Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755499AbZLDBU0 (ORCPT ); Thu, 3 Dec 2009 20:20:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754846AbZLDBUX (ORCPT ); Thu, 3 Dec 2009 20:20:23 -0500 Received: from p01c11o145.mxlogic.net ([208.65.144.68]:49468 "EHLO p01c11o145.mxlogic.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751970AbZLDBUW convert rfc822-to-8bit (ORCPT ); Thu, 3 Dec 2009 20:20:22 -0500 X-MXL-Hash: 4b1863dd524f4ebb-854619c402b976ff3843cd8a1970f1a51d70d509 X-MimeOLE: Produced By Microsoft Exchange V6.5 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Subject: RE: [PATCH 2.6.32 3/3] net: Make ks8851 snl work under Beagle Zippy combo board Date: Thu, 3 Dec 2009 17:17:09 -0800 Message-ID: <14385191E87B904DBD836449AA30269D4F2135@MORGANITE.micrel.com> In-Reply-To: <20091203.160511.211490797.davem@davemloft.net> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [PATCH 2.6.32 3/3] net: Make ks8851 snl work under Beagle Zippy combo board Thread-Index: Acp0dXNlLZArAeE4TvSZpH/UxTb2MQAB1Lkg References: <14385191E87B904DBD836449AA30269D021A42@MORGANITE.micrel.com> <20091203.160511.211490797.davem@davemloft.net> From: "Ha, Tristram" To: "David Miller" Cc: , , X-OriginalArrivalTime: 04 Dec 2009 01:20:27.0858 (UTC) FILETIME=[F67DAB20:01CA747F] X-Spam: [F=0.2000000000; CM=0.500; S=0.200(2009113001)] X-MAIL-FROM: X-SOURCE-IP: [65.218.208.2] X-AnalysisOut: [v=1.0 c=1 a=7GNLPhxcCykA:10 a=J3BOMSfJb05aRia9DmE+FQ==:17 ] X-AnalysisOut: [a=Q4n7fi2PAAAA:8 a=rIV8yS8U-Ialy3RWZCsA:9 a=I1EBxjxhta6g_p] X-AnalysisOut: [SnijzobCTOpgwA:4 a=yJsD6ztlz_8A:10] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1898 Lines: 42 David Miller wrote: > From: "Ha, Tristram" > Date: Thu, 3 Dec 2009 13:30:03 -0800 > >> From: Tristram Ha >> >> The Micrel KSZ8851 SNL Ethernet chip is used in the OMAP Beagle Zippy combo board. Requesting >> interrupt using level triggering flag hangs the system because the interrupt handling routine >> is called continually. Using edge triggering avoids this problem. As a result, disabling >> interrupt may not be necessary. >> >> Signed-off-by: Tristram Ha > > You say "may not be necessary", do you actually know for sure? > > This seems questionable, if the interrupt disabling was there for a reason what has changed to > make it such that it is no longer necessary? I have tested the KSZ8851 SNL driver using the OMAP Beagle Zippy combo board, developed by Tin Can Tools. Ben Dooks, who implemented the original driver, has his own KSZ8851 SNL evaluation board, but he probably did not run any performance test on the driver. I did sent him the changes before so that he can verify on his board, but I have not received any response. So I really do not know if interrupt disabling is necessary or not. But from my understanding of the SPI network driver model, it is almost required the interrupt be edge triggered, as the hardware interrupt cannot be disabled inside the actual interrupt handling routine. So if the interrupt is level triggered, the interrupt routine will be called continually, and there is no chance for the workqueue to disable the interrupt. As the interrupt is edge triggered, I do not think the interrupt needs to be disabled. -- 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/