 80.3 MBytes 57.4 Mbits/sec

********************************************************************************

The USB bus log shows that there are quite a few control transfers while the link goes down. Perhaps, the link goes down because such control transfers.

Here is the snapshot of USB bus log. Any clue???