From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Egger Subject: Re: [PATCH] xen: more robust serial port driver Date: Tue, 28 Jul 2009 17:03:11 +0200 Message-ID: <200907281703.12002.Christoph.Egger@amd.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Keir Fraser Cc: "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org On Tuesday 28 July 2009 16:58:41 Keir Fraser wrote: > On 28/07/2009 15:47, "Christoph Egger" wrote: > >> Might this be the case for the udelay(100) as > >> well? > > > > No. This ensures, that the write takes effect before the read happens. > > Can a read really overtake a write in this case? Seriously? In real world this can happen on embedded devices, Xen doesn't support. In simulators, things may differ from real hw. > >> And what kinds of systems have these broken UARTs that half-advertise > >> a broken/non-existent FIFO? > > > > The original ns16550 has a broken FIFO. The ns16450 has no FIFO. > > There are simulators which simulate those old things instead of a > > ns16550a. > > Hm, well, okay, the actual one line core of this patch actually seems okay > to me. It's all the rest I want to drop on the floor. Oh, I just noticed that there's a missing '__init' in the function definition of check_existence. Please add it. Tnx. Christoph -- ---to satisfy European Law for business letters: Advanced Micro Devices GmbH Karl-Hammerschmidt-Str. 34, 85609 Dornach b. Muenchen Geschaeftsfuehrer: Thomas M. McCoy, Giuliano Meroni Sitz: Dornach, Gemeinde Aschheim, Landkreis Muenchen Registergericht Muenchen, HRB Nr. 43632