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 4AF3EC61DA4 for ; Thu, 2 Feb 2023 08:13:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229633AbjBBINw (ORCPT ); Thu, 2 Feb 2023 03:13:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33478 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229632AbjBBINv (ORCPT ); Thu, 2 Feb 2023 03:13:51 -0500 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DA41079C9D for ; Thu, 2 Feb 2023 00:13:49 -0800 (PST) Received: from pendragon.ideasonboard.com (unknown [193.209.96.36]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 50D2B505; Thu, 2 Feb 2023 09:13:48 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1675325628; bh=g8PfGIOpPRSeZrhvN9oZOqenLkYKFsUSp6zGoWjhmVE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=l/pLMZVeZT3soGbn30QwesqR8RWIneNrvL56tCpvqyz6UCpHd2/hqgdUYlmEOcWj1 D4x9JEnc/cKTMoav3yz2RFAMXMfbxX4V1793sT4TkoWkCIkjlMJ2fOccqt2uEM1fHI upin1PjG1fbmuGASS9rZo5+8/c+DyMSrcFiahs2Q= Date: Thu, 2 Feb 2023 10:13:46 +0200 From: Laurent Pinchart To: Dave Stevenson Cc: Manivannan Sadhasivam , Mauro Carvalho Chehab , linux-media@vger.kernel.org Subject: Re: [PATCH 04/11] media: i2c: imx290: Fix the pixel rate at 148.5Mpix/s Message-ID: References: <20230131192016.3476937-1-dave.stevenson@raspberrypi.com> <20230131192016.3476937-5-dave.stevenson@raspberrypi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20230131192016.3476937-5-dave.stevenson@raspberrypi.com> Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi Dave, Thank you for the patch. On Tue, Jan 31, 2023 at 07:20:09PM +0000, Dave Stevenson wrote: > The datasheet lists the link frequency changes between > 1080p and 720p modes. This is correct that the link frequency > changes as measured on an oscilloscope. > > Link frequency is not necessarily the same as pixel rate. That's right. The model where htotal * vtotal * frame rate = pixel rate applies to the pixel array. Things can be retimed when transmitted over CSI-2 (or over anything, really), with pixels transmitted at a higher or lower rate, with smaller or larger blanking, as long as it matches the total horizontal line length in time units. I suppose this could in theory be done vertically too, but that would require too much memory. I hope we'll never have a need, on the receiver side, to know the active line length in time units as sent over CSI-2 :-) > The datasheet gives standard configurations for 1080p and 720p > modes at a number of frame rates. > Looking at the 1080p mode it gives: > HMAX = 0x898 = 2200 > VMAX = 0x465 = 1125 > 2200 * 1125 * 60fps = 148.5MPix/s > > Looking at the 720p mode it gives: > HMAX = 0xce4 = 3300 > VMAX = 0x2ee = 750 > 3300 * 750 * 60fps = 148.5Mpix/s > > This driver currently scales the pixel rate proportionally to the > link frequency, however the above shows that this is not the > correct thing to do, and currently all frame rate and exposure > calculations give incorrect results. > > Correctly report the pixel rate as being 148.5MPix/s under any > mode. > > Signed-off-by: Dave Stevenson > --- > drivers/media/i2c/imx290.c | 15 ++++----------- > 1 file changed, 4 insertions(+), 11 deletions(-) > > diff --git a/drivers/media/i2c/imx290.c b/drivers/media/i2c/imx290.c > index 12946ca9d8d2..bd8729aed43c 100644 > --- a/drivers/media/i2c/imx290.c > +++ b/drivers/media/i2c/imx290.c > @@ -107,6 +107,7 @@ > > #define IMX290_VMAX_DEFAULT 1125 > > +#define IMX290_PIXEL_RATE 148500000 A blank line is missing here. With this fixed, Reviewed-by: Laurent Pinchart > /* > * The IMX290 pixel array is organized as follows: > * > @@ -190,7 +191,6 @@ struct imx290 { > > struct v4l2_ctrl_handler ctrls; > struct v4l2_ctrl *link_freq; > - struct v4l2_ctrl *pixel_rate; > struct v4l2_ctrl *hblank; > struct v4l2_ctrl *vblank; > }; > @@ -649,15 +649,8 @@ static void imx290_ctrl_update(struct imx290 *imx290, > { > unsigned int hblank = mode->hmax - mode->width; > unsigned int vblank = IMX290_VMAX_DEFAULT - mode->height; > - s64 link_freq = imx290_link_freqs_ptr(imx290)[mode->link_freq_index]; > - u64 pixel_rate; > - > - /* pixel rate = link_freq * 2 * nr_of_lanes / bits_per_sample */ > - pixel_rate = link_freq * 2 * imx290->nlanes; > - do_div(pixel_rate, imx290_format_info(format->code)->bpp); > > __v4l2_ctrl_s_ctrl(imx290->link_freq, mode->link_freq_index); > - __v4l2_ctrl_s_ctrl_int64(imx290->pixel_rate, pixel_rate); > > __v4l2_ctrl_modify_range(imx290->hblank, hblank, hblank, 1, hblank); > __v4l2_ctrl_modify_range(imx290->vblank, vblank, vblank, 1, vblank); > @@ -707,9 +700,9 @@ static int imx290_ctrl_init(struct imx290 *imx290) > if (imx290->link_freq) > imx290->link_freq->flags |= V4L2_CTRL_FLAG_READ_ONLY; > > - imx290->pixel_rate = v4l2_ctrl_new_std(&imx290->ctrls, &imx290_ctrl_ops, > - V4L2_CID_PIXEL_RATE, > - 1, INT_MAX, 1, 1); > + v4l2_ctrl_new_std(&imx290->ctrls, &imx290_ctrl_ops, V4L2_CID_PIXEL_RATE, > + IMX290_PIXEL_RATE, IMX290_PIXEL_RATE, 1, > + IMX290_PIXEL_RATE); > > v4l2_ctrl_new_std_menu_items(&imx290->ctrls, &imx290_ctrl_ops, > V4L2_CID_TEST_PATTERN, -- Regards, Laurent Pinchart