From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759579AbYFJVbn (ORCPT ); Tue, 10 Jun 2008 17:31:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759437AbYFJVbY (ORCPT ); Tue, 10 Jun 2008 17:31:24 -0400 Received: from smtp121.sbc.mail.sp1.yahoo.com ([69.147.64.94]:24915 "HELO smtp121.sbc.mail.sp1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1759423AbYFJVbX (ORCPT ); Tue, 10 Jun 2008 17:31:23 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=pacbell.net; h=Received:X-YMail-OSG:X-Yahoo-Newman-Property:From:To:Subject:Date:User-Agent:Cc:References:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding:Content-Disposition:Message-Id; b=mPIc0a+k37qkgZRnlzE+U5zlyXYQXZjxYK4OH6fNlKX6WMzHvdb+FqM2IF1ht0mmF8dXa5QjwQW0pLQhLGxRkaY76IJrR2f0dNDMUr2KUR1R4R3v8uLnxkxD/qE3ZpCWnLEfeXaBQyxGom73iaueuO/wWty2sAft3CdVBIUIYik= ; X-YMail-OSG: ZLmkXmMVM1l.rasd294SmdkYROMwat.paWrgu9WvBMz8fbn.gyU74H7K59_B.Ej6fNYDYSSGPY6RGgy2XP59wUxnWzZFegauws4B_V12w7.aS4UZQc61UkoOE2Dcf4FIVRg- X-Yahoo-Newman-Property: ymail-3 From: David Brownell To: Maxim Levitsky Subject: Re: [patch 2.6.26-rc5] make HPET_RTC_IRQ track HPET_EMULATE_RTC Date: Tue, 10 Jun 2008 14:31:21 -0700 User-Agent: KMail/1.9.9 Cc: Andrew Morton , lkml , Thomas Gleixner References: <200806052241.44713.david-b@pacbell.net> <200806061644.23449.maximlevitsky@gmail.com> In-Reply-To: <200806061644.23449.maximlevitsky@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200806101431.21402.david-b@pacbell.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday 06 June 2008, Maxim Levitsky wrote: > Remember long ago I had a discussion with you about HPET that > steals RTC irq in 'legacy replacement' mode, and rtc driver thus > implements rtc on 'top' of hpet. > > New rtc-cmos driver doesn't do this emulation, thus it isn't compatible > with hpet driver. That was fixed in 9d8af78b07976d4d84e0df491abd4e9db848d0ad (February) by Bernhard Walle ... if you look at the bug report associated with this patch, you'll see that rtc-cmos was working OK with HPET, it's just the legacy RTC driver which got confused after the recent updates to clock handling. > But there is a solution, I didn't agree with firstly, but then I did, and > I do agree now, and that to put hpet in normal mode. > > What happened with patches that put hpet in normal independent mode? The story from either Ingo or Thomas (I forget who) was that this is another case where we have to cope with BIOS braindamage. Not enough BIOS vendors expose the relevant IRQ routing that Linux could default to using HPET in what I'd call "sane" mode. Now, that still kind of implies there could be an option to use sane HPET IRQ configuration (doesn't hijack RTC and other IRQs, and there could be a per-CPU HPET) on at least the systems where that IRQ routing is available. Over time I'd hope that systems like that could become the common case. But ... someone else would have to do that work. :) - Dave