From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751461AbaC1HRW (ORCPT ); Fri, 28 Mar 2014 03:17:22 -0400 Received: from mail-ee0-f54.google.com ([74.125.83.54]:57345 "EHLO mail-ee0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751072AbaC1HRV (ORCPT ); Fri, 28 Mar 2014 03:17:21 -0400 Date: Fri, 28 Mar 2014 08:17:16 +0100 From: Ingo Molnar To: Feng Tang Cc: tglx@linutronix.de, mingo@elte.hu, hpa@zytor.com, linux-kernel@vger.kernel.org, John Stultz , Clemens Ladisch , Andy Lutomirski Subject: Re: [PATCH v2] x86: hpet: Don't default CONFIG_HPET_TIMER to be y for X86_64 Message-ID: <20140328071716.GC30107@gmail.com> References: <1395975316-4795-1-git-send-email-feng.tang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1395975316-4795-1-git-send-email-feng.tang@intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Feng Tang wrote: > On many new phone/tablet platforms like Baytrail/Merrifield etc, the > HPET are either defeatured or has some problem to be used as a > reliable timer. As these platforms also have X86_64, we should not > make HPET_TIMER default y for all X86_64. NAK! If the HPET is unreliable on a specific platform then any of the following solutions would address the problem (in order of preference): - the hardware should not expose it. Why waste silicon on something that does not work? - or the firmware should not expose it. Why expose something that does not work? - or the kernel should have a quirk to reliably disable it. Why should we crash or misbehave if a driver is built into the kernel? tweaking a default is _NOT_ a solution for an unreliable hpet. Thanks, Ingo