Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261429AbUJ0EER (ORCPT ); Wed, 27 Oct 2004 00:04:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261453AbUJ0EEQ (ORCPT ); Wed, 27 Oct 2004 00:04:16 -0400 Received: from pop5-1.us4.outblaze.com ([205.158.62.125]:41438 "HELO pop5-1.us4.outblaze.com") by vger.kernel.org with SMTP id S261429AbUJ0EEM (ORCPT ); Wed, 27 Oct 2004 00:04:12 -0400 Subject: Re: Fixing MTRR smp breakage and suspending sysdevs. From: Nigel Cunningham Reply-To: ncunningham@linuxmail.org To: Dmitry Torokhov Cc: Linux Kernel Mailing List , "Li, Shaohua" , Pavel Machek , Patrick Mochel In-Reply-To: <200410262250.40674.dtor_core@ameritech.net> References: <16A54BF5D6E14E4D916CE26C9AD30575699E58@pdsmsx402.ccr.corp.intel.com> <200410262220.38052.dtor_core@ameritech.net> <1098847066.5661.47.camel@desktop.cunninghams> <200410262250.40674.dtor_core@ameritech.net> Content-Type: text/plain Message-Id: <1098849333.6269.8.camel@desktop.cunninghams> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6-1mdk Date: Wed, 27 Oct 2004 13:55:33 +1000 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1278 Lines: 34 Hi. On Wed, 2004-10-27 at 13:50, Dmitry Torokhov wrote: > Well, I understand that ACPI is using semaphore and a GFP_KERNEL, but what > is the problem with MTRR? I understand that they should be set with IRQ > off but I highly doibt that enabling IRQ at the end is a requirement. > I think what is described in the commnet is rather a "normal flow of events". The real problem with MTRRs is SMP support: smp_call_function doesn't like IRQs disabled. I got around a similar issue with saving CPU state (for suspend-to-disk) by using the same general sequence that I later discovered described in arch/i386/kernel/cpu/mtrr/main.c (set_mtrr header) for saving CPU contexts. I extended it yesterday to do the MTRR settings as well, before Shaohua pointed to the more general need. Regards, Nigel -- Nigel Cunningham Pastoral Worker Christian Reformed Church of Tuggeranong PO Box 1004, Tuggeranong, ACT 2901 Everyone lives by faith. Some people just don't believe it. Want proof? Try to prove that the theory of evolution is true. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/