From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vinod Koul Subject: Re: [PATCH 1/1] dma: edma: fix incorrect SG list handling Date: Mon, 14 Apr 2014 14:27:46 +0530 Message-ID: <20140414085746.GG32284@intel.com> References: <1395208550-1603-1-git-send-email-nsekhar@ti.com> <534B9CCF.1070904@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mga09.intel.com ([134.134.136.24]:28594 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752140AbaDNJHh (ORCPT ); Mon, 14 Apr 2014 05:07:37 -0400 Content-Disposition: inline In-Reply-To: <534B9CCF.1070904@ti.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Sekhar Nori Cc: Dan Williams , DMA Engine Mailing List , Linux DaVinci Mailing List , Jon Ringle , Alexander Holler , Linux OMAP Mailing List , Joel Fernandes On Mon, Apr 14, 2014 at 02:01:11PM +0530, Sekhar Nori wrote: > Vinod, > > On Wednesday 19 March 2014 11:25 AM, Sekhar Nori wrote: > > The code to handle any length SG lists calls edma_resume() > > even before edma_start() is called. This is incorrect > > because edma_resume() enables edma events on the channel > > after which CPU (in edma_start) cannot clear posted > > events by writing to ECR (per the EDMA user's guide). > > > > Because of this EDMA transfers fail to start if due > > to some reason there is a pending EDMA event registered > > even before EDMA transfers are started. This can happen if > > an EDMA event is a byproduct of device initialization. > > > > Fix this by calling edma_resume() only if it is not the > > first batch of MAX_NR_SG elements. > > > > Without this patch, MMC/SD fails to function on DA850 EVM > > with DMA. The behaviour is triggered by specific IP and > > this can explain why the issue was not reported before > > (example with MMC/SD on AM335x). > > > > Tested on DA850 EVM and AM335x EVM-SK using MMC/SD card. > > > > Cc: stable@vger.kernel.org # v3.12.x+ > > Cc: Joel Fernandes > > Acked-by: Joel Fernandes > > Tested-by: Jon Ringle > > Tested-by: Alexander Holler > > Reported-by: Jon Ringle > > Signed-off-by: Sekhar Nori > > Looks like this patch is not in mainline still? Sorry looks like I have missed sending the email. I had applied it last week and today rebased after rc1. It would be part of rc2... -- ~Vinod > > Thanks, > Sekhar --