Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752953AbZI2RE7 (ORCPT ); Tue, 29 Sep 2009 13:04:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752294AbZI2RE7 (ORCPT ); Tue, 29 Sep 2009 13:04:59 -0400 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:56603 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751609AbZI2RE6 (ORCPT ); Tue, 29 Sep 2009 13:04:58 -0400 Date: Tue, 29 Sep 2009 18:05:55 +0100 From: Alan Cox To: Krzysztof Halasa Cc: Arjan van de Ven , "Lennart Baruschka" , linux-kernel@vger.kernel.org Subject: Re: Disabling DMA with ICH10? Message-ID: <20090929180555.3c4a7259@lxorguk.ukuu.org.uk> In-Reply-To: References: <1254173481.4454.32.camel@goodbyte.homelinux.com> <20090928234025.6dc4e3f7@lxorguk.ukuu.org.uk> <20090929075416.77960@gmx.net> <20090929101114.1712314b@infradead.org> X-Mailer: Claws Mail 3.7.2 (GTK+ 2.14.7; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 857 Lines: 21 On Tue, 29 Sep 2009 14:29:27 +0200 Krzysztof Halasa wrote: > Arjan van de Ven writes: > > > a single PIO instruction will NOT be interrupted by an interrupt. > > And can easily take several microseconds (remember: 8Mhz bus > > emulation) > > Not that long, there is no emulation there (except for port #80 (hex?) > and similar). Normal 33 MHz access. ATA accesses go across the cable and while some of them are snooped, cached and other magic is done there are cases it turns into a transaction back and forth with the drive - that *is* slow. PIO 0 in fact is ISA speed -- 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/