From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C4597C433EF for ; Wed, 16 Feb 2022 16:09:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236013AbiBPQJx convert rfc822-to-8bit (ORCPT ); Wed, 16 Feb 2022 11:09:53 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:45216 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235210AbiBPQJw (ORCPT ); Wed, 16 Feb 2022 11:09:52 -0500 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 09429BBE03 for ; Wed, 16 Feb 2022 08:09:38 -0800 (PST) Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nKMs3-0007Kl-OM; Wed, 16 Feb 2022 17:09:35 +0100 Received: from [2a0a:edc0:0:900:1d::4e] (helo=lupine) by drehscheibe.grey.stw.pengutronix.de with esmtp (Exim 4.94.2) (envelope-from ) id 1nKMs2-00GzCC-S5; Wed, 16 Feb 2022 17:09:34 +0100 Received: from pza by lupine with local (Exim 4.94.2) (envelope-from ) id 1nKMs0-001lH9-A3; Wed, 16 Feb 2022 17:09:32 +0100 Message-ID: <89a08ce1cdb1cf0b4d46b916e7107eca0796ca9d.camel@pengutronix.de> Subject: Re: [PATCH] gpu: ipu-v3: Fix dev_dbg frequency output From: Philipp Zabel To: Mark Jonas , David Airlie , Daniel Vetter Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, tingquan.ruan@cn.bosch.com Date: Wed, 16 Feb 2022 17:09:32 +0100 In-Reply-To: <20220207151411.5009-1-mark.jonas@de.bosch.com> References: <20220207151411.5009-1-mark.jonas@de.bosch.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT User-Agent: Evolution 3.38.3-1 MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: p.zabel@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Mark, On Mon, 2022-02-07 at 16:14 +0100, Mark Jonas wrote: > From: Leo Ruan > > This commit corrects the printing of the IPU clock error percentage if > it is between -0.1% to -0.9%. For example, if the pixel clock requested > is 27.2 MHz but only 27.0 MHz can be achieved the deviation is -0.8%. > But the fixed point math had a flaw and calculated error of 0.2%. > > Before: >   Clocks: IPU 270000000Hz DI 24716667Hz Needed 27200000Hz >   IPU clock can give 27000000 with divider 10, error 0.2% >   Want 27200000Hz IPU 270000000Hz DI 24716667Hz using IPU, 27000000Hz > > After: >   Clocks: IPU 270000000Hz DI 24716667Hz Needed 27200000Hz >   IPU clock can give 27000000 with divider 10, error -0.8% >   Want 27200000Hz IPU 270000000Hz DI 24716667Hz using IPU, 27000000Hz > > Signed-off-by: Leo Ruan > Signed-off-by: Mark Jonas > --- >  drivers/gpu/ipu-v3/ipu-di.c | 5 +++-- >  1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/ipu-v3/ipu-di.c b/drivers/gpu/ipu-v3/ipu-di.c > index b4a31d506fcc..74eca68891ad 100644 > --- a/drivers/gpu/ipu-v3/ipu-di.c > +++ b/drivers/gpu/ipu-v3/ipu-di.c > @@ -451,8 +451,9 @@ static void ipu_di_config_clock(struct ipu_di *di, >   >                 error = rate / (sig->mode.pixelclock / 1000); >   > -               dev_dbg(di->ipu->dev, "  IPU clock can give %lu with divider %u, error %d.%u%%\n", > -                       rate, div, (signed)(error - 1000) / 10, error % 10); > +               dev_dbg(di->ipu->dev, "  IPU clock can give %lu with divider %u, error %c%d.%d%%\n", > +                       rate, div, error < 1000 ? '-' : '+', > +                       abs(error - 1000) / 10, abs(error - 1000) % 10); >   >                 /* Allow a 1% error */ >                 if (error < 1010 && error >= 990) { Rounding (always down) is still a bit unintuitive, but this certainly improves things. Reviewed-by: Philipp Zabel regards Philipp