Hi, can anyone please help on the issue that resides on USB TX. Linux-2.6.28 USB stack: Gadget Chipset: OMAP34XX
Problem description:
-------------------- ping XXX.XXX.XX.X -t -l 20000 fails with failure message "Request timed out"
Debug procedure currently used:
-------------------------------
- Wireshark to monitor the USB interface for TX and RX
- RAM logs to trace if any error scenario occurs on TX and RX path.
Observations:
-------------
- Using Wireshark a. ping XXX.XXX.XX.X -t -l 10000 works fine. on RX ( ping request ) packets are divided into 1 -> 2 -> 3-> 4 -> 5 ... packets of almost same sizes upto the last packet are sent from Host ->
Device.
on TX ( ping reply ) packets are divided into 1 -> 2 -> 3-> 4 -> 5 ... packets of almost same sizes upto the last packet are sent from Device -> Host.
b. ping XXX.XXX.XX.X -t -l 20000 and above fails. on RX ( ping request ) packets are divided into 1 -> 2 -> 3-> 4 -> 5 ... packets of almost same sizes upto the last packet are sent from Host -> Device. on TX ( ping reply ) packets are divided into 1 -> 2 -> 3 packets of almost same sizes sent to the host, accepts next ping request packets completely and then sends -> 4
-> 5 ... packets of previous previous ping reply are sent from Device ->
Host.
- Using RAM logs a. No error scenarios wrt DMA / stall wrt transactions. b. In case of RX packets of size 1514 is divided into 0x200 + 0x200 +
are receieved via DMA c. In case of TX packet of size 1514 is programmed via DMA channel and triggered for the transaction. d. Good case vs Bad case logs almost shows no differences.
BTW A INTRODUCTION OF DELAY OF 4msec in musb_g_giveback( )resolves the issue.
But this is not the right approach.
Please let me know your suggestions.
Regards, Sandeep
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