From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH] sata_rcar: clear STOP bit in bmdma_start() method Date: Wed, 22 May 2013 08:41:28 +0900 Message-ID: <20130521234128.GD6985@mtj.dyndns.org> References: <201305212307.55385.sergei.shtylyov@cogentembedded.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pa0-f45.google.com ([209.85.220.45]:65420 "EHLO mail-pa0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752576Ab3EUXlc (ORCPT ); Tue, 21 May 2013 19:41:32 -0400 Received: by mail-pa0-f45.google.com with SMTP id lj1so1210917pab.32 for ; Tue, 21 May 2013 16:41:32 -0700 (PDT) Content-Disposition: inline In-Reply-To: <201305212307.55385.sergei.shtylyov@cogentembedded.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Sergei Shtylyov Cc: linux-ide@vger.kernel.org, vladimir.barinov@cogentembedded.com On Tue, May 21, 2013 at 11:07:54PM +0400, Sergei Shtylyov wrote: > Iff bmdma_setup() has to stop a DMA transfer before starting a new one, then the > STOP bit in the ATAPI_CONTROL1 register will remain set (it's only cleared when > setting the START bit to 1) and then bmdma_start() method will set both START > and STOP bits simultaneously which should abort the transfer being just started. > Avoid that by explicitly clearing the STOP bit in bmdma_start() method (in this > case it will be ignored on write). > > Signed-off-by: Sergei Shtylyov Applied to libata/for-3.10-fixes w/ stable cc'd. Thanks. -- tejun