Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934460AbZLKX3m (ORCPT ); Fri, 11 Dec 2009 18:29:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933916AbZLKX3b (ORCPT ); Fri, 11 Dec 2009 18:29:31 -0500 Received: from kroah.org ([198.145.64.141]:50441 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933974AbZLKX3H (ORCPT ); Fri, 11 Dec 2009 18:29:07 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Ian Jackson , Alan Cox , stable , Greg Kroah-Hartman Subject: [PATCH 23/58] Serial: Do not read IIR in serial8250_start_tx when UART_BUG_TXEN Date: Fri, 11 Dec 2009 15:28:07 -0800 Message-Id: <1260574122-10676-23-git-send-email-gregkh@suse.de> X-Mailer: git-send-email 1.6.5.3 In-Reply-To: <20091211232805.GA10652@kroah.com> References: <20091211232805.GA10652@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1626 Lines: 48 From: Ian Jackson Do not read IIR in serial8250_start_tx when UART_BUG_TXEN Reading the IIR clears some oustanding interrupts so it is not safe. Instead, simply transmit immediately if the buffer is empty without regard to IIR. Signed-off-by: Ian Jackson Reviewed-by: Markus Armbruster Reviewed-by: Jiri Kosina Cc: Alan Cox Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/serial/8250.c | 8 +++----- 1 files changed, 3 insertions(+), 5 deletions(-) diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index b75e63e..c3e37c8 100644 --- a/drivers/serial/8250.c +++ b/drivers/serial/8250.c @@ -1339,14 +1339,12 @@ static void serial8250_start_tx(struct uart_port *port) serial_out(up, UART_IER, up->ier); if (up->bugs & UART_BUG_TXEN) { - unsigned char lsr, iir; + unsigned char lsr; lsr = serial_in(up, UART_LSR); up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS; - iir = serial_in(up, UART_IIR) & 0x0f; if ((up->port.type == PORT_RM9000) ? - (lsr & UART_LSR_THRE && - (iir == UART_IIR_NO_INT || iir == UART_IIR_THRI)) : - (lsr & UART_LSR_TEMT && iir & UART_IIR_NO_INT)) + (lsr & UART_LSR_THRE) : + (lsr & UART_LSR_TEMT)) transmit_chars(up); } } -- 1.6.5.5 -- 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/