Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752122AbYLNSxT (ORCPT ); Sun, 14 Dec 2008 13:53:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750945AbYLNSxF (ORCPT ); Sun, 14 Dec 2008 13:53:05 -0500 Received: from colo.lackof.org ([198.49.126.79]:55108 "EHLO colo.lackof.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750914AbYLNSxE (ORCPT ); Sun, 14 Dec 2008 13:53:04 -0500 Date: Sun, 14 Dec 2008 11:52:39 -0700 From: Grant Grundler To: Manu Abraham Cc: Grant Grundler , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org Subject: Re: MSI messages Message-ID: <20081214185239.GA2039@colo.lackof.org> References: <49438290.1080502@gmail.com> <20081214081210.GC13371@colo.lackof.org> <4944EAC3.1020407@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4944EAC3.1020407@gmail.com> X-Home-Page: http://www.parisc-linux.org/ User-Agent: Mutt/1.5.16 (2007-06-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1425 Lines: 33 On Sun, Dec 14, 2008 at 03:15:15PM +0400, Manu Abraham wrote: ... > > A "GSI" (Generic Sys Interrupt?) is associated with each entry in > > the MSI-X table. Driver then calls request_irq() to bind an interrupt > > handler to each GSI. So the driver never directly sees the "message". > > Oh, you mean the array of irq_handlers in the MSI-X table should > correspond to a particular message ? No. I mean each MSI-X entry has an address+message pair and each MSI-X entry is associated with the parameters passed to each call of request_irq(). Pass in unique private data to each call of request_irq() and the driver can determine which message was delivered when the ISR gets called. (ISR == Interrupt Service Routine, aka driver IRQ handler) > I remember sometime back somebody stated that one might not get > the requested number of handlers what you requested. Correct. The limit is defined by the number of GSI's available from the HW. > In such a case, if the irq_handlers are mapped in a static fashion, one > might not get any interrupt callbacks for a specific functionality of > the hardware. Or is there something missing in what i understood ? Correct. grant -- 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/