From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [PATCH] sata_rcar: clear STOP bit in bmdma_start() method Date: Thu, 23 May 2013 16:14:40 +0400 Message-ID: <519E0830.2000200@cogentembedded.com> References: <201305212307.55385.sergei.shtylyov@cogentembedded.com> <20130521234128.GD6985@mtj.dyndns.org> <519CC450.6030203@cogentembedded.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-lb0-f178.google.com ([209.85.217.178]:34613 "EHLO mail-lb0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758064Ab3EWMOg (ORCPT ); Thu, 23 May 2013 08:14:36 -0400 Received: by mail-lb0-f178.google.com with SMTP id w10so3314276lbi.9 for ; Thu, 23 May 2013 05:14:35 -0700 (PDT) In-Reply-To: <519CC450.6030203@cogentembedded.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Tejun Heo Cc: linux-ide@vger.kernel.org, vladimir.barinov@cogentembedded.com Hello. On 22-05-2013 17:12, 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, I forgot about -stable. Anyway, it doesn't seem that serious > as bmdma_setup() usually shouldn't abort DMA. Although bmdma_stop() also can stop DMA which is not as improbable (media errors, etc.). I could have wrotten a better changelog. :-/ >> Thanks. WBR, Sergei