From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mathias Nyman Subject: Re: serial8250: too much work for irq73 Date: Thu, 03 Feb 2011 17:05:32 +0200 Message-ID: <4D4AC43C.4060206@nokia.com> References: <4D483062.9010809@mibtec.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from smtp.nokia.com ([147.243.128.24]:19724 "EHLO mgw-da01.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755282Ab1BCOxh (ORCPT ); Thu, 3 Feb 2011 09:53:37 -0500 In-Reply-To: <4D483062.9010809@mibtec.de> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: =?ISO-8859-15?Q?ext_Robert_W=F6rle?= Cc: linux-omap@vger.kernel.org ext Robert W=F6rle wrote: > Hi List >=20 > I am running into issues , when using ttyS1 on a heavy loaded > application. It trys to send and recieve around 60bytes every 100ms w= ith > 57600baud. There is a PIC Microcontroller attached on the otherside > which immidiatly returns the data when requested. >=20 > After some hours , the kernel starts to flood with the above messages > and the system gets into an unusable state. >=20 > i am running 2.6.35.9 ( released from isee.com ) on their Igep Module= ( > arch igep0030). >=20 > What would you guys do ? Anything i can provide you to help here ? It= s > really a major issue for us and showstopping an important release. >=20 > Thanks in advance for any help or suggestion >=20 Not sure if this is the same cause, but here's some code that fixed a s= imilar issue: Serial: 8250.c: Clear FIFOs before enabling them There's a short time when FIFO's are disabled and interrupts enabled between startup and set_termios. If rx FIFO is not cleared before enabled, and there are lots of serial = I/O, an interrupt indicating FIFO data error can occur. (LSR register bit 7 set, no other error bits set). The current interrupt handle is unable to clear this interrupt and will= continue looping with a flood of "too much work" messages. This is seen on an omap board with ST16654 type uart if a key is kept p= ressed in serial console while booting. Signed-off-by: Mathias Nyman --- drivers/serial/8250.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index 5ed1b82..d3add25 100644 --- a/drivers/serial/8250.c +++ b/drivers/serial/8250.c @@ -2403,6 +2403,8 @@ serial8250_set_termios(struct uart_port *port, st= ruct ktermios *termios, if (fcr & UART_FCR_ENABLE_FIFO) { /* emulated UARTs (Lucent Venus 167x) need two = steps */ serial_outp(up, UART_FCR, UART_FCR_ENABLE_FIFO)= ; + serial_outp(up, UART_FCR, UART_FCR_ENABLE_FIFO = | + UART_FCR_CLEAR_RCVR | UART_FCR_CLEA= R_XMIT); } serial_outp(up, UART_FCR, fcr); /* set fcr */ } --=20 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html