From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ben Hutchings <bhutchings@solarflare.com>
Subject: Re: [PATCH 1/1] TX throttling bug-fixing patch of AX88179_178A
Date: Thu, 25 Jul 2013 14:34:03 +0100
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Cc: Eric Dumazet <eric.dumazet@gmail.com>,
	Oliver Neukum <oliver@neukum.org>,
	Grant Grundler <grundler@google.com>,
	Freddy Xin <freddy@asix.com.tw>,
	David Miller <davem@davemloft.net>,
	netdev <netdev@vger.kernel.org>, <linux-usb@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	ASIX Louis =?UTF-8?Q?=5B=E8=98=87=E5=A8=81=E9=99=B8=5D?=
	<louis@asix.com.tw>, "Allan Chou" <allan@asix.com.tw>
To: Ming Lei <tom.leiming@gmail.com>
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On Thu, 2013-07-25 at 13:25 +0800, Ming Lei wrote:
> On Thu, Jul 25, 2013 at 1:10 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> > On Thu, 2013-07-25 at 10:28 +0800, Ming Lei wrote:
> >
> >>
> >> It depends if size of sg buffer(except for last one) in the sg list can be
> >> divided by usb endpoint's max packet size(512 or 1024), at least there
> >> is the constraint:
> >>
> >> http://git.kernel.org/cgit/linux/kernel/git/gregkh/usb.git/commit/?h=usb-next&id=10e232c597ac757e7f8600649f7e872e86de190f
> >>
> >> I am wondering if network stack can meet that.  If not, it might be a
> >> bit difficult
> >> because lots of USB host controller don't support that, and driver may have
> >> to support SG and non-SG at the same time for working well on all HCs.
> >
> > I do not see the problem.
> >
> > If one skb has 2 fragments of 32KB, couldn't they be split into 64 1K
> > segments by the device driver ?
> 
> OK, if length of fragments of all SKBs from network stack can always guarantee
> to be divided by 1024, that is fine,  seems I worry about too much, :-)

Not that I have any experience with USB drivers, but perhaps
usb_sg_init()?

Ben.

-- 
Ben Hutchings, Staff Engineer, Solarflare
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