From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753095Ab2C0M7M (ORCPT ); Tue, 27 Mar 2012 08:59:12 -0400 Received: from www.linutronix.de ([62.245.132.108]:33526 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751275Ab2C0M7I (ORCPT ); Tue, 27 Mar 2012 08:59:08 -0400 Date: Tue, 27 Mar 2012 14:58:58 +0200 (CEST) From: Thomas Gleixner To: Jan Beulich cc: mingo@elte.hu, hirofumi@mail.parknet.co.jp, linux-kernel@vger.kernel.org, hpa@zytor.com Subject: Re: hpet_disable() call sites In-Reply-To: <4F719449020000780007B0CD@nat28.tlf.novell.com> Message-ID: References: <4F719449020000780007B0CD@nat28.tlf.novell.com> User-Agent: Alpine 2.02 (LFD 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 27 Mar 2012, Jan Beulich wrote: > up kernel has a problem if the HPET is in an unexpected state, in > particular preventing "normal" timer interrupts from occurring (which > was in particular found to be the case during kdump attempts after > Xen was running). What's Xen doing special with the hpet ? > Is there any reason why hpet_disable() should not also be called > from (or some equivalent action be taken, perhaps including clearing > certain bits in the individual counters' configuration registers, which > are apparently - but perhaps wrongly - implied to be clear in e.g. > hpet_set_mode(), in) hpet_enable()? No, there is no particular reason why we don't clear those registers. Thanks, tglx