From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751690AbeECQaj (ORCPT ); Thu, 3 May 2018 12:30:39 -0400 Received: from mga05.intel.com ([192.55.52.43]:21599 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751419AbeECQaf (ORCPT ); Thu, 3 May 2018 12:30:35 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.49,359,1520924400"; d="scan'208";a="225557884" Date: Thu, 3 May 2018 22:05:22 +0530 From: Vinod Koul To: Frank Mori Hess Cc: Vinod Koul , dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, Dan Williams , r.baldyga@hackerion.com Subject: Re: [PATCH] Revert "dmaengine: pl330: add DMA_PAUSE feature" Message-ID: <20180503163521.GZ6014@localhost> References: <2484918.HKVQc3yJkt@bear> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2484918.HKVQc3yJkt@bear> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Apr 28, 2018 at 05:50:58PM -0400, Frank Mori Hess wrote: > This reverts commit 88987d2c7534a0269f567fb101e6d71a08f0f01d. > > The pl330.c pause implementation violates the dmaengine requirement > for no data loss, since it relies on the DMAKILL > instruction. However, DMAKILL discards in-flight data from the > dma controller's fifo. This is documented in the dma-330 manual > and I have observed it with hardware doing device-to-memory burst > transfers. The discarded data may or may not show up in the > residue count, depending on timing (resulting in data corruption > effectively). Applied, thanks -- ~Vinod