From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 282B1C433EF for ; Fri, 12 Nov 2021 11:57:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F287360E53 for ; Fri, 12 Nov 2021 11:57:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231172AbhKLMA0 (ORCPT ); Fri, 12 Nov 2021 07:00:26 -0500 Received: from gate.crashing.org ([63.228.1.57]:60907 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231147AbhKLMA0 (ORCPT ); Fri, 12 Nov 2021 07:00:26 -0500 Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 1ACBnjBf016776; Fri, 12 Nov 2021 05:49:45 -0600 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 1ACBnfPp016770; Fri, 12 Nov 2021 05:49:41 -0600 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Fri, 12 Nov 2021 05:49:41 -0600 From: Segher Boessenkool To: Olof Johansson Cc: Marc Zyngier , Jens Axboe , Rob Herring , Lorenzo Pieralisi , "R.T.Dickinson" , Arnd Bergmann , kw@linux.com, "linux-pci@vger.kernel.org" , damien.lemoal@opensource.wdc.com, Darren Stevens , Bjorn Helgaas , mad skateman , Christian Zigotzky , "bhelgaas@google.com >> Bjorn Helgaas" , robert@swiecki.net, Matthew Leaman , linuxppc-dev , Alyssa Rosenzweig , Christian Zigotzky Subject: Re: [PASEMI] Nemo board doesn't recognize any ATA disks with the pci-v5.16 updates Message-ID: <20211112114941.GK614@gate.crashing.org> References: <78308692-02e6-9544-4035-3171a8e1e6d4@xenosoft.de> <20211110184106.GA1251058@bhelgaas> <87sfw3969l.wl-maz@kernel.org> <8cc64c3b-b0c0-fb41-9836-2e5e6a4459d1@xenosoft.de> <87r1bn88rt.wl-maz@kernel.org> <87pmr7803l.wl-maz@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.3i Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Thu, Nov 11, 2021 at 02:21:46PM -0800, Olof Johansson wrote: > On Thu, Nov 11, 2021 at 2:20 AM Marc Zyngier wrote: > > Am I right in understanding that the upstream kernel does not support > > the machine out of the box, and that you actually have to apply out of > > tree patches to make it work? That these patches have to do with the > > IRQ routing? > > To my knowledge that has never been needed -- that the base platform > support is all there. > > This is an old platform, and just like with the power macs, the > devicetree is indeed supplied from firmware, and as such not easily > patchable like with ARM platforms. > > Last time this was an issue (to my memory) was when they enabled > automatic little endian switching in the boot path, that caused some > issues with a (bad) phandle pointer that had gone undiscovered for 10+ > years. > > > If so, I wonder why upstream should revert a patch to work on a system > > that isn't supported upstream the first place. I will still try and > > come up with a solution for you. But asking for the revert of a patch > > on these grounds is not, IMHO, acceptable. Also, please provide these > > patches on the list so that I can help you to some extend (and I mean > > *on the list*, not on a random forum that collects my information). > > Early fixups of DT is the way to go here, if needed -- we do it on > some other platforms. That can happen in-kernel, and keep the new > functionality. For that we'd need to figure out what's actually wrong > with the DT as such right now. Yup. The scheme we have now (copy all info from OF, and then take over everything at once) is not ideal at all, but treating OF systems just like "bare" systems has advantages as well, including making it easier to fix up the device tree if it has problems. This is much superior to changing all consumers (drivers etc.) to deal with the broken device trees, so we should do it much more often :-) Segher