From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753828Ab1HTQXU (ORCPT ); Sat, 20 Aug 2011 12:23:20 -0400 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:39598 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752969Ab1HTQXT (ORCPT ); Sat, 20 Aug 2011 12:23:19 -0400 Date: Sat, 20 Aug 2011 17:21:56 +0100 From: Alan Cox To: mikeci@acm.org Cc: "Jiri Slaby" , Subject: Re: Possible bug in 8250.c Message-ID: <20110820172156.1ece472c@lxorguk.ukuu.org.uk> In-Reply-To: <29681.1313801904@sonic.net> References: <29681.1313801904@sonic.net> X-Mailer: Claws Mail 3.7.9 (GTK+ 2.24.4; x86_64-redhat-linux-gnu) Face: iVBORw0KGgoAAAANSUhEUgAAADAAAAAwBAMAAAClLOS0AAAAFVBMVEWysKsSBQMIAwIZCwj///8wIhxoRDXH9QHCAAABeUlEQVQ4jaXTvW7DIBAAYCQTzz2hdq+rdg494ZmBeE5KYHZjm/d/hJ6NfzBJpp5kRb5PHJwvMPMk2L9As5Y9AmYRBL+HAyJKeOU5aHRhsAAvORQ+UEgAvgddj/lwAXndw2laEDqA4x6KEBhjYRCg9tBFCOuJFxg2OKegbWjbsRTk8PPhKPD7HcRxB7cqhgBRp9Dcqs+B8v4CQvFdqeot3Kov6hBUn0AJitrzY+sgUuiA8i0r7+B3AfqKcN6t8M6HtqQ+AOoELCikgQSbgabKaJW3kn5lBs47JSGDhhLKDUh1UMipwwinMYPTBuIBjEclSaGZUk9hDlTb5sUTYN2SFFQuPe4Gox1X0FZOufjgBiV1Vls7b+GvK3SU4wfmcGo9rPPQzgIabfj4TYQo15k3bTHX9RIw/kniir5YbtJF4jkFG+dsDK1IgE413zAthU/vR2HVMmFUPIHTvF6jWCpFaGw/A3qWgnbxpSm9MSmY5b3pM1gvNc/gQfwBsGwF0VCtxZgAAAAASUVORK5CYII= Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > So in first iteration, interrupt is cleared, and in second, function will execute: > > } else if (end == NULL) > end = l; > > which will terminate the loop, but the return code will be IRQ_RETVAL(0). If you are getting an extra IRQ when then chip itself is indicating no IRQ then the IRQ is spurious. That probably means you have a problem elsewhere - eg the IRQ controller being misconfigured between level/edge triggered. Alan