From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Subject: Re: [PATCH 0/14] Start coping gsis < 16 that are not isa irqs. Date: Wed, 31 Mar 2010 20:31:39 -0700 Message-ID: References: <1269221770-9667-1-git-send-email-yinghai@kernel.org> <1269221770-9667-3-git-send-email-yinghai@kernel.org> <4BB0EA22.7000004@zytor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from out01.mta.xmission.com ([166.70.13.231]:57050 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751927Ab0DADby (ORCPT ); Wed, 31 Mar 2010 23:31:54 -0400 In-Reply-To: (Len Brown's message of "Wed\, 31 Mar 2010 22\:02\:33 -0400 \(EDT\)") Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Len Brown Cc: "H. Peter Anvin" , Thomas Gleixner , Yinghai Lu , Ingo Molnar , Andrew Morton , Jesse Barnes , linux-kernel@vger.kernel.org, Thomas Renninger , Suresh Siddha , len.brown@intel.com, Tony Luck , Fenghua Yu , linux-acpi@vger.kernel.org, Iranna D Ankad , Gary Hade , Natalie Protasevich Len Brown writes: >> It appears there are a few systems in the wild that use acpi >> interrupt source overrides to report a gsi > 16 is an isa irq. >> >> This breaks all kinds of assumptions I figure any BIOS doing that >> probably should be shot as that is very much not a conservative position. > > You might run into trouble here on the ES7000 -- though I don't know > if anybody is booting a modern kernel on one of those these days. > > IIR, ES7000 treated the bottom 16 as a special case. > When there was an irq shortage, I think they used overrides > to map higher PCI irqs into the empty spots below 16, > but I think to make room for them they may have mapped > some of the ISA irqs to high numbers. Fuzzy memory > on this at the moment... A couple of things. The ES7000 change is trivially safe because despite differences in how the numbers are computed I have made that transform that the es7000 does always apply. I also talked to Natalie about this. I can't be certain about this but from your description, from Natalies memories and from looking at the code. I believe the problem on the ES7000 is exactly what I am fixing in the code. Natalie has threatened to test this on an ES7000. The case of interest is this: Weird but valid platforms where GSI 0-15 are not ISA irqs. Some high numbered GSIs are ISA irqs and use interrupt source overrides to describe them. That is the case on the IBM platform that regressed a bit ago and Iranna D Ankad bisected a failure on. On that IBM platform GSI 0-15 (because the are not ISA irqs) are unusable today. Everything points to this problem I an fixing being the problem with early ES7000 machines, including the memory of their boot firmware developers complaint that they were in spec. Eric