From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759993AbXGVOq2 (ORCPT ); Sun, 22 Jul 2007 10:46:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752189AbXGVOqU (ORCPT ); Sun, 22 Jul 2007 10:46:20 -0400 Received: from outpipe-village-512-1.bc.nu ([81.2.110.250]:33101 "EHLO the-village.bc.nu" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1752020AbXGVOqT (ORCPT ); Sun, 22 Jul 2007 10:46:19 -0400 Date: Sun, 22 Jul 2007 15:53:10 +0100 From: Alan Cox To: "treul" Cc: linux-kernel@vger.kernel.org Subject: Re: dma hardware underrun Message-ID: <20070722155310.47f98ca4@the-village.bc.nu> In-Reply-To: References: X-Mailer: Claws Mail 2.9.1 (GTK+ 2.10.13; i386-redhat-linux-gnu) Organization: Red Hat UK Cyf., Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, Y Deyrnas Gyfunol. Cofrestrwyd yng Nghymru a Lloegr o'r rhif cofrestru 3798903 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 > My debugging result shows the underrun goes away if I put 2 printf's in the > harddisk ISR. The printf is at milli-seconds whereas the duration of the > original ISR is at lower magnitude. In addition, I find a SATA-PCI harddisk > does not have the underrun problem. IDE-PCI device gets the trouble. Is the SATA controller on the motherboard and the PATA one on the PCI bus ? > So, do you have any idea about where the root cause can be hiding? Or what > do you think of adding printf's in ISR? (performance? incurring other > problems by disabling interrupt too long? On a standard PCI bus an IDE DMA disk can saturate the bus. That may be your underlying problem ?