From mboxrd@z Thu Jan 1 00:00:00 1970 From: Colin Laplace Subject: Possible bug in serial driver 8250/8250-fourport Date: Fri, 3 Mar 2006 17:14:25 +0100 Message-ID: <200603031714.26023.haiku@bloodshed.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from ip-218.36.113.64.sbbsnet.net ([64.113.36.218]:16398 "EHLO john.anime.com.ar") by vger.kernel.org with ESMTP id S932101AbWCCQPQ (ORCPT ); Fri, 3 Mar 2006 11:15:16 -0500 Received: from [192.168.2.5] (133.Red-88-7-215.staticIP.rima-tde.net [88.7.215.133]) by cobalt-eth1.anime.com.ar (8.10.2/8.10.2) with ESMTP id k23G6BE25622 for ; Fri, 3 Mar 2006 11:06:12 -0500 Content-Disposition: inline Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: linux-serial@vger.kernel.org Hello, I am writing to this list because i am now clueless on a problem i am having with writing data on a serial port, and now the only thing i can think of is a serial driver bug. The situation is the following : I have a NetMos Technology PCI 9845 Multi-I/O Controller (rev 01), which has four ports. Each of its ports are connected as follow : - port 1 TX connected to a Midi Chipset DREAM SAM9708 port 1 port 1 RX connected to FATAR midi keyboard - port 2 TX connected to a Midi Chipset DREAM SAM9708 port 2 - port 3 connected to an external midi in/out (1) - port 4 connected to an external midi in/out (2) This configuration has been tested on both kernel 2.6.10 with 8250 module, and 2.6.15 with 8250-fourport module, the problem arises on both. Each of the serial ports are configured this way : setserial /dev/tts/$id uart 16550A port 0x$addr irq $irq ^fourport spd_cust divisor 8 low_latency The problem is as follow : When playing MIDI data over port 1, sometimes the output just stops, the data doesn't go anymore to the Dream 1 port. Then (and that's the strange part), if we press a key of the FATAR keyboard (connected to the same serial port but on RX), all the data that was not played comes out all of a sudden, and the playback continues to be output normally. This problem does *NOT* happen on any of the other serial ports, only on the one where TX is connected to the dream 1 and RX to the FATAR midi keyboard. I have been trying with both snd-serialmidi alsa driver, as well with a homemade user-land program which drives midi events to the serial port, and the problems happens on both ways. Also, very important to note : NO error messages are given by write() calls when the problem arises, nor do i get kernel messages. This situation happens very often. If you need any other information please let me know. I would really appreciate any feedback you could have about this matter. Best regards, Colin Laplace