From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: [NAK] Re: [PATCH -v2 9/9] ACPI, APEI, Generic Hardware Error Source POLL/IRQ/NMI notification type support Date: Tue, 26 Oct 2010 12:03:29 +0200 Message-ID: <20101026100329.GB16552@elte.hu> References: <1287992610-14996-1-git-send-email-ying.huang@intel.com> <1287992610-14996-10-git-send-email-ying.huang@intel.com> <20101025084553.GA27119@elte.hu> <20101026072210.GE13036@elte.hu> <1288078222.2862.484.camel@yhuang-dev> <20101026075559.GA9798@elte.hu> <1288081966.2862.571.camel@yhuang-dev> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mx2.mail.elte.hu ([157.181.151.9]:52124 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756404Ab0JZKDz (ORCPT ); Tue, 26 Oct 2010 06:03:55 -0400 Content-Disposition: inline In-Reply-To: <1288081966.2862.571.camel@yhuang-dev> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Huang Ying Cc: Thomas Gleixner , Len Brown , LKML , Andi Kleen , "linux-acpi@vger.kernel.org" , Borislav Petkov , "H. Peter Anvin" , Don Zickus , Linus Torvalds , Andrew Morton , Mauro Carvalho Chehab , "Luck, Tony" * Huang Ying wrote: > On Tue, 2010-10-26 at 15:55 +0800, Ingo Molnar wrote: > > * Huang Ying wrote: > > > > > On Tue, 2010-10-26 at 15:22 +0800, Ingo Molnar wrote: > > > > * Thomas Gleixner wrote: > > > > > > > > > >From Kconfig: > > > > > > > > > > EDAC is designed to report errors in the core system. > > > > > These are low-level errors that are reported in the CPU or > > > > > supporting chipset or other subsystems: > > > > > memory errors, cache errors, PCI errors, thermal throttling, etc.. > > > > > If unsure, select 'Y'. > > > > > > > > > > So please explain why your error reporting is so different from the above that it > > > > > justifies a separate facility. And you better come up with a real good explanation > > > > > other than we looked at EDAC and it did not fit our needs. > > > > > > > > Btw., it's not just about EDAC - the firmware can store Linux events > > > > persistently (beyond allowing the firmware to insert its own RAS events), that > > > > is obviously _hugely_ useful for kernel debugging in general. We could inject > > > > debugging events there and recover them after a crash, etc. > > > > > > Yes. It can be used by other kernel subsystems other than RAS. A kernel API is > > > provided already. The design of the kernel API makes it easy to be used by various > > > kernel subsystems. As the first step, we plan to support saving kernel log before > > > panic and reading it back after reboot. > > > > And that's the problem: we have good facilities already that deal with similar > > things. We have NMI-safe event logging, event enumeration, dump-on-panic code > > and all sorts of goodies there. > > We have provided an in-kernel API for ERST now. And we plan to implement a > kmsg_dumper with ERST. And maybe implement some output support (maybe via some > /dev/kmsg extension) for kmsg_dumper if necessary. So my argument/objection was: " You are introducing a bad ABI here, amongst other problems. Please work with the people who are maintaining sane RAS/event/error reporting ABIs and facilities. You should have done that to begin with. " and your answer to that is: " Hey, we plan to introduce another ad-hoc ABI as well! " ... do you really not see the glaring disconnect? Ingo