Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765560AbXEVRT4 (ORCPT ); Tue, 22 May 2007 13:19:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756747AbXEVRTs (ORCPT ); Tue, 22 May 2007 13:19:48 -0400 Received: from smtp.osdl.org ([207.189.120.12]:44275 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754973AbXEVRTr (ORCPT ); Tue, 22 May 2007 13:19:47 -0400 Date: Tue, 22 May 2007 10:19:26 -0700 From: Stephen Hemminger To: Linus Torvalds Cc: Jeff Garzik , Mike Houston , Linux Kernel Mailing List Subject: Re: Linux 2.6.22-rc2 Message-ID: <20070522101926.481d3ec7@freepuppy> In-Reply-To: References: <20070520170506.814a38d9.mikeserv@bmts.com> <20070521084549.61a1aa71@freepuppy> <20070521131055.0017404f.mikeserv@bmts.com> <20070521103755.51b954e1@freepuppy> <20070521225806.bb18d589.mikeserv@bmts.com> <20070521213146.3e220a44@freepuppy> <4652733F.4030708@garzik.org> <20070521214255.3dc36445@freepuppy> Organization: Linux Foundation X-Mailer: Sylpheed-Claws 2.6.0 (GTK+ 2.10.11; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1324 Lines: 36 On Mon, 21 May 2007 22:04:26 -0700 (PDT) Linus Torvalds wrote: > > > On Mon, 21 May 2007, Stephen Hemminger wrote: > > > > AHCI on this motherboard doesn't seem to use MSI. The problems occur > > even if I boot with nomsi. > > Have you tried playing with PCI latency counters etc? > > Maybe the SATA/AHCI thing is better at saturating the bus, and the sky2 > hardware gets upset if it has overlong DMA access latencies due to some > other controller keeping the bus busy with a long burst access? > > I can't really see that being a real problem in this day and age of PCI-X > etc, but it _used_ to be a possible issue a decade ago. Maybe you've found > a case where it matters even on modern hardware? We occasionally used to > set the PCI latency timer to make people happy. > > (Not that I'm convinced it even has any semantic meaning on a modern PCI > system..) > > Linus The device in question is PCI Express, and the latency has no meaning (at least in vendor spec). -- Stephen Hemminger - 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/