Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264246AbUJHTNF (ORCPT ); Fri, 8 Oct 2004 15:13:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263778AbUJHTJq (ORCPT ); Fri, 8 Oct 2004 15:09:46 -0400 Received: from h-68-165-86-241.dllatx37.covad.net ([68.165.86.241]:4700 "EHLO sol.microgate.com") by vger.kernel.org with ESMTP id S270083AbUJHSU7 (ORCPT ); Fri, 8 Oct 2004 14:20:59 -0400 Subject: [PATCH] serial receive lockup fix From: Paul Fulghum To: Marcelo Tosatti Cc: linux-kernel Content-Type: text/plain Message-Id: <1097259655.1475.3.camel@deimos.microgate.com> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 Date: Fri, 08 Oct 2004 13:20:56 -0500 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1274 Lines: 37 Fix lockup caused by serial driver not clearing receive interrupt if flip buffer becomes full. Signed-off-by: Paul Fulghum --- a/drivers/char/serial.c 2004-09-29 09:08:35.000000000 -0500 +++ b/drivers/char/serial.c 2004-09-29 09:09:07.000000000 -0500 @@ -573,8 +573,19 @@ do { if (tty->flip.count >= TTY_FLIPBUF_SIZE) { tty->flip.tqueue.routine((void *) tty); - if (tty->flip.count >= TTY_FLIPBUF_SIZE) + if (tty->flip.count >= TTY_FLIPBUF_SIZE) { + /* no room in flip buffer, discard rx FIFO contents to clear IRQ + * *FIXME* Hardware with auto flow control + * would benefit from leaving the data in the FIFO and + * disabling the rx IRQ until space becomes available. + */ + do { + serial_inp(info, UART_RX); + icount->overrun++; + *status = serial_inp(info, UART_LSR); + } while ((*status & UART_LSR_DR) && (max_count-- > 0)); return; // if TTY_DONT_FLIP is set + } } ch = serial_inp(info, UART_RX); *tty->flip.char_buf_ptr = ch; - 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/