Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030279AbWHRRE7 (ORCPT ); Fri, 18 Aug 2006 13:04:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030291AbWHRRE7 (ORCPT ); Fri, 18 Aug 2006 13:04:59 -0400 Received: from caramon.arm.linux.org.uk ([217.147.92.249]:7944 "EHLO caramon.arm.linux.org.uk") by vger.kernel.org with ESMTP id S1030279AbWHRRE6 (ORCPT ); Fri, 18 Aug 2006 13:04:58 -0400 Date: Fri, 18 Aug 2006 18:04:51 +0100 From: Russell King To: Lee Revell Cc: Giampaolo Tomassoni , Linux Kernel ML , Alan Cox , Paul Fulghum Subject: Re: R: How to avoid serial port buffer overruns? Message-ID: <20060818170450.GC21101@flint.arm.linux.org.uk> Mail-Followup-To: Lee Revell , Giampaolo Tomassoni , Linux Kernel ML , Alan Cox , Paul Fulghum References: <1155920400.24907.63.camel@mindpipe> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1155920400.24907.63.camel@mindpipe> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2026 Lines: 47 On Fri, Aug 18, 2006 at 01:00:00PM -0400, Lee Revell wrote: > On Fri, 2006-08-18 at 10:48 +0200, Giampaolo Tomassoni wrote: > > > On Thu, 2006-08-17 at 00:19 +0100, Russell King wrote: > > > > > > > > > OK, thanks. FWIW here is the serial board we are using: > > > > > > http://www.moschip.com/html/MCS9845.html > > > > > > The hardware guy says "The mn9845cv, have in default 2 serial ports and > > > one ISA bus, where we have connected the tl16c554, quad serial port." > > > > > > Hopefully Ingo's latency tracer can tell me what is holding off > > > interrupts. > > > > I beg your pardon: I'm not used that much to interrupts handling in Linux, but this piece of code from sound/drivers/serial-u16550.c in a linux-2.6.16: > > OK, they are not using serial-u16550 but 8250_fourport for some reason: Doesn't look like it. fourport cards have their ports at 0x1a0..0x1bf and 0x2a0..0x2bf, and have some special and non-standard features. > # cat /proc/tty/driver/serial > serinfo:1.0 driver revision: > 0: uart:16550A port:000003F8 irq:4 tx:0 rx:0 > 1: uart:unknown port:000002B8 irq:5 > 2: uart:unknown port:000003E8 irq:4 > 3: uart:unknown port:000002E8 irq:3 > 4: uart:16550A port:0000DD00 irq:185 tx:234335 rx:47502 RTS|DTR > 5: uart:16550A port:0000E300 irq:185 tx:249926 rx:27732 RTS|DTR > 6: uart:16550A port:0000E400 irq:185 tx:120958 rx:0 RTS|DTR > 7: uart:16550A port:0000D000 irq:185 tx:0 rx:0 > 8: uart:16550A port:0000D100 irq:185 tx:0 rx:0 RTS|DTR > 9: uart:16550A port:0000D200 irq:185 tx:0 rx:123406 RTS|DTR > > It looks like no overruns are reported, but I have to find out whether > they have reproduced the bug since the last reboot. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 Serial core - 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/