From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755657Ab0IHBo3 (ORCPT ); Tue, 7 Sep 2010 21:44:29 -0400 Received: from mail-ew0-f46.google.com ([209.85.215.46]:51350 "EHLO mail-ew0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750957Ab0IHBo2 convert rfc822-to-8bit (ORCPT ); Tue, 7 Sep 2010 21:44:28 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=dn/l7x+ZTKhePWBViQD6FkGHI36NIuqK4ADX9m75scaCBtMtN2nzw/Ji0zU3LyP0ds aOSjgKbpMaIPk+PDBPfDjykHA35mdyDsYKe9YqUl+3KQ0x3FDDFRrWvHq4ivSIbXbrOJ JlWtyOUWiFfJuU+A1VDo+BUfdiyM4iRPhagkA= MIME-Version: 1.0 In-Reply-To: <1283873872-8633-2-git-send-email-broonie@opensource.wolfsonmicro.com> References: <1283873872-8633-1-git-send-email-broonie@opensource.wolfsonmicro.com> <1283873872-8633-2-git-send-email-broonie@opensource.wolfsonmicro.com> Date: Wed, 8 Sep 2010 10:44:26 +0900 Message-ID: Subject: Re: [PATCH 2/2] spi/spi_s3c64xx: Increase dead reckoning time in wait_for_xfer() From: Jassi Brar To: Mark Brown Cc: Grant Likely , David Brownell , Jassi Brar , spi-devel-general@lists.sourceforge.net, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 8, 2010 at 12:37 AM, Mark Brown wrote: > For small transfers at high speeds the expected transfer time can easily > be well under 1ms, causing the delay in wait_for_xfer() to be only the > dead reckoning fudge factor of 5ms currently included. Experiments on > some of my systems shows that this is marginal for some transfers so > double it to 10ms. > > Signed-off-by: Mark Brown > --- >  drivers/spi/spi_s3c64xx.c |    2 +- >  1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/drivers/spi/spi_s3c64xx.c b/drivers/spi/spi_s3c64xx.c > index 03b28e4..4abb441 100644 > --- a/drivers/spi/spi_s3c64xx.c > +++ b/drivers/spi/spi_s3c64xx.c > @@ -326,7 +326,7 @@ static int wait_for_xfer(struct s3c64xx_spi_driver_data *sdd, > >        /* millisecs to xfer 'len' bytes @ 'cur_speed' */ >        ms = xfer->len * 8 * 1000 / sdd->cur_speed; > -       ms += 5; /* some tolerance */ > +       ms += 10; /* some tolerance */ > >        if (dma_mode) { >                val = msecs_to_jiffies(ms) + 10; Acked-by: Jassi Brar