From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759117AbZFQQii (ORCPT ); Wed, 17 Jun 2009 12:38:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758188AbZFQQia (ORCPT ); Wed, 17 Jun 2009 12:38:30 -0400 Received: from mga01.intel.com ([192.55.52.88]:19787 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757642AbZFQQi3 (ORCPT ); Wed, 17 Jun 2009 12:38:29 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.42,238,1243839600"; d="scan'208";a="700232592" Message-ID: <4A391C06.2060302@intel.com> Date: Wed, 17 Jun 2009 09:38:30 -0700 From: Dan Williams User-Agent: Thunderbird 2.0.0.14 (Windows/20080421) MIME-Version: 1.0 To: Dragos Tatulea CC: "linux-kernel@vger.kernel.org" , Octavian Purdila Subject: Re: DMA_ENGINE: can't use it without selecting a dma engine driver References: <20090617005318.1e35ae98@dragos-tp.localdomain> <20090617181204.52981f5f@dragos-tp.localdomain> In-Reply-To: <20090617181204.52981f5f@dragos-tp.localdomain> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dragos Tatulea wrote: > Hi, > >>> Just discovered that it's impossible to select the dma engine >>> without compiling a dma engine driver from the kernel. What if I want to >>> use a different dma engine? >>> >> Create a Kconfig entry for your driver in drivers/dma/Kconfig and have >> it "select DMA_ENGINE". > That's what I want to avoid. The dma engine driver is out of tree. > > What is the rationale behind this? It seems (to me) impossible to have all > such drivers in upstream. It is very straightforward to have all drivers upstream, just send the code [1]. The rationale for this configuration scheme is to turn off a lot of unnecessary code when we know at build time that a dma driver will never be loaded. If you must keep your driver out of tree simply maintain another out of tree patch that allows DMA_ENGINE to be manually enabled. Regards, Dan [1]: http://www.kernel.org/doc/Documentation/SubmittingDrivers