From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754702Ab3JVXrK (ORCPT ); Tue, 22 Oct 2013 19:47:10 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:38565 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754314Ab3JVXrJ (ORCPT ); Tue, 22 Oct 2013 19:47:09 -0400 Date: Wed, 23 Oct 2013 00:48:35 +0100 From: Greg Kroah-Hartman To: Bin Gao Cc: Guenter Roeck , Arnd Bergmann , linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/4] drivers/misc: add rawio framework and drivers Message-ID: <20131022234835.GB12031@kroah.com> References: <5265C0C5.70905@linux.intel.com> <20131022054406.GA14163@kroah.com> <20131022171400.GA14558@roeck-us.net> <20131022185004.GC53231@bingao-desk1.fm.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131022185004.GC53231@bingao-desk1.fm.intel.com> User-Agent: Mutt/1.5.22 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 22, 2013 at 11:50:04AM -0700, Bin Gao wrote: > On Tue, Oct 22, 2013 at 10:14:00AM -0700, Guenter Roeck wrote: > > > > > > You can already do this today for PCI with the UIO framework, right? > > > Why duplicate that functionality here with another userapce API that we > > > will then have to maintain for the next 40+ years? > > > > > Same for i2c, where the same functionality is supported through i2c-tools and > > the i2c-dev driver. Adding i2c-tools to initramfs and/or to the root file system > > should not be that much of an issue, much less than having to maintain two APIs > > for the same purpose. > > > > Guenter > > For PCI and memory mapped I/O devices, we have the runtime pm issue that has to > be addressed from kernel space. Then create a UIO pci driver and you should be fine, right? That's what others do today and it works quite well for them. greg k-h