Hello,
W dniu 11.12.2014 o 11:38, Sanchayan Maity pisze:
Hello,
I am working on a Freescale Cortex-A5 Vybrid Processor. The chip core is clocked at 500MHz and the USB IP core for this
is by Chip-idea. I am running a 3.18-rc5 kernel on it and trying to use the USB gadget functionality. To be more
specific the CDC ECM class. Currently, I cannot use this properly. If I use just "ping" to check, it works
fine, but, after running iperf, even one transaction doesn't complete or completes rarely. Checking the CDC Ether
interface with Wireshark shows, TCP Dup Ack messages and checking the USB bus with Wireshark, shows packets with USB
Protocol Error -71 at one point and after that packets with USB connection Reset -104 error. If it's of any
significance, I have Arch Linux with the 3.18 kernel running on my laptop with which the Vybrid connects. On the host
side, the only error dmesg shows is "kevent 12 may have been dropped". I guess this is connected to the
"TCP Previous Segment not captured" and "TCP Dup ACK" messages.
My script for the gadget configuration is as below:
Two pointers which might/might not be helpful:
1) Can you reproduce the same behaviour using a legacy gadget, that is,
when your gadget is not composed with configfs but rather loaded as a module
(g_ether for example)?
2) Once upon a time I had a very strange error:
http://www.spinics.net/lists/linux-usb/msg99135.html
The communication over ethernet gadget used to break randomly.
It turned out it was a toolchain error.
AP
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