Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261500AbTELSfc (ORCPT ); Mon, 12 May 2003 14:35:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262416AbTELSfc (ORCPT ); Mon, 12 May 2003 14:35:32 -0400 Received: from notes.hallinto.turkuamk.fi ([195.148.215.149]:22284 "EHLO notes.hallinto.turkuamk.fi") by vger.kernel.org with ESMTP id S261500AbTELSfb (ORCPT ); Mon, 12 May 2003 14:35:31 -0400 Message-ID: <3EBFEDD1.2060904@kolumbus.fi> Date: Mon, 12 May 2003 21:54:09 +0300 From: =?ISO-8859-1?Q?Mika_Penttil=E4?= User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.2) Gecko/20030208 Netscape/7.02 X-Accept-Language: en-us, en MIME-Version: 1.0 To: "David S. Miller" CC: willy@debian.org, jgarzik@pobox.com, linux-kernel@vger.kernel.org, ink@jurassic.park.msu.ru Subject: Re: Message Signalled Interrupt support? References: <20030512163249.GF27111@gtf.org> <20030512165331.GZ29534@parcelfarce.linux.theplanet.co.uk> <20030512.102023.71099561.davem@redhat.com> X-MIMETrack: Itemize by SMTP Server on marconi.hallinto.turkuamk.fi/TAMK(Release 5.0.8 |June 18, 2001) at 12.05.2003 21:49:18, Serialize by Router on notes.hallinto.turkuamk.fi/TAMK(Release 5.0.10 |March 22, 2002) at 12.05.2003 21:48:53, Serialize complete at 12.05.2003 21:48:53 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=us-ascii; format=flowed Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1639 Lines: 42 I think that MSI should be made quite explicit. If the device and platform both support MSI, then the driver should be able to ask for MSI, but kernel must be able to deny it. All devices supporting MSI must support also pin based interrupt delivery. As MSI can be costy (one interrupt vector per device for instance), it could be that a device has to work in pin based mode instead. --Mika David S. Miller wrote: > From: Matthew Wilcox > Date: Mon, 12 May 2003 17:53:31 +0100 > > On Mon, May 12, 2003 at 12:32:49PM -0400, Jeff Garzik wrote: > > Has anybody done any work, or put any thought, into MSI support? > > Work -- no. Thought? A little. Seems to me that MSIs need to be > treated as a third form of interrupts (level/edge/message). > >The fact that Alpha already supports them pretty much transparently >suggests that the thing to do might very well be "nothing" :-) > >To be honest, MSIs are very similar to how interrupts work on sparc64, >in that each device generates a unique interrupt cookie. The only >different is the size of this cookie, MSIs are larger than sparc64's. >- >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/ > > > - 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/