From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753262Ab3FDXT3 (ORCPT ); Tue, 4 Jun 2013 19:19:29 -0400 Received: from 1wt.eu ([62.212.114.60]:35320 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751136Ab3FDWlu (ORCPT ); Tue, 4 Jun 2013 18:41:50 -0400 Message-Id: <20130604172132.959690964@1wt.eu> User-Agent: quilt/0.48-1 Date: Tue, 04 Jun 2013 19:22:34 +0200 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jiri Slaby , Alan Cox , Greg Kroah-Hartman , Ram Gupta , Willy Tarreau Subject: [ 064/184] serial: 8250, increase PASS_LIMIT In-Reply-To: <58df134a4b98edf5b0073e2e1e988fe6@local> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.32-longterm review patch. If anyone has any objections, please let me know. ------------------ From: Jiri Slaby With virtual machines like qemu, it's pretty common to see "too much work for irq4" messages nowadays. This happens when a bunch of output is printed on the emulated serial console. This is caused by too low PASS_LIMIT. When ISR loops more than the limit, it spits the message. I've been using a kernel with doubled the limit and I couldn't see no problems. Maybe it's time to get rid of the message now? [2.6.32: background info from Ram Gupta] > I need a patch for serial driver that increases PASS_LIMIT merged in > 3.1. I am using 2.6.32 kernel which experiences kernel panic > occasionally. It will be great if you can backport to 2.6.32 and 3.0 > kernel. The commit ID is e7328ae1 serial: 8250, increase PASS_LIMIT Signed-off-by: Jiri Slaby Cc: Alan Cox Signed-off-by: Greg Kroah-Hartman (cherry picked from commit e7328ae1848966181a7ac47e8ae6cddbd2cf55f3) Cc: Ram Gupta Signed-off-by: Willy Tarreau --- drivers/serial/8250.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index 6a451e8..12e1e9e 100644 --- a/drivers/serial/8250.c +++ b/drivers/serial/8250.c @@ -81,7 +81,7 @@ static unsigned int skip_txen_test; /* force skip of txen test at init time */ #define DEBUG_INTR(fmt...) do { } while (0) #endif -#define PASS_LIMIT 256 +#define PASS_LIMIT 512 #define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE) -- 1.7.12.2.21.g234cd45.dirty