From mboxrd@z Thu Jan 1 00:00:00 1970 From: Erik Rull Subject: Serial Port Driver does not handle interrupt Date: Mon, 09 Nov 2009 16:54:47 +0100 Message-ID: <4AF83B47.9030405@rdsoftware.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit To: "kvm@vger.kernel.org" Return-path: Received: from moutng.kundenserver.de ([212.227.126.186]:51715 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756292AbZKIPyb (ORCPT ); Mon, 9 Nov 2009 10:54:31 -0500 Sender: kvm-owner@vger.kernel.org List-ID: Hi all, I've tested two kvm versions 77 and 88, both with the same behaviour: I add a serial device with -serial /dev/ttyS0 to my guest and launched HyperTerm on my Windows Guest. Additionally I plugged in a loopback plug on the serial connector that just routes back the data send back to the receive line (TXD -> RXD). When I enter characters on the Hyperterm all characters are displayed except the last one that was sent. When I plug in a real serial device and request its status via Hyperterm I get only back the first 16 chars (I expect 50) when I send an additional dummy character (sizeof: 16550 FIFO buffer). On my normal Windows PC it works as expected - so it seems to be an issue with kvm. In the linux host, I don't see any changes in /proc/interrupts, the driver is opened and exclusively on this interrupt line. Within the host the serial line works without any problems, and there, the interrupt counts increase during normal operation with a software that runs on the host and that uses this serial line. What must I do to bring the serial line to real life with a complete communication without any data lost caused by missing interrupts? At the moment this is a key issue that has to be solved to continue my work with kvm. Any Ideas? I also tested other IRQ lines and other ttyS* on the system - same behaviour. Thanks in advance, Erik