Re: [PATCH] [musb_hdrc]: fix bug - EOVERFLOW failure when do usb gadget zero test t14

On Wed, Jun 25, 2008 at 7:35 PM, Felipe Balbi <[email protected]> wrote:
> On Wed, Jun 25, 2008 at 02:33:25PM +0800, ext Bryan Wu wrote:
>> >From f77853398c3c5f88ea7833ecb15546bf39023b00 Mon Sep 17 00:00:00 2001
>> From: Bryan Wu <[email protected]>
>> Date: Wed, 25 Jun 2008 14:29:33 +0800
>> Subject: [PATCH] [musb_hdrc]: fix bug - EOVERFLOW failure when do usb
>> gadget zero test t14
>>
>> https://blackfin.uclinux.org/gf/project/uclinux-dist/tracker/?action=TrackerItemEdit&tracker_id=141&tracker_item_id=4141
>>
>> Sometimes the last IN request will got error response which will
>> trigger EOVERFLOW error on USB host side.
>> We need to flush fifo after a whole trasfer.
>
> It looks fine.
>
> I'll test it a bit more and meld it on the patch going to mailine on
> next merge window ;-)
>

Please hold for a while, our tester reported that the bug still could
be found on Blackfin. Even with this patch, the test will fail
randomly.
For example, run testcase t14 10 times, 1 or 2 tests failed.

From the data captured in Lecory USB analyzer, I think there are some
bug in the OTG module:
1. PC Host send SETUP transfer to ep0 to tell gadget that Host will
write 151 bytes to gadget (for example)
2. PC host send a series of OUT trasnfers for gadget, so gadget got
the 151 bytes from host
3. PC host send IN pakcet for STATUS transfer, but gadget will report
a garbage data 1byte or 2bytes instead of ZERO byte.

It seems that the bad response is automatically done by hardware. Do
you find similar things in Davinci/OMAP platform?

Thanks
-Bryan
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