Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759500AbYFQVzp (ORCPT ); Tue, 17 Jun 2008 17:55:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757488AbYFQVzi (ORCPT ); Tue, 17 Jun 2008 17:55:38 -0400 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:39736 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755652AbYFQVzh (ORCPT ); Tue, 17 Jun 2008 17:55:37 -0400 Date: Tue, 17 Jun 2008 22:38:09 +0100 From: Alan Cox To: "Nameer Yarkon" Cc: linux-kernel@vger.kernel.org Subject: Re: Serial problem and request for guidance.. Message-ID: <20080617223809.56d65635@lxorguk.ukuu.org.uk> In-Reply-To: References: <20080616130353.1b80fdd0@lxorguk.ukuu.org.uk> X-Mailer: Claws Mail 3.4.0 (GTK+ 2.12.8; x86_64-redhat-linux-gnu) Organization: Red Hat UK Cyf., Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, Y Deyrnas Gyfunol. Cofrestrwyd yng Nghymru a Lloegr o'r rhif cofrestru 3798903 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 999 Lines: 22 > on ARM (OMAP) with an old 2.6.14 kernel, but only when I enable the > debug macros of the line discipline code (hci_h4, hci_ldisc,..). > When a big chunk of data arrives, more than > half of it is lost. even on 115200. But when I turn of the debug macros (BT_DBG Not a suprise. The old buffering would struggle in this case. > macros which are simply a bunch of prinks) the problem disappears. So I suspect > there are some nasty timing issues which lead to data loss. > > I encountered similar problems last year even on a PC, with pre 2.6.21 kernels > (around 2.6.19 or even earlier IIRC) but it was all gone with 2.6.21 and 2.6.22. We rewrote the tty buffering around the point it magically started working so that would fit my suspicion. Alan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/