From: Mark Lord <mlord@pobox.com>
To: Alan Stern <stern@rowland.harvard.edu>,
Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: David Laight <David.Laight@ACULAB.COM>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
David Miller <davem@davemloft.net>,
Dan Williams <dan.j.williams@intel.com>,
"Nyman, Mathias" <mathias.nyman@intel.com>,
Freddy Xin <freddy@asix.com.tw>
Subject: Re: [PATCH RFC 1/1] usb: Tell xhci when usb data might be misaligned
Date: Thu, 30 Jan 2014 16:48:41 -0500 [thread overview]
Message-ID: <52EAC8B9.2070906@pobox.com> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1401301630340.31548-100000@netrider.rowland.org>
On 14-01-30 04:43 PM, Alan Stern wrote:
> On Thu, 30 Jan 2014, Sarah Sharp wrote:
>
>> It should not matter what alignment or length of scatter-gather list the
>> upper layers pass the xHCI driver, it should just work. I want to do
>> this fix right, by changing the fundamental way we queue TRBs to the
>> rings to fit the TD rules. We should break each TD into fragment-sized
>> chunks, and add a link TRB in the middle of a segment where necessary.
>
> That's a good plan. However _some_ restriction will turn out to be
> necessary.
>
> For example, what will you do if a driver submits an SG list containing
> 300 elements, each 3 bytes long?
Allocate a contiguous (bounce) buffer and copy the fragments to/from it?
--
Mark Lord
Real-Time Remedies Inc.
mlord@pobox.com
next prev parent reply other threads:[~2014-01-30 21:48 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-30 21:18 [PATCH RFC 1/1] usb: Tell xhci when usb data might be misaligned Sarah Sharp
2014-01-30 21:39 ` Mark Lord
2014-01-30 21:42 ` Mark Lord
2014-01-30 21:43 ` Alan Stern
2014-01-30 21:48 ` Mark Lord [this message]
2014-01-30 21:55 ` Sarah Sharp
2014-01-30 22:05 ` Bjørn Mork
2014-01-30 22:07 ` Alan Stern
2014-01-30 21:50 ` Bjørn Mork
2014-01-30 22:15 ` Sarah Sharp
2014-01-31 0:17 ` Ming Lei
2014-01-31 19:00 ` Sarah Sharp
2014-02-01 7:54 ` Ming Lei
2014-02-01 13:30 ` Mark Lord
2014-02-01 14:18 ` Ming Lei
2014-02-01 20:05 ` Mark Lord
[not found] ` <52ED5381.2010106-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org>
2014-02-03 9:54 ` David Laight
2014-02-03 17:56 ` Sarah Sharp
2014-02-03 17:55 ` Sarah Sharp
2014-01-31 15:22 ` David Laight
2014-01-31 10:14 ` David Laight
2014-01-31 13:21 ` Peter Stuge
2014-01-31 13:52 ` David Laight
-- strict thread matches above, loose matches on Subject: below --
2014-01-30 16:00 David Laight
[not found] ` <063D6719AE5E284EB5DD2968C1650D6D0F6B5486-VkEWCZq2GCInGFn1LkZF6NBPR1lH4CV8@public.gmane.org>
2014-01-30 16:17 ` Peter Stuge
[not found] ` <20140130161721.25560.qmail-Y+HMSxxDrH8@public.gmane.org>
2014-01-30 16:30 ` David Laight
[not found] ` <063D6719AE5E284EB5DD2968C1650D6D0F6B553D-VkEWCZq2GCInGFn1LkZF6NBPR1lH4CV8@public.gmane.org>
2014-01-30 16:35 ` Peter Stuge
2014-01-31 9:30 ` David Laight
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