Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755185AbYKNR7w (ORCPT ); Fri, 14 Nov 2008 12:59:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751700AbYKNR7p (ORCPT ); Fri, 14 Nov 2008 12:59:45 -0500 Received: from www.crouse-house.com ([199.45.160.146]:33730 "EHLO mail.crouse-house.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750918AbYKNR7o (ORCPT ); Fri, 14 Nov 2008 12:59:44 -0500 X-Greylist: delayed 1493 seconds by postgrey-1.27 at vger.kernel.org; Fri, 14 Nov 2008 12:59:44 EST Message-ID: <491DB6B9.7030209@cosmicpenguin.net> Date: Fri, 14 Nov 2008 10:34:49 -0700 From: Jordan Crouse Reply-To: jordan@cosmicpenguin.net User-Agent: Thunderbird 2.0.0.17 (X11/20080925) MIME-Version: 1.0 To: Pavel Machek CC: Andres Salomon , Takashi Iwai , Ingo Molnar , Jeremy Katz , Thomas Gleixner , Jordan Crouse , linux-kernel@vger.kernel.org, dsaxena@laptop.org Subject: Re: [PATCH] ALSA: cs5535audio: only build OLPC support if MGEODE_LX is defined References: <1226547898.13077.83.camel@aglarond.local> <20081113153714.GA1520@ucw.cz> <20081113111428.59aa36cb@ephemeral> <20081113163802.GA1734@ucw.cz> <20081113120147.2ecde3c8@ephemeral> <20081113190339.GE17851@elte.hu> <20081113213852.16561ed2@ephemeral> <20081114075248.GB8397@atrey.karlin.mff.cuni.cz> In-Reply-To: <20081114075248.GB8397@atrey.karlin.mff.cuni.cz> 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 Content-Length: 2847 Lines: 63 Pavel Machek wrote: > HI! > >>>> i've zapped this patch meanwhile: >>>> >>>> 1355c96: x86/olpc: make CONFIG_OLPC dependent on CONFIG_MGEODE_LX >>>> >>>> because it cripples the ability to run distribution kernels on the >>>> OLPC. >>> OK, I reverted also all relevant changes for cs5535audio driver now. >>> The patches are saved in topic/cs5535audio branch, though. >>> >>> Let's fix OLPC-geode coupling first. >> Hm, I'd really rather prefer this to be upstream. The patch I sent adds >> no regressions, allows the driver to happily coexist with existing >> stuff, and *does* add support if you configure OLPC with MGEODE_LX >> (generic kernels don't get the additional benefits, but those configured >> specifically for OLPC do). > > Yes, but the patch is also not a good way of going forward, so it > should not be in mainline. For the moment, this is a reasonable intermediate solution. I think the way forward will involve a great deal more work. The driver does need to be able to twiddle the GPIO pins, and the GPIO pins are unique to the CS5536. In the past, the CS5536 has been only associated with the Geode, and 99.99% of the kernel users in the world don't need Geode, so it make sense to omit specific code of this nature. As you might expect, I'm not in the "you should be able to run an arbitrary kernel on the XO" crowd. That said, its clear that people are interested in doing so - so a change needs to be made. The immediate option is to turn on Geode support for all x86 kernels, but thats a few extra K in the kernel binary that nobody needs. So we'll have to go modular. I talked to Andres about this yesterday. The immediately obvious solution would be to port the Geode GPIO support into the existing GPIO subsystem. That is attractive, but it omits some of the other Geode goodness that might be of interest to a "standard kernel" not configured for MGEODE_LX (such as the Geode watchdog timer). So, I think we should move most of the Geode code into a support module and remove MGEODE_LX checks in most places. The distributions can build the module and put it in the file system, and serious Geode users such as OLPC can build it in to the kernel binary. Also, while we are at it, we should be more specific and rename the hooks from geode_ to cs5536_, since there will soon be a system in the wild with a MIPS processor and a CS5536. But needless to say, this will be a goodly amount of work and churn that will need some heavy testing in the OLPC kernel. In the meantime, Andres' fix will make the upstream kernel happier. Jordan -- 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/