Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755969Ab3GYNeR (ORCPT ); Thu, 25 Jul 2013 09:34:17 -0400 Received: from webmail.solarflare.com ([12.187.104.25]:11486 "EHLO webmail.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755491Ab3GYNeN (ORCPT ); Thu, 25 Jul 2013 09:34:13 -0400 Message-ID: <1374759243.18653.62.camel@deadeye.wl.decadent.org.uk> Subject: Re: [PATCH 1/1] TX throttling bug-fixing patch of AX88179_178A From: Ben Hutchings To: Ming Lei CC: Eric Dumazet , Oliver Neukum , Grant Grundler , Freddy Xin , David Miller , netdev , , LKML , ASIX Louis =?UTF-8?Q?=5B=E8=98=87=E5=A8=81=E9=99=B8=5D?= , "Allan Chou" Date: Thu, 25 Jul 2013 14:34:03 +0100 In-Reply-To: References: <1374311809-4155-1-git-send-email-freddy@asix.com.tw> <1374512879.4990.19.camel@edumazet-glaptop> <1374518312.1635.29.camel@bwh-desktop.uk.level5networks.com> <1374518841.4990.26.camel@edumazet-glaptop> <1374522471.1635.48.camel@bwh-desktop.uk.level5networks.com> <1374559827.4990.143.camel@edumazet-glaptop> <1374729058.23313.8.camel@edumazet-glaptop> Organization: Solarflare Communications Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.4.4-3 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Originating-IP: [88.96.1.126] X-TM-AS-Product-Ver: SMEX-10.0.0.1412-7.000.1014-20036.004 X-TM-AS-Result: No--26.668400-0.000000-31 X-TM-AS-User-Approved-Sender: Yes X-TM-AS-User-Blocked-Sender: No Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1583 Lines: 39 On Thu, 2013-07-25 at 13:25 +0800, Ming Lei wrote: > On Thu, Jul 25, 2013 at 1:10 PM, Eric Dumazet 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 Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/