From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [patch 1/2] sata_via: Correctly setup PIO/DMA for pata slave on vt6421. Date: Wed, 20 Jan 2010 12:33:05 +0900 Message-ID: <4B567971.7000904@gmail.com> References: <20100116235653.898098245@gmail.com> <20100116235849.969478053@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-px0-f182.google.com ([209.85.216.182]:39938 "EHLO mail-px0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754890Ab0ATD1C (ORCPT ); Tue, 19 Jan 2010 22:27:02 -0500 In-Reply-To: <20100116235849.969478053@gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Bart Hartgers Cc: linux-kernel@vger.kernel.org, Jeff Garzik , linux-ide@vger.kernel.org On 01/17/2010 08:56 AM, Bart Hartgers wrote: > Before only the timings for master were set. Datasheet can be found > here: ftp://ftp.vtbridge.org/Docs/Storage/DS_VT6421A_100_CCPL.PDF > Surprisingly, a slave drive works without this patch. According to the > datasheet, the controller by default derives the DMA mode from the > Set Features command issued to a drive. Not sure about the PIO > timings, though. The real problem is that the timings for the master > effectively are the ones tuned for the slave. If these support > different UDMA-settings, there is trouble, especially when the slave > supports a higher UDMA than the master. > > Anyhow, using the same mechanism for both master and slave seems like > a good idea. > > Signed-off-by: Bart Hartgers Acked-by: Tejun Heo Thanks. -- tejun