From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261222AbVFJUos (ORCPT ); Fri, 10 Jun 2005 16:44:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261225AbVFJUos (ORCPT ); Fri, 10 Jun 2005 16:44:48 -0400 Received: from mustang.oldcity.dca.net ([216.158.38.3]:55697 "HELO mustang.oldcity.dca.net") by vger.kernel.org with SMTP id S261222AbVFJUoq (ORCPT ); Fri, 10 Jun 2005 16:44:46 -0400 Subject: Re: Attempted summary of "RT patch acceptance" thread From: Lee Revell To: Andrea Arcangeli Cc: "Paul E. McKenney" , Tim Bird , linux-kernel@vger.kernel.org, bhuey@lnxw.com, tglx@linutronix.de, karim@opersys.com, mingo@elte.hu, pmarques@grupopie.com, bruce@andrew.cmu.edu, nickpiggin@yahoo.com.au, ak@muc.de, sdietrich@mvista.com, dwalker@mvista.com, hch@infradead.org, akpm@osdl.org In-Reply-To: <20050610173728.GA6564@g5.random> References: <20050608022646.GA3158@us.ibm.com> <42A8D1F3.8070408@am.sony.com> <20050609235026.GE1297@us.ibm.com> <1118372388.32270.6.camel@mindpipe> <20050610154745.GA1300@us.ibm.com> <20050610173728.GA6564@g5.random> Content-Type: text/plain Date: Fri, 10 Jun 2005 16:45:38 -0400 Message-Id: <1118436338.6423.48.camel@mindpipe> Mime-Version: 1.0 X-Mailer: Evolution 2.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2005-06-10 at 19:37 +0200, Andrea Arcangeli wrote: > You don't need to add it to the document, but as a further pratical > example of troublesome hardware besides VGA (could be a software issue > and not hardware issue though) The VGA problems were due to (X, not kernel!) driver bugs. Recent versions of X are thought to be OK. It's the exact same issue described in this paper, scroll down to section 4.5. http://www.cs.utah.edu/~regehr/papers/hotos7/hotos7.html There's absolutely nothing the kernel or PREEMPT_RT can do about this, AFAICT even RTAI would be affected, because X lets userspace drivers talk directly to the hardware including wedging the PCI bus. Lee