From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH 2/8] tg3: Allow screaming interrupt detection Date: Tue, 21 Apr 2009 01:41:58 -0700 (PDT) Message-ID: <20090421.014158.190780360.davem@davemloft.net> References: <1240247955.7012@xw6200> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, mchan@broadcom.com, benli@broadcom.com, andy@greyhouse.net To: mcarlson@broadcom.com Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:54725 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1753170AbZDUImG (ORCPT ); Tue, 21 Apr 2009 04:42:06 -0400 In-Reply-To: <1240247955.7012@xw6200> Sender: netdev-owner@vger.kernel.org List-ID: From: "Matt Carlson" Date: Mon, 20 Apr 2009 09:55:01 -0700 > The tg3 driver's ISR is coded to accept interrupts as its own if the > status block tag does not equal the last tag the driver has seen. The > last_tag field is updated from tg3_poll. In a screaming interrupt > situation from another device sharing tg3's IRQ, tg3_poll does not get > a chance to be called, so the last_tag will always be out of sync with > the status block tag. Consequently, the driver will continually > declare the screaming interrupts as its own, thus thwarting the > screaming interrupt detection logic. > > This patch solves the problem by creating a new last_irq_tag member and > recording the status block tag in the ISR. The ISR then checks the > last_irq_tag for interrupt ownership. > > Many thanks to John Marvin for the detailed bug report and analysis and > Michael Chan for the bugfix. > > Signed-off-by: Matt Carlson > Signed-off-by: Michael Chan > Tested-by: John Marvin Applied.