Date: Thu, 30 Jan 2014 14:39:47 -0800
From: Sarah Sharp <sarah.a.sharp@linux.intel.com>
To: David Laight <David.Laight@ACULAB.COM>
Cc: "'Mathias Nyman'" <mathias.nyman@linux.intel.com>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
        "dan.j.williams@intel.com" <dan.j.williams@intel.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [RFCv2 00/10] xhci: re-work command queue management
Message-ID: <20140130223947.GE14228@xanatos>
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 <063D6719AE5E284EB5DD2968C1650D6D0F6B532A@AcuExch.aculab.com>
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On Thu, Jan 30, 2014 at 02:25:48PM +0000, David Laight wrote:
> I think it would be much simpler to allocate a parallel array to the actual
> hardware command ring that contains the additional information for the request
> (instead of allocating it pre-request).
> This would immediately solve any problems allocating the memory from interrupt
> context and failing to free in correctly in all the code paths.
> 
> A similar solution could be used for the transfer rings thus removing the
> need to the 'td' list - which there are reports of it failing to find transfers
> and the code paths for aborting isoch transfers are badly broken.
> 
> Adding another list that will have its own set of bugs seems retrograde top me.

I do not have a problem with it.  The shadow ring is an optimization we
can look at later.

Sarah Sharp
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