From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261763AbUGLTIS (ORCPT ); Mon, 12 Jul 2004 15:08:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261184AbUGLTIR (ORCPT ); Mon, 12 Jul 2004 15:08:17 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:7142 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S261763AbUGLTIP (ORCPT ); Mon, 12 Jul 2004 15:08:15 -0400 Date: Mon, 12 Jul 2004 11:03:09 -0300 From: Marcelo Tosatti To: linux-kernel@vger.kernel.org Subject: Re: parport - interrupt sharing possible? Message-ID: <20040712140309.GA3755@logos.cnet> References: <20040712035119.GA1865@dbz.icequake.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040712035119.GA1865@dbz.icequake.net> User-Agent: Mutt/1.5.5.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jul 11, 2004 at 10:51:19PM -0500, Ryan Underwood wrote: > > Hi, > > Does anyone know if the generic parport interrupt handler is okay (or not) > for sharing interrupts? The reason I ask is that I have a PCI parallel > card with two ports on it. Without a IRQ sharing capability, it is not > possible for both of them to operate in interrupt-driven mode. I tested > a quick hack to enable IRQ sharing: > http://home.icequake.net/~nemesis/parport.diff > > and it seems to work okay with both ports in use. I'm hoping someone > more knowledgeable on the parallel port subject (Tim Waugh?) can shed > some light on whether this is acceptable or not. The interrupt handler > eventually ends up in parport_ieee1284_interrupt which really doesn't do > much besides wake up sleepers. > > Thanks! > > PS: Heh, the power just went out and back on as I wrote this. Giving thanks > for having multiple UPS units around! Hi Ryan, Quoting Tim Waugh: > 2) Allows PCI parallel port to share an IRQ if possible. In limited testing > this seems to be ok, but maybe the interrupt handler was not written for > sharing. Someone else will need to ok this. This seems dangerous to me. There are some issues with IRQs in parport, although I think they are known and there is a fix around: http://lists.infradead.org/pipermail/linux-parport/2004-March/000048.html Incidentally, I have asked if there is anyone with more time than me who would like to maintain the paride/parport bits, but no-one has stepped forward. I see that Al Viro has fixed a lot of problems while I've been busy with other things.