Hello Andrzej, Thanks for the input.
On 12/11/2014 04:34 PM, Andrzej Pietrasiewicz wrote: > 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)? I was not using configfs at the start actually. g_ether was compiled as a module and it gives the same results. I switched to using configfs later when I came to know about it, as I also wanted to test serial and mass storage gadget. Did not stress test these functionalities, but, they seem to work. Tested serial bulk in/out, CDC ACM and gadget mass storage. > > 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. I have already tried this with two toolchains. One is Linaro GCC 4.7.2 pre-built and the other Linaro GCC 4.7.8 created by Open Embedded. > > AP --Sanchayan -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
