From mboxrd@z Thu Jan 1 00:00:00 1970 From: Trifle Menot Subject: Re: serial performance Date: Sat, 13 Mar 2010 13:53:12 +0000 Message-ID: <201003131353.o2DDrFOF029406@beewyz.com> References: <201003121557.o2CFvlHK023131@beewyz.com> <201003130512.o2D5CnDN027662@beewyz.com> <4B9B4114.2000802@sat.dundee.ac.uk> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4B9B4114.2000802@sat.dundee.ac.uk> Sender: linux-msdos-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: linux-msdos@vger.kernel.org On Sat, 13 Mar 2010 07:39:00 +0000, Paul Crawford wrote: >Trifle Menot wrote: >> With that setting, PCBoard now sees a 16550 when using /dev/ttyS0, and >> my remote output looks fast, like 57600 should. So poking the necessary >> bits into the dosemu virtual UART fixed things up. >Can you elaborate on which bits you poked to achieve this? >We have also had some performance issues with the virtual UART and >anything that makes it more like real-time would be appreciated. I'm not sure, but probably UART FCR0=1. I got the idea from reading PCBoard's help text for the "Force 16550A Usage" setting: > Some multi-tasking environments, such as OS/2 or Windows, use device > drivers to virtualize the comm port. In the process of doing so, they > may hide the 16550A UART, making it appear to be a 16450 UART when > accessed by a DOS application. > Setting the answer to 'Y' tells PCBoard to operate AS IF it had > detected a 16550A chip. >From a quick read of the dosemu source, it seems that the virutal UART defaults to 16450 mode, until you put it into 16550 mode, presumably by poking FCR0=1 into the (virtual) UART. If the app cannot do that on its own, maybe a small C program that does it, prior to launching the app, would achieve the same result. -- Web mail, POP3, and SMTP http://www.beewyz.com/freeaccounts.php