From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.genesi-usa.com (mithrandir.softwarenexus.net [66.98.186.96]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id 54DFDDDDF4 for ; Mon, 8 Jan 2007 09:11:05 +1100 (EST) Message-ID: <45A16FF1.5000401@genesi-usa.com> Date: Sun, 07 Jan 2007 22:10:57 +0000 From: Matt Sealey MIME-Version: 1.0 To: Segher Boessenkool Subject: Re: [PATCH] Probe Efika platform before CHRP. References: <17799.34168.811328.653008@cargo.ozlabs.ibm.com> <1166528379.19254.69.camel@localhost.localdomain> <4587D338.7060906@246tNt.com> <1166538553.25827.99.camel@pmac.infradead.org> <1166558300.19254.71.camel@localhost.localdomain> <1167773388.22068.443.camel@pmac.infradead.org> <1167773863.6165.82.camel@localhost.localdomain> <1167775493.3660.23.camel@shinybook.infradead.org> <528646bc0701021504k88682bl765fad4c100bd40e@mail.gmail.com> <45A01416.6080401@genesi-usa.com> <528646bc0701061423o270df3dfj9d27d5572840ec79@mail.gmail.com> <45A1535C.1080007@genesi-usa.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Cc: David Woodhouse , bbrv@genesi-usa.com, Paul Mackerras , Linux PPC DEV List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Why is it so funny? I'd love to be enlightened rather than just plain insulted about it. I don't think any of that can be taken into account by simply giving things *names* and then having a 3-week discussion and committee hearing about how someone gave it a DIFFERENT name. It is even more strange to me, that nobody HAS a standard name for the devices on the MPC5200B, yet we are arguing about what would look nicer in the Linux source code? Small example: mpc5200b-fec, mpc5200-fec, mpc52xx-fec doesn't tell you anything, and then with the 5500 or 5120 or something, you then have worked out you named your original devices wrong, and now need to make it compatible with those? Do you switch features on and off based on a string comparison? What if a certain chip revision has a bug you need to work around (there are plenty in the original MPC5200!), is that meant to be encoded in the "compatible" property too, somehow? Or would you check the SVR too? If you would check that, why not use this as the basis of the support for that driver? For a PCI device, you are given basically a 32-bit UID for each device, which is attached to a unique domain, host, bus, device and function number. You manage well here without giving it names. An Intel processor might return a string for CPUID - mine says it's a "Intel(R) Pentium(R) M 1.70GHz". That string is absolutely useless in determining it's compatibility. It's just a name. It may as well say "Fight Famine In Rwanda" for all the good it does. I think there are better ways and better places to encode certain properties of the system as a whole (as the system is a lot more than just that single chip) than having a bunch of strings in a property which claim that it is compatible with something else, strictly defined naming conventions and so on across chip ranges. Although we are talking here mostly about two boards with the same chip basically - Lite5200 and Efika, there may be more boards with similar hardware supported, extra hardware supported, new chips which look very much like the 5200 but have slightly different or bugfixed operation (and here is my point) which I do not think you can encode in names and compatibile names. -- Matt Sealey Genesi, Manager, Developer Relations Segher Boessenkool wrote: >> (especially a C-based one, OpenBIOS >> is 90% Forth which is a terrible lock-in) > >> Isn't the e300 PVR and e300 SVR, or any other device identifier on the >> chip, a much better differentiator for drivers, than a named >> compatibility >> flag? > > Only 7 days into the new year, and already we get some great > entries for best-joke-of-2007! Too bad they're factually > incorrect. > > > Segher >