From owner-cvs-all@FreeBSD.ORG  Mon Jun 16 17:04:23 2008
Return-Path: <owner-cvs-all@FreeBSD.ORG>
Delivered-To: cvs-all@FreeBSD.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 072C31065671;
	Mon, 16 Jun 2008 17:04:23 +0000 (UTC)
	(envelope-from olli@FreeBSD.org)
Received: from repoman.freebsd.org (repoman.freebsd.org
	[IPv6:2001:4f8:fff6::29])
	by mx1.freebsd.org (Postfix) with ESMTP id E786B8FC19;
	Mon, 16 Jun 2008 17:04:22 +0000 (UTC)
	(envelope-from olli@FreeBSD.org)
Received: from repoman.freebsd.org (localhost [127.0.0.1])
	by repoman.freebsd.org (8.14.1/8.14.1) with ESMTP id m5GH4MjN066707;
	Mon, 16 Jun 2008 17:04:22 GMT
	(envelope-from olli@repoman.freebsd.org)
Received: (from svn2cvs@localhost)
	by repoman.freebsd.org (8.14.1/8.14.1/Submit) id m5GH4Mms066706;
	Mon, 16 Jun 2008 17:04:22 GMT
	(envelope-from olli@repoman.freebsd.org)
Message-Id: <200806161704.m5GH4Mms066706@repoman.freebsd.org>
X-Authentication-Warning: repoman.freebsd.org: svn2cvs set sender to
	olli@repoman.freebsd.org using -f
From: Oliver Fromme <olli@FreeBSD.org>
Date: Mon, 16 Jun 2008 17:04:04 +0000 (UTC)
To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org
X-FreeBSD-CVS-Branch: HEAD
Cc: 
Subject: cvs commit: src/sys/boot/i386/libi386 time.c
X-BeenThere: cvs-all@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: CVS commit messages for the entire tree <cvs-all.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/cvs-all>,
	<mailto:cvs-all-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/cvs-all>
List-Post: <mailto:cvs-all@freebsd.org>
List-Help: <mailto:cvs-all-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/cvs-all>,
	<mailto:cvs-all-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 16 Jun 2008 17:04:23 -0000

olli        2008-06-16 17:04:04 UTC

  FreeBSD src repository

  Modified files:
    sys/boot/i386/libi386 time.c 
  Log:
  SVN rev 179825 on 2008-06-16 17:04:04Z by olli
  
  Implement a workaround for a long-standing problem in
  libi386's time(), caused by a qemu bug.  The bug might
  be present in other BIOSes, too.
  
  qemu either does not simulate the AT RTC correctly or
  has a broken BIOS 1A/02 implementation, and will return
  an incorrect value if the RTC is read while it is being
  updated.
  
  The effect is worsened by the fact that qemu's INT 15/86
  function ("wait" a.k.a. usleep) is non-implmeneted or
  broken and returns immediately, causing beastie.4th to
  spin in a tight loop calling the "read RTC" function
  millions of times, triggering the problem quickly.
  
  Therefore, we keep reading the BIOS value until we get
  the same result twice.  This change fixes beastie.4th's
  countdown under qemu.
  
  Approved by:    des (mentor)
  
  Revision  Changes    Path
  1.6       +32 -8     src/sys/boot/i386/libi386/time.c