From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758665Ab0JVSWX (ORCPT ); Fri, 22 Oct 2010 14:22:23 -0400 Received: from kroah.org ([198.145.64.141]:41941 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755789Ab0JVSWV (ORCPT ); Fri, 22 Oct 2010 14:22:21 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: David Daney , Greg Kroah-Hartman Subject: [PATCH 32/49] serial: 8250: Don't delay after transmitter is ready. Date: Fri, 22 Oct 2010 11:21:11 -0700 Message-Id: <1287771688-14805-32-git-send-email-gregkh@suse.de> X-Mailer: git-send-email 1.7.1 In-Reply-To: <20101022175112.GC13489@kroah.com> References: <20101022175112.GC13489@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: David Daney The loop in wait_for_xmitr() is delaying one extra uS after the ready condition has been met. Rewrite the loop to only delay if the transmitter is not ready. Signed-off-by: David Daney Signed-off-by: Greg Kroah-Hartman --- drivers/serial/8250.c | 6 ++++-- 1 files changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index 24110f6..31b8cca 100644 --- a/drivers/serial/8250.c +++ b/drivers/serial/8250.c @@ -1867,15 +1867,17 @@ static void wait_for_xmitr(struct uart_8250_port *up, int bits) unsigned int status, tmout = 10000; /* Wait up to 10ms for the character(s) to be sent. */ - do { + for (;;) { status = serial_in(up, UART_LSR); up->lsr_saved_flags |= status & LSR_SAVE_FLAGS; + if ((status & bits) == bits) + break; if (--tmout == 0) break; udelay(1); - } while ((status & bits) != bits); + } /* Wait up to 1s for flow control if necessary */ if (up->port.flags & UPF_CONS_FLOW) { -- 1.7.2