Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262812AbTHZX1i (ORCPT ); Tue, 26 Aug 2003 19:27:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262962AbTHZX1i (ORCPT ); Tue, 26 Aug 2003 19:27:38 -0400 Received: from e5.ny.us.ibm.com ([32.97.182.105]:36756 "EHLO e5.ny.us.ibm.com") by vger.kernel.org with ESMTP id S262812AbTHZX1g (ORCPT ); Tue, 26 Aug 2003 19:27:36 -0400 Subject: Re: [PATCH][2.6][2/5]Support for HPET based timer From: john stultz To: Andrew Morton Cc: venkatesh.pallipadi@intel.com, vojtech@suse.cz, Andi Kleen , Dave H , mikpe@csd.uu.se, jun.nakajima@intel.com, suresh.b.siddha@intel.com, lkml In-Reply-To: <20030826115553.7f8b3285.akpm@osdl.org> References: <20030826115129.509c4161.akpm@osdl.org> <20030826115553.7f8b3285.akpm@osdl.org> Content-Type: text/plain Organization: Message-Id: <1061940045.21556.123.camel@cog.beaverton.ibm.com> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.2.4 Date: 26 Aug 2003 16:20:46 -0700 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1136 Lines: 33 On Tue, 2003-08-26 at 11:55, Andrew Morton wrote: > So I suggest you look at the latter option: > > - change time_init() so that it doesn't actually touch the HPET hardware > in the HPET timer case. Well, the difficult part is deciding in time_init() if we are going to use HPET without touching the hardware (to say, check if its actually there). > - add late_time_init() after mem_init(). > > - then do calibrate_delay(). > > Or whatever. The bottom line is that init/main.c is fragile, but not > inviolable ;) We could pick a simple time source (ie: PIT) that would get us through early boot, then choose the real time source in late_time_init(). That would also make implementing the ACPI PM time-source much simpler as we could wait until after ACPI is up, letting us avoid having to parse the tables by hand. However I'm not sure it would be trivial and bug free. ;) -john - 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/