From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752878AbcCKNTa (ORCPT ); Fri, 11 Mar 2016 08:19:30 -0500 Received: from casper.infradead.org ([85.118.1.10]:60817 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752239AbcCKNTX (ORCPT ); Fri, 11 Mar 2016 08:19:23 -0500 Date: Fri, 11 Mar 2016 14:19:17 +0100 From: Peter Zijlstra To: One Thousand Gnomes Cc: Juergen Gross , linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, konrad.wilk@oracle.com, boris.ostrovsky@oracle.com, david.vrabel@citrix.com, mingo@redhat.com, Douglas_Warzecha@dell.com, pali.rohar@gmail.com, jdelvare@suse.com, linux@roeck-us.net, tglx@linutronix.de, hpa@zytor.com, x86@kernel.org Subject: Re: [PATCH 0/6] Support calling functions on dedicated physical cpu Message-ID: <20160311131917.GD6344@twins.programming.kicks-ass.net> References: <1457697574-6710-1-git-send-email-jgross@suse.com> <20160311122514.GA6344@twins.programming.kicks-ass.net> <20160311131504.109cb244@lxorguk.ukuu.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160311131504.109cb244@lxorguk.ukuu.org.uk> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 11, 2016 at 01:15:04PM +0000, One Thousand Gnomes wrote: > On Fri, 11 Mar 2016 13:25:14 +0100 > Peter Zijlstra wrote: > > > On Fri, Mar 11, 2016 at 12:59:28PM +0100, Juergen Gross wrote: > > > Some hardware (e.g. Dell Studio laptops) require special functions to > > > be called on physical cpu 0 in order to avoid occasional hangs. When > > > running as dom0 under Xen this could be achieved only via special boot > > > parameters (vcpu pinning) limiting the hypervisor in it's scheduling > > > decisions. > > > > So instead of telling Dell to get their act together and fix their damn > > firmware, we're going to add the most horrid gunk to the kernel? How > > does that make sense? > > It's been normal forever. The convention with a lot of older BIOS crap > was always that it should be called on the boot CPU (APM. PnPBIOS etc). > > It's a stretch pre-EFI to even call it a "bug" Yeah, I knew about the APM/PnP muck, but I was under the impression this was about new hardware.