From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Wed, 21 Jan 2009 06:49:00 +0000 (GMT) Received: from fnoeppeil36.netpark.at ([217.175.205.164]:47514 "EHLO roarinelk.homelinux.net") by ftp.linux-mips.org with ESMTP id S21365687AbZAUGs6 (ORCPT ); Wed, 21 Jan 2009 06:48:58 +0000 Received: (qmail 27110 invoked by uid 1000); 21 Jan 2009 07:48:56 +0100 Date: Wed, 21 Jan 2009 07:48:56 +0100 From: Manuel Lauss To: Kevin Hickey Cc: Ralf Baechle , Linux-MIPS Subject: Re: [PATCH] Alchemy: fix edge irq handling Message-ID: <20090121064856.GA27020@roarinelk.homelinux.net> References: <20090120100353.GA18971@roarinelk.homelinux.net> <1232498838.3678.17.camel@kh-d820> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1232498838.3678.17.camel@kh-d820> User-Agent: Mutt/1.5.16 (2007-06-09) Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 21793 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: mano@roarinelk.homelinux.net Precedence: bulk X-list: linux-mips Hi Kevin, > Have you actually seen this happen (outside of inducing it manually)? I > have some concern that by doing this we may either miss interrupts on > devices that send a lot (by design) or miss a design bug in a system > because we are masking out some interrupts. I know that system > stability is important, but I don't like hiding problems. Yes, in a customer project. A simple pushbutton which connects a pulled-up gpio pin to ground. Push it, instant hang (handler called over and over again) when it is not debounced. With a single edge and a much lower edge-frequency it obviously works fine (see timer). (And, handle_edge_irq() _does_ call mask_ack() after all). Best regards, Manuel Lauss > =Kevin > > On Tue, 2009-01-20 at 11:03 +0100, Manuel Lauss wrote: > > Introduce separate mack_ack callbacks which really do shut up the > > edge-triggered irqs when called. Without this change, high-frequency > > edge interrupts can result in an endless irq storm, hanging the system. > > > > This can be easily triggered for example by setting an irq to falling > > edge type and manually connecting the associated pin to ground. > >