From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932827AbcIAOpX (ORCPT ); Thu, 1 Sep 2016 10:45:23 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:50748 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750841AbcIAOpX (ORCPT ); Thu, 1 Sep 2016 10:45:23 -0400 Date: Thu, 1 Sep 2016 16:45:30 +0200 From: "gregkh@linuxfoundation.org" To: "Yangwei (Yang Wei, Device Chipset Key Technologies Platform Development Dept)" Cc: "labbott@redhat.com" , "sumit.semwal@linaro.org" , "arve@android.com" , "riandrews@android.com" , "devel@driverdev.osuosl.org" , "linux-kernel@vger.kernel.org" , "Zengtao (B)" , "Chenhao (benjamin)" Subject: Re: Cma mem map to cpu address when allocated in ion driver, why do this design? Message-ID: <20160901144530.GC11190@kroah.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.7.0 (2016-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 01, 2016 at 12:46:32PM +0000, Yangwei (Yang Wei, Device Chipset Key Technologies Platform Development Dept) wrote: > Hi all, > > When I review ion code in linux-3.18.y, I find a design that may cause > a problem in our product. In the design, cma mem is allocated via the > interface of dma_alloc_coherent , 3.18 is old and obsolete and isn't supported by the kernel community for anything except bug fixes. I suggest you work with whatever group is forcing you to use this old kernel version as they are the ones that you are paying to support this kernel for you. If you wish to discuss the 4.7 or newer kernel versions, and how ion works there (look in linux-next for the most recent changes in that area), we would be glad to help you out. Best of luck! greg k-h