From: Felipe Balbi <balbi@ti.com>
To: Chen Peter-B29397 <B29397@freescale.com>
Cc: Li Yang-R58472 <r58472@freescale.com>,
Enrico Scholz <enrico.scholz@sigma-chemnitz.de>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
"balbi@ti.com" <balbi@ti.com>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH] usb: gadget: fsl_udc_core: do not immediatly prime STATUS for IN xfer
Date: Thu, 6 Sep 2012 16:17:10 +0300 [thread overview]
Message-ID: <20120906131708.GJ29202@arwen.pp.htv.fi> (raw)
In-Reply-To: <F281D0F91ED19E4D8E63A7504E8A649803C67DA2@039-SN2MPN1-023.039d.mgd.msft.net>
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On Wed, Sep 05, 2012 at 02:10:39AM +0000, Chen Peter-B29397 wrote:
>
> >
> > Because the fsl_udc_core driver shares one 'status_req' object for the
> > complete ep0 control transfer, it is not possible to prime the final
> > STATUS phase immediately after the IN transaction. E.g. ch9getstatus()
> > executed:
> >
> > | req = udc->status_req;
> > | ...
> > | list_add_tail(&req->queue, &ep->queue);
> > | if (ep0_prime_status(udc, EP_DIR_OUT))
> > | ....
> > | struct fsl_req *req = udc->status_req;
> > | list_add_tail(&req->queue, &ep->queue);
> >
> > which corrupts the ep->queue list by inserting 'status_req' twice. This
> > causes a kernel oops e.g. when 'lsusb -v' is executed on the host.
> >
> > Patch delays the final 'ep0_prime_status(udc, EP_DIR_OUT))' by moving it
> > into the ep0 completion handler.
> >
> Enrico, thanks for pointing this problem.
>
> As "prime STATUS phase immediately after the IN transaction" is followed
> USB 2.0 spec, to fix this problem, it is better to add data_req for ep0.
> In fact, it is already at FSL i.mx internal code, just still not mainlined.
so, do I get an Acked-by to this patch ? Does it need to go on v3.6-rc
or can it wait until v3.7 merge window ?
--
balbi
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next prev parent reply other threads:[~2012-09-06 13:21 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-04 16:58 [PATCH] usb: gadget: fsl_udc_core: do not immediatly prime STATUS for IN xfer Enrico Scholz
2012-09-05 2:10 ` Chen Peter-B29397
2012-09-06 13:17 ` Felipe Balbi [this message]
2012-09-06 14:27 ` Enrico Scholz
2012-09-06 14:27 ` Felipe Balbi
2012-09-10 16:22 ` Felipe Balbi
2012-09-12 11:17 ` Li Yang-R58472
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