Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936153AbdGTKUd (ORCPT ); Thu, 20 Jul 2017 06:20:33 -0400 Received: from mail-wm0-f41.google.com ([74.125.82.41]:36046 "EHLO mail-wm0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935032AbdGTKU1 (ORCPT ); Thu, 20 Jul 2017 06:20:27 -0400 Date: Thu, 20 Jul 2017 12:20:22 +0200 From: Ingo Molnar To: Linus Torvalds Cc: Dave Airlie , Peter Jones , the arch/x86 maintainers , Dave Airlie , Bartlomiej Zolnierkiewicz , "linux-fbdev@vger.kernel.org" , Linux Kernel Mailing List , Andrew Lutomirski , Peter Anvin Subject: Re: [PATCH] efifb: allow user to disable write combined mapping. Message-ID: <20170720102022.cwbqlf62nc3eal3f@gmail.com> References: <20170718060909.5280-1-airlied@redhat.com> <20170718143404.omgxrujngj2rhiya@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2659 Lines: 59 * Linus Torvalds wrote: > On Tue, Jul 18, 2017 at 2:21 PM, Dave Airlie wrote: > > > > Oh and just FYI, the machine I've tested this on has an mgag200 server > > graphics card backing the framebuffer, but with just efifb loaded. > > Yeah, it looks like it needs special hardware - and particularly the > kind of garbage hardware that people only have on servers. > > Why do server people continually do absolute sh*t hardware? It's crap, > crap, crap across the board outside the CPU. Nasty and bad hacky stuff > that nobody else would touch with a ten-foot pole, and the "serious > enterprise" people lap it up like it was ambrosia. > > It's not just "graphics is bad anyway since we don't care". It's all > the things they ostensibly _do_ care about too, like the disk and the > fabric infrastructure. Buggy nasty crud. I believe it's crappy for similar reasons why almost all other large scale pieces of human technological infrastructure are crappy if you look deep under the hood: transportation and communication networks, banking systems, manufacturing, you name it. The main reasons are: - Cost of a clean redesign is an order of magnitude higher that the next delta revision, once you have accumulated a few decades of legacy. - The path dependent evolutionary legacies become so ugly after time that most good people will run away from key elements - so there's not enough internal energy to redesign and implement a clean methodology from grounds up. - Even if there are enough good people, the benefits of a clean design are a long term benefit, constantly hindered by short term pricing. - For non-experts it's hard to tell a good, clean redesign from a flashy but fundamentally flawed redesign. Both are expensive and the latter can have disastrous outcomes. - These are high margin businesses, with customers captured by legacies, where you can pass down the costs to customers, which hides the true costs of crap. i.e. typical free market failure due high complexity combined with (very) long price propagation latencies and opaqueness of pricing. I believe the only place where you'll find overall beautiful server hardware as a rule and not as an exception is in satellite technology: when the unit price is in excess of $100m, expected life span is 10-20 years with no on-site maintenance, and it's all running in a fundamentally hostile environment, then clean and robust hardware design is forced at every step by physics. Humanity is certainly able to design beautiful hardware, once all other options are exhausted. Thanks, Ingo