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 09:55:59 +0200 Message-ID: <20101026075559.GA9798@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> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mx2.mail.elte.hu ([157.181.151.9]:34314 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753844Ab0JZH40 (ORCPT ); Tue, 26 Oct 2010 03:56:26 -0400 Content-Disposition: inline In-Reply-To: <1288078222.2862.484.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 15:22 +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. But what did Andi's guidance/design lead you to do instead? You stuck a useful hw feature into a vendor specific area of the kernel and exported it to /dev/erst-dbg via a crappy ABI. You also did it in the worst possible imaginable way: you avoided talking to the people who maintain and know the RAS/EDAC/debugging/instrumentation code, and you tried to create an ABI to export it in the most raw form possible - limiting our future options. All that done so that dealing with those pesky RAS/EDAC, instrumentation and core kernel people can be avoided? ;-) Sucks IMHO. Thanks, Ingo