From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758866Ab0JFJL7 (ORCPT ); Wed, 6 Oct 2010 05:11:59 -0400 Received: from mail-out.m-online.net ([212.18.0.10]:47498 "EHLO mail-out.m-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758819Ab0JFJL5 (ORCPT ); Wed, 6 Oct 2010 05:11:57 -0400 X-Auth-Info: YOCLCdOKlVlLZtWoLFDQocOxDuZEnhdbpD0QCnmNi/M= Message-ID: <4CAC3D94.9010408@grandegger.com> Date: Wed, 06 Oct 2010 11:12:52 +0200 From: Wolfgang Grandegger User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.12) Gecko/20100907 Fedora/3.0.7-1.fc12 Thunderbird/3.0.7 MIME-Version: 1.0 To: David Miller CC: masa-korg@dsn.okisemi.com, andrew.chih.howe.khor@intel.com, sameo@linux.intel.com, margie.foster@intel.com, netdev@vger.kernel.org, yong.y.wang@intel.com, linux-kernel@vger.kernel.org, socketcan-core@lists.berlios.de, mkl@pengutronix.de, chripell@fsfe.org, morinaga526@dsn.okisemi.com, meego-dev@meego.com, kok.howg.ewe@intel.com, joel.clark@intel.com, qi.wang@intel.com Subject: Re: [MeeGo-Dev][PATCH v3] Topcliff: Update PCH_CAN driver to 2.6.35 References: <002e01cb6486$2ed72cc0$66f8800a@maildom.okisemi.com> <20101005.114506.184852374.davem@davemloft.net> <000b01cb6503$962bc7f0$66f8800a@maildom.okisemi.com> <20101005.200904.71120150.davem@davemloft.net> In-Reply-To: <20101005.200904.71120150.davem@davemloft.net> X-Enigmail-Version: 1.0.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/06/2010 05:09 AM, David Miller wrote: > From: "Masayuki Ohtake" > Date: Wed, 6 Oct 2010 12:07:15 +0900 > >> Does your mail mean, for accepting upstream, NAPI is essential for >> CAN driver ? > > It is up to the CAN maintainers :-) Well, our SJA1000 reference driver does still not use NAPI. But NAPI is for CAN especially useful to avoid the infamous *bus error irq flooding*, which may hang low end systems if the interrupts are handled in the IRQ context. Ohtake, if your system can handle well such CAN bus error irq storms at 1MB/s, then NAPI is *not* a must to have. Anyway, as you are at it, I also suggest to use NAPI right from the beginning. Wolfgang. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfgang Grandegger Subject: Re: [MeeGo-Dev][PATCH v3] Topcliff: Update PCH_CAN driver to 2.6.35 Date: Wed, 06 Oct 2010 11:12:52 +0200 Message-ID: <4CAC3D94.9010408@grandegger.com> References: <002e01cb6486$2ed72cc0$66f8800a@maildom.okisemi.com> <20101005.114506.184852374.davem@davemloft.net> <000b01cb6503$962bc7f0$66f8800a@maildom.okisemi.com> <20101005.200904.71120150.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: andrew.chih.howe.khor-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, socketcan-core-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org, sameo-VuQAYsv1563Yd54FQh9/CA@public.gmane.org, margie.foster-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, yong.y.wang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, masa-korg-ECg8zkTtlr0C6LszWs/t0g@public.gmane.org, mkl-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, joel.clark-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, morinaga526-ECg8zkTtlr0C6LszWs/t0g@public.gmane.org, meego-dev-WXzIur8shnEAvxtiuMwx3w@public.gmane.org, kok.howg.ewe-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, chripell-VaTbYqLCNhc@public.gmane.org, qi.wang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org To: David Miller Return-path: In-Reply-To: <20101005.200904.71120150.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: socketcan-core-bounces-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org Errors-To: socketcan-core-bounces-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org List-Id: netdev.vger.kernel.org On 10/06/2010 05:09 AM, David Miller wrote: > From: "Masayuki Ohtake" > Date: Wed, 6 Oct 2010 12:07:15 +0900 > >> Does your mail mean, for accepting upstream, NAPI is essential for >> CAN driver ? > > It is up to the CAN maintainers :-) Well, our SJA1000 reference driver does still not use NAPI. But NAPI is for CAN especially useful to avoid the infamous *bus error irq flooding*, which may hang low end systems if the interrupts are handled in the IRQ context. Ohtake, if your system can handle well such CAN bus error irq storms at 1MB/s, then NAPI is *not* a must to have. Anyway, as you are at it, I also suggest to use NAPI right from the beginning. Wolfgang.