From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexandre Courbot Subject: Re: Disabling the FIFO on the UART - Bug in 8250 mode? Date: Mon, 14 Jun 2004 15:43:49 +0200 Sender: linux-serial-owner@vger.kernel.org Message-ID: <40CDAB95.1020706@lifl.fr> References: <40CDA6BD.2020606@lifl.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from reserv6.univ-lille1.fr ([193.49.225.20]:64453 "EHLO reserv6.univ-lille1.fr") by vger.kernel.org with ESMTP id S263019AbUFNNpo (ORCPT ); Mon, 14 Jun 2004 09:45:44 -0400 Received: from malonne.lifl.fr (malonne.lifl.fr [134.206.10.29]) by reserv6.univ-lille1.fr (8.12.11/jtpda-5.3.1) with ESMTP id i5EDje0q024458 for ; Mon, 14 Jun 2004 15:45:40 +0200 Received: from lifl.fr (helios.lifl.fr [134.206.10.253]) by malonne.lifl.fr with ESMTP id i5EDjhV03795 for ; Mon, 14 Jun 2004 15:45:43 +0200 (MEST) In-Reply-To: <40CDA6BD.2020606@lifl.fr> List-Id: linux-serial@vger.kernel.org Cc: linux-serial@vger.kernel.org > So I tried doing so (setserial /dev/ttyS0 uart 8250), and that's where > the weird things start. My device then only receives one byte on 16 > (i.e. the latest to enter the FIFO when the serial interrupt is > triggered!). It is clearly stated that a 8250 uart does not have any > FIFO, so I'm starting to suspect a bug here. I've tested on two Linux > x86 machines, runnning kernels 2.6.3 and 2.6.6, the behavior is the > same. I've also tried with UARTs16550 and 16450. Sorry for replying to myself - just to point out that with kernel 2.4.25, on the same machines, it behaves properly (i.e. I'm receiving all the bytes). So it looks like there is a bug in the 2.6 series of the serial driver, not disabling the FIFO when setting the 8250 mode. Would still be nice if it was possible to explicitely disable or tune the 16550A's FIFO with, say, setserial! :) Alex. -- Alexandre Courbot - PhD student RD2P/LIFL http://www.lifl.fr/~courbot