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Subject: Re: [PATCH 5/7] usb: gadget: fsl_udc: postpone freeing current dTD
From: Christoph Fritz <chf.fritz@googlemail.com>
To: balbi@ti.com
In-Reply-To: <20121019103039.GF11191@arwen.pp.htv.fi>
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Date: Fri, 19 Oct 2012 12:46:48 +0200
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Cc: Estevam Fabio-R49496 <r49496@freescale.com>,
 Li Yang-R58472 <r58472@freescale.com>,
 Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
 Chen Peter-B29397 <B29397@freescale.com>,
 Sascha Hauer <s.hauer@pengutronix.de>, linux-usb@vger.kernel.org,
 "Hans J. Koch" <hjk@hansjkoch.de>, Daniel Mack <daniel@caiaq.de>,
 Christian Hemp <c.hemp@phytec.de>, linuxppc-dev@lists.ozlabs.org,
 Teresa Gamez <T.Gamez@phytec.de>,
 Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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On Fri, 2012-10-19 at 13:30 +0300, Felipe Balbi wrote:
> On Fri, Oct 19, 2012 at 12:24:43PM +0200, Christoph Fritz wrote:
> > USB controller may access a wrong address for the dTD (endpoint transfer
> > descriptor) and then hang. This happens a lot when doing tests with
> > g_ether module and iperf, a tool for measuring maximum TCP and UDP
> > bandwidth.
> > 
> > This hardware bug is explained in detail by errata number 2858 for i.MX23:
> > http://cache.freescale.com/files/dsp/doc/errata/IMX23CE.pdf
> > 
> > All (?) SOCs with an IP from chipidea suffer from this problem.
> > mv_udc_core fixes this bug by commit daec765.  There still may be
> > unfixed drivers.
> 
> why aren't you using that driver instead ? Is it really necessary to
> keep this driver around ? I would really like to see uniformization
> towards that, if you use the same IP, then the same driver ought to
> suffice.
> 
> What's the reason for not using drivers/usb/chipidea ?
> 

I thought about this too but wasn't able to use chipidea with
MXC_EHCI_INTERNAL_PHY as it's called in fsl_udc.

Sascha, do you know if i.mx35 works with usb/chipidea?

Thanks
 -- Christoph