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Date:      Thu, 5 May 2011 10:09:55 +0200
From:      Hans Petter Selasky <hselasky@c2i.net>
To:        Trevor Blackwell <trevor@anybots.com>
Cc:        freebsd-usb@freebsd.org
Subject:   Re: Clearing stalls: usbd_xfer_set_stall vs usbd_do_clear_stall_callback
Message-ID:  <201105051009.55454.hselasky@c2i.net>
In-Reply-To: <BANLkTi=8--eu8%2BxWt26eJP3P3DYQ0En%2BSg@mail.gmail.com>
References:  <BANLkTik9MDy_tS3s78xG9VtbTaW%2BnCoM9A@mail.gmail.com> <201105050841.56095.hselasky@c2i.net> <BANLkTi=8--eu8%2BxWt26eJP3P3DYQ0En%2BSg@mail.gmail.com>

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On Thursday 05 May 2011 09:15:09 Trevor Blackwell wrote:
> 8.2-STABLE. I'm willing to run whatever.
> 
> I suspect the problem I'm having is the same as this:
> http://kerneltrap.org/mailarchive/linux-usb/2009/5/15/5761363
> 
> I can manually kick it out of the wedged state by sending a RESET_TT
> transaction to the hub with usbconfig -d ugen1.3 do_request 0x23 0x09
> 0x0000 0x0001 0
> 
>   (UT_WRITE_CLASS_OTHER, UR_RESET_TT)
> 
> I'm working on adding code to do this. My current hack is to do it from
> uhub_explore. When my driver tries to do a clear-stall and gets a timeout
> error from the clear-stall, it sets a flag on the parent_hs_hub to request
> a RESET_TT. uhub_explore notices the flag and does it.
> 
> Possibly I could also add it to usb_do_clear_stall_callback, but I don't
> think I can call usb_do_request from inside a callback.
> 
> Any suggestions?

Hi,

I think it is best to do this from the root HUB thread, then the operation 
gets properly serialised. Then the clear-stalls requests will simply be 
pending until normal operation is established.

Could a control endpoint timeout in general imply that the parent High Speed 
HUB, if any, should be reset?

--HPS



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