Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S270816AbTHLRcn (ORCPT ); Tue, 12 Aug 2003 13:32:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S270818AbTHLRcn (ORCPT ); Tue, 12 Aug 2003 13:32:43 -0400 Received: from fmr06.intel.com ([134.134.136.7]:58581 "EHLO caduceus.jf.intel.com") by vger.kernel.org with ESMTP id S270816AbTHLRcm convert rfc822-to-8bit (ORCPT ); Tue, 12 Aug 2003 13:32:42 -0400 Content-Class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-MimeOLE: Produced By Microsoft Exchange V6.0.6375.0 Subject: RE: Updated MSI Patches Date: Tue, 12 Aug 2003 10:32:39 -0700 Message-ID: X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: Updated MSI Patches Thread-Index: AcNgdINGIzr3UbJrQb6ybAY+0LD/YwAgq6Tw From: "Nguyen, Tom L" To: "Zwane Mwaikambo" , "Greg KH" Cc: "long" , "Nakajima, Jun" , X-OriginalArrivalTime: 12 Aug 2003 17:32:40.0087 (UTC) FILETIME=[BAA1F270:01C360F7] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1601 Lines: 30 > > There are two types of MSI capable devices: one supports the MSI > > capability structure and other supports the MSI-X capability structure. > > The patches provide two APIs msix_alloc_vectors/msix_free_vectors for > > only devices, which support the MSI-X capability structure, to request > > for additional messages. By default, each MSI/MSI-X capable device > > function is allocated with one vector for below reasons: > > - To achieve a backward compatibility with existing drivers if possible. > > - Due to the current implementation of vector assignment, all devices > > that support the MSI-capability structure work with no more than one > > allocated vector. > > - The hardware devices, which support the MSI-X capability structure, > > may indicate the maximum capable number of vectors supported (32 > > vectors as example). However, the device drivers may require only > > four. With provided APIs, the optimization of MSI vector allocation > > is achievable. > IMO Multiplexing would be preferred, we can't be allocating that many > vectors for one device/device driver All pre-assigned vectors to all enabled IOxAPIC(s) are reserved. Allocating additional vectors to MSI-X driver is determined based on the available vectors, which must be greater than the number of vectors requested by MSI-X driver. Thanks, Long - 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/