From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Evert van Grootheest Subject: Re: [PATCH ht6560b] Force prefetch for some devices Date: Mon, 18 Feb 2008 16:21:01 +0100 Message-ID: <47B9A25D.4020107@caiway.nl> References: <47B97EFA.2040805@caiway.nl> <20080218143636.3394eece@core> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from pelian.kabelfoon.nl ([62.45.45.43]:50465 "EHLO pelian.kabelfoon.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753728AbYBRPVD (ORCPT ); Mon, 18 Feb 2008 10:21:03 -0500 In-Reply-To: <20080218143636.3394eece@core> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Alan Cox Cc: linux-ide@vger.kernel.org, bzolnier@gmail.com Alan, Alan Cox wrote: > On Mon, 18 Feb 2008 13:50:02 +0100 > Jan Evert van Grootheest wrote: > > >> Prefetch needs to be set for some ide devices to work when connected to >> a ht6560b interface. This was not always done properly, causing a system >> with a HD and CD on the primary interface to not work properly. Or, in >> effect, hang hard. >> >> This patch forces prefetch on devices before checking whether it >> is necessary to change the settings in the interface >> > > Interesting, that is backwards to the docs and not something I've seen. > Hum, I may have an incorrect understanding of the prefetch bit or misread the code. But for sure that patch makes my 486 boot (HD as primary master and CD as primary slave). From testing I know that the HD works with and without prefetch (it's 1.15M/s without prefetch, ~950k/s with). And the boot hangs (as in powerbutton required) if prefetch is not set for the CD. For reference, the generic IDE driver is ~850k/s. > If you are correct then pata_legacy also wants tweaking . > > Alan > I think, but didn't look real good nor test yet, that pata_legacy also needs something comparable to select_proc? Or is that implemented in some generic manner? Depending on the day job, I could get to testing that somewhere this week. -- Jan Evert