Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933232Ab3JOQRJ (ORCPT ); Tue, 15 Oct 2013 12:17:09 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:51244 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932311Ab3JOQRI (ORCPT ); Tue, 15 Oct 2013 12:17:08 -0400 Date: Tue, 15 Oct 2013 09:17:06 -0700 From: Greg KH To: Dan Williams Cc: Youquan Song , Vinod Koul , Youquan Song , andriy.shevchenko@intel.com, mika.westerberg@intel.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] dma: Add interface to calculate data transferred Message-ID: <20131015161706.GA4037@kroah.com> References: <1381527738-9339-1-git-send-email-youquan.song@intel.com> <1381527738-9339-2-git-send-email-youquan.song@intel.com> <20131011133343.GB32689@kroah.com> <20131013152633.GM2954@intel.com> <20131015183142.GA12494@linux-youquan.bj.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1767 Lines: 34 On Tue, Oct 15, 2013 at 08:55:20AM -0700, Dan Williams wrote: > On Tue, Oct 15, 2013 at 11:31 AM, Youquan Song > wrote: > > On Sun, Oct 13, 2013 at 08:56:33PM +0530, Vinod Koul wrote: > >> On Fri, Oct 11, 2013 at 06:33:43AM -0700, Greg KH wrote: > >> > On Fri, Oct 11, 2013 at 05:42:17PM -0400, Youquan Song wrote: > > The issue is that when I using UART to transfer data between to COMs > > which using Designware DMA controller channel. But I check the specific > > DMA channel by "cat /sys/class/dma/dma0chan3/bytes_transferred", but it > > should all "0". I have transferred data by UART port, why its DMA > > channel report "0" bytes transferred? So I guess that it is possible > > the DMA device driver issue or the data does not use the Designware DMA channel > > fro transferred. After check the code, I notice only when the DMA > > channel used by network device driver and it will record how much data has been > > tranferred, why other device driver will not calculate it. Since DMA > > channel is used by other device driver, why only network is specific? since it is > > common interface, the current /sys/class/dma/dma0chan*/bytes_transferred has > > much possibility to mislead the user. > > Yes, and for that reason I think we should delete " > /sys/class/dma/dma0chan*/bytes_transferred" it really serves no useful > purpose besides "is my dma channel working" which can be determined by > other means. Sounds good to me, feel free to send a patch. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/