From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ralf Baechle Subject: Re: [PATCH] serial: fix au1xxx UART0 irq setup Date: Mon, 29 Oct 2007 15:28:25 +0000 Message-ID: <20071029152824.GB3953@linux-mips.org> References: <4720A11E.5060101@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from ftp.linux-mips.org ([194.74.144.162]:52594 "EHLO ftp.linux-mips.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755441AbXJ2P3J (ORCPT ); Mon, 29 Oct 2007 11:29:09 -0400 Received: from localhost.localdomain ([127.0.0.1]:15753 "EHLO dl5rb.ham-radio-op.net") by ftp.linux-mips.org with ESMTP id S20022687AbXJ2P3I (ORCPT ); Mon, 29 Oct 2007 15:29:08 +0000 Content-Disposition: inline In-Reply-To: <4720A11E.5060101@gmail.com> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Jan Nikitenko Cc: linux-mips@linux-mips.org, linux-serial@vger.kernel.org On Thu, Oct 25, 2007 at 03:58:54PM +0200, Jan Nikitenko wrote: > UART0 on Alchemy mips platforms (au1xxx) does not use real uart's hw > irq, causing 'ttyS0: 1 input overrun(s)' kernel message with data loss, > when more characters than uart's fifo size were to be received by the uart. > > This problem can be experienced for example when uart0 is used as a > serial console on au1550 and more than 16 characters are pasted from > clipboard to the console. > > The is_real_interrupt(irq) macro is defined in drivers/serial/8250.c as > a check, if the irq number is other than zero. > Because UART0 on au1xxx platforms uses irq number 0, the > is_real_interrupt() check fails and serial8250_backup_timeout() is used > instead of uart's hw irq. > > The patch redefines the is_real_interrupt(irq) macro, as suggested in > the comment above the macro definition in 8250.c, in the > asm-mips/serial.h to be always true for CONFIG_SERIAL_8250_AU1X00. > This allows the irq number 0 to be used as hw irq for the alchemy uart0 > and fixes the overrun problem. > > Signed-off-by: Jan Nikitenko So applied to all of lmo's -stable branches. Ralf