From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932210AbWDRLmv (ORCPT ); Tue, 18 Apr 2006 07:42:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932206AbWDRLmu (ORCPT ); Tue, 18 Apr 2006 07:42:50 -0400 Received: from outpipe-village-512-1.bc.nu ([81.2.110.250]:33162 "EHLO lxorguk.ukuu.org.uk") by vger.kernel.org with ESMTP id S932205AbWDRLmu (ORCPT ); Tue, 18 Apr 2006 07:42:50 -0400 Subject: Re: [PATCH 1/1] ide: Allow disabling of UDMA for Compact Flash devices From: Alan Cox To: Andreas Mohr Cc: James Ausmus , Bartlomiej Zolnierkiewicz , linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org In-Reply-To: <20060418113439.GA11815@rhlx01.fht-esslingen.de> References: <1145358858.18736.16.camel@localhost.localdomain> <20060418113439.GA11815@rhlx01.fht-esslingen.de> Content-Type: text/plain Content-Transfer-Encoding: 7bit Date: Tue, 18 Apr 2006 12:52:33 +0100 Message-Id: <1145361153.18736.36.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 (2.2.3-2.fc4) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Maw, 2006-04-18 at 13:34 +0200, Andreas Mohr wrote: > However, while this is much better than a compile-time setting, it's still > not fully satisfying since many users won't realize that they're hitting this > problem and thus won't search for and find this obscure boot parameter. > Is there any way at all to get this condition detected automatically? Not that I can think off immediately. The controller and the drive both report the modes they support. If that is wrong then we either need to be able to identify the specific device (as libata does with the Palmax systems) or try it and see (which we indeed do but takes time to error out). For PCMCIA CF adapters we are ok because they are ISA bus so PIO 0 cycles are all that are supported. For other controllers it will depend whether the CF adapter is integrated into a PCI card with unique subvendor/dev identifiers which can be blacklisted, or a motherboard with DMI entries that can be used. If it's just some poorly engineered 'shove a cable in one end and a CF card the other' device which is therefore not directly detectable I think you lose. Alan