From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: [GIT PULL] omap changes for v2.6.39 merge window Date: Fri, 01 Apr 2011 14:10:04 -0700 Message-ID: <87vcyxllub.fsf@ti.com> References: <201104011554.07924.arnd@arndb.de> <4D95E112.4020400@vollmann.ch> <201104011659.40443.arnd@arndb.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: In-Reply-To: <201104011659.40443.arnd@arndb.de> (Arnd Bergmann's message of "Fri, 1 Apr 2011 16:59:40 +0200") Sender: linux-kernel-owner@vger.kernel.org To: Arnd Bergmann Cc: Detlef Vollmann , Ingo Molnar , david@lang.hm, Russell King - ARM Linux , Nicolas Pitre , Tony Lindgren , Catalin Marinas , lkml , "H. Peter Anvin" , David Brown , linux-omap@vger.kernel.org, Linus Torvalds , Thomas Gleixner , linux-arm-kernel@lists.infradead.org List-Id: linux-omap@vger.kernel.org Arnd Bergmann writes: > On Friday 01 April 2011, Detlef Vollmann wrote: >> On 04/01/11 15:54, Arnd Bergmann wrote: > >> > 9. All interesting work is going into a handful of platforms, all of which >> > are ARMv7 based. >> Define interesting. > > The ones that are causing the churn that we're talking about. > Platforms that have been working forever and only need to get > the occasional bug fix are boring, i.e. not the problem. I'm not sure I follow the ARMv7-only thinking either. Picking ARMv7 only would be a good way to avoid part of the problem, but IMO, it doesn't really address the root causes. Part of the ugliness of the platform-specific hackery (and the "churn" to clean some of it up) is precisely due to support for multiple ARM architecture versions, and the various SoCs in a family that use them. For example, linux-omap supports OMAP1 (ARMv5), OMAP2 (ARMv6), OMAP3 (ARMv7) and OMAP4 (ARMv7 SMP), and OMAP2/3/4 in a single binary. Also, since we've only very recently got to the point of being able to support ARMv6 + ARMv7 UP & SMP in the same kernel, making a decision now that only ARMv7 is important seems like a step backwards. If the ultimate goal is getting to a point where we have infrastrucure that can be cross-SoC, surely this same infrastrucure should support multiple ARM architecture revisions. The kernel is only part of many open-source projects, and many of these projects are still using older hardware because it's cheap, available and hackable. Supporting ARMv7 only might be a win for those selling new hardware, but not necessarily a win for the broader open-source community. Kevin (obviously not speaking for my new employer)