From: Ian Jeffray <ian@emobix.co.uk>
To: Christian Lamparter <chunkeey@googlemail.com>
Cc: Larry Finger <Larry.Finger@lwfinger.net>, linux-wireless@vger.kernel.org
Subject: Re: r8712u driver - on ARM
Date: Sat, 01 Oct 2011 19:10:48 +0100 [thread overview]
Message-ID: <4E8757A8.1010302@emobix.co.uk> (raw)
In-Reply-To: <201110012001.05111.chunkeey@googlemail.com>
On 01/10/2011 19:01, Christian Lamparter wrote:
> On Saturday 01 October 2011 19:52:37 Larry Finger wrote:
>> On 10/01/2011 11:22 AM, Christian Lamparter wrote:
>>> On Saturday 01 October 2011 18:01:08 Larry Finger wrote:
>>>> Ian,
>>>>
>>>> Most of the skb assignments in r8712u are aligned OK and most aligned on
>>>> 512-byte boundaries, but there was one that had the minimal offset of 14 bytes.
>>>> The attached patch should fix it. Does it help?
>>> Interesting, this "patch" goes in a completely different direction.
>>> Can you tell me where the driver aligns the frames which will be
>>> xmitted by the device [i.e.: which is passed to the usb subsystem
>>> by usb_submit_urb]? Because that's what actually matters.
>>
>> In this driver, all references are to _usb_submit_urb(), which is defined to be
>> usb_submit_urb() in one of the header files. That made it easy to insert a test
>> for misalignment of the DMA buffer as follows:
<snip>
>> +static inline int _usb_submit_urb(struct urb *urb, gfp_t mem_flags)
>> +{
>> + if (urb->transfer_dma& 3) {
<snip>
> I think you need to check transfer_buffer and not transfer_dma.
I tried checking both transfer_buffer and transfer_dma and all
were always word aligned. (At least on Blackfin)
Ian.
--
Ian Jeffray ian@emobix.co.uk Tel: +44 (0) 141 221 8449
emobix Limited, Suite 5/5, 29 St Vincent Place, Glasgow, G1 2DT
Registered in Scotland; Company No. 371276 - VAT No. 983 4833 78
next prev parent reply other threads:[~2011-10-01 18:10 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-27 15:36 r8712u driver - on ARM Ian Jeffray
2011-09-27 16:24 ` Larry Finger
2011-09-30 18:39 ` Ian Jeffray
2011-09-30 19:06 ` Christian Lamparter
2011-10-01 0:51 ` Larry Finger
2011-10-01 16:01 ` Larry Finger
2011-10-01 16:22 ` Christian Lamparter
2011-10-01 17:52 ` Larry Finger
2011-10-01 18:01 ` Christian Lamparter
2011-10-01 18:10 ` Ian Jeffray [this message]
2011-10-01 18:49 ` Larry Finger
2011-10-01 18:54 ` Christian Lamparter
2011-10-01 19:24 ` Larry Finger
2011-10-01 23:24 ` Ian Jeffray
2011-10-12 15:30 ` Ian Jeffray
2011-10-12 17:28 ` Larry Finger
2011-10-01 17:00 ` Ian Jeffray
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