From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752689AbbJFLPR (ORCPT ); Tue, 6 Oct 2015 07:15:17 -0400 Received: from e06smtp16.uk.ibm.com ([195.75.94.112]:37130 "EHLO e06smtp16.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752578AbbJFLPO (ORCPT ); Tue, 6 Oct 2015 07:15:14 -0400 X-IBM-Helo: d06dlp01.portsmouth.uk.ibm.com X-IBM-MailFrom: schwidefsky@de.ibm.com X-IBM-RcptTo: linux-arch@vger.kernel.org;linux-kernel@vger.kernel.org;linux-s390@vger.kernel.org Date: Tue, 6 Oct 2015 13:15:04 +0200 From: Martin Schwidefsky To: "Luis R. Rodriguez" Cc: Arnd Bergmann , "Luis R. Rodriguez" , linux-arch@vger.kernel.org, mingo@kernel.org, heiko.carstens@de.ibm.com, linux-s390@vger.kernel.org, bp@suse.de, linux@roeck-us.net, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, rostedt@goodmis.org Subject: Re: [RFC] asm-generic/pci_iomap.h: make custom PCI BAR requirements explicit Message-ID: <20151006131504.4385c598@mschwide> In-Reply-To: <20151005170914.GM14464@wotan.suse.de> References: <1440807447-584-1-git-send-email-mcgrof@do-not-panic.com> <1866509.8pE0MIz57e@wuerfel> <20151002235346.GJ14464@wotan.suse.de> <8902671.32Mbh7QhE4@wuerfel> <20151005170914.GM14464@wotan.suse.de> X-Mailer: Claws Mail 3.9.3 (GTK+ 2.24.23; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15100611-0025-0000-0000-0000073756EB Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 5 Oct 2015 19:09:14 +0200 "Luis R. Rodriguez" wrote: > On Sun, Oct 04, 2015 at 09:02:04PM +0200, Arnd Bergmann wrote: > > On Saturday 03 October 2015 01:53:46 Luis R. Rodriguez wrote: > > > > > > > > Hmm, my gut feeling tells me that your approach won't solve the problem > > > > in general. s390 PCI is just weird in many ways and it will occasionally > > > > suffer from problems like this (as do other aspects of the s390 architecture > > > > that are unlike the rest of the world). > > > > > > > > Maybe Martin and Heiko can comment on this, they may have a preference > > > > from the s390 point of view. > > > > > > Hrm, so S390 is quirky is really odd ways that no other architecture is or > > > is at least for now not expected to be ? > > > > Absolutely correct. It is the only architecture I'm aware of that tries to > > support PCI that does not use pointer dereferences for MMIO. > > So its not worth it to have a formal semantic via Kconfig for this and are > happy with the status quo of having to find out through a bot compile test > any changes in this domain fails? For my part I still do not see the value in ARCH_PCI_NON_DISJUNCTIVE. The existing GENERIC_PCI_IOMAP already allows an architecture to select the generic implementation (or not to select it). To add another Kconfig symbol and make GENERIC_PCI_IOMAP depend on it doesn't help. -- blue skies, Martin. "Reality continues to ruin my life." - Calvin.