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Date:   Mon, 8 Jun 2020 15:12:38 +0300
From:   Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To:     Hans Verkuil <hverkuil@xs4all.nl>
Cc:     Dafna Hirschfeld <dafna.hirschfeld@collabora.com>,
        Kaaira Gupta <kgupta@es.iitr.ac.in>,
        linux-media@vger.kernel.org,
        Helen Koike <helen.koike@collabora.com>,
        Shuah Khan <skhan@linuxfoundation.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        linux-kernel@vger.kernel.org, kieran.bingham@ideasonboard.com
Subject: Re: [RFC PATCH] vimc: Add colors' order over test image
Message-ID: <20200608121238.GB5896@pendragon.ideasonboard.com>
References: <20200607135325.GA16838@kaaira-HP-Pavilion-Notebook>
 <5866f6c9-36c7-ffe3-41b3-94f184cd9e5d@collabora.com>
 <38db03a4-6b22-c341-103c-ed0d4dcce856@xs4all.nl>
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Hello,

On Mon, Jun 08, 2020 at 11:33:21AM +0200, Hans Verkuil wrote:
> On 08/06/2020 09:10, Dafna Hirschfeld wrote:
> > On 07.06.20 15:53, Kaaira Gupta wrote:
> >> Currently there is no method to know if the test image generated by vimc
> >> is correct (except for comparing it with a known 'correct' image). Add
> >> text over the test image, representing the correct order of colors.
> >>
> >> I have sent it as an RFC because we can add the text as an optional
> >> control, and maybe we can print some other useful information as well
> >> (like vivid does).
> > 
> > Yes, it seems like a good idea to add it as a control of the sensor.
> > 
> >> Signed-off-by: Kaaira Gupta <kgupta@es.iitr.ac.in>
> >> --->   drivers/media/test-drivers/vimc/Kconfig       | 2 ++
> >>   drivers/media/test-drivers/vimc/vimc-core.c   | 9 +++++++++
> >>   drivers/media/test-drivers/vimc/vimc-sensor.c | 8 ++++++++
> >>   3 files changed, 19 insertions(+)
> >>
> >> diff --git a/drivers/media/test-drivers/vimc/Kconfig b/drivers/media/test-drivers/vimc/Kconfig
> >> index 4068a67585f9..da4b2ad6e40c 100644
> >> --- a/drivers/media/test-drivers/vimc/Kconfig
> >> +++ b/drivers/media/test-drivers/vimc/Kconfig
> >> @@ -2,6 +2,8 @@
> >>   config VIDEO_VIMC
> >>   	tristate "Virtual Media Controller Driver (VIMC)"
> >>   	depends on VIDEO_DEV && VIDEO_V4L2
> >> +	select FONT_SUPPORT
> >> +	select FONT_8x16
> >>   	select MEDIA_CONTROLLER
> >>   	select VIDEO_V4L2_SUBDEV_API
> >>   	select VIDEOBUF2_VMALLOC
> >> diff --git a/drivers/media/test-drivers/vimc/vimc-core.c b/drivers/media/test-drivers/vimc/vimc-core.c
> >> index 11210aaa2551..8142bfbcbd49 100644
> >> --- a/drivers/media/test-drivers/vimc/vimc-core.c
> >> +++ b/drivers/media/test-drivers/vimc/vimc-core.c
> >> @@ -5,10 +5,12 @@
> >>    * Copyright (C) 2015-2017 Helen Koike <helen.fornazier@gmail.com>
> >>    */
> >>   
> >> +#include <linux/font.h>
> >>   #include <linux/init.h>
> >>   #include <linux/module.h>
> >>   #include <linux/platform_device.h>
> >>   #include <media/media-device.h>
> >> +#include <media/tpg/v4l2-tpg.h>
> >>   #include <media/v4l2-device.h>
> >>   
> >>   #include "vimc-common.h"
> >> @@ -265,7 +267,14 @@ static int vimc_probe(struct platform_device *pdev)
> >>   {
> >>   	struct vimc_device *vimc;
> >>   	int ret;
> >> +	const struct font_desc *font = find_font("VGA8x16");
> >>   
> >> +	if (font == NULL) {
> >> +		pr_err("vimc: could not find font\n");
> >> +		return -ENODEV;
> >> +	}
> >> +
> >> +	tpg_set_font(font->data);
> > 
> > I think the code that set the format should move to the
> > code that registers the sensor in vimc-sensor.c
> > 
> >>   	dev_dbg(&pdev->dev, "probe");
> >>   
> >>   	vimc = kzalloc(sizeof(*vimc), GFP_KERNEL);
> >> diff --git a/drivers/media/test-drivers/vimc/vimc-sensor.c b/drivers/media/test-drivers/vimc/vimc-sensor.c
> >> index a2f09ac9a360..4b13955c502a 100644
> >> --- a/drivers/media/test-drivers/vimc/vimc-sensor.c
> >> +++ b/drivers/media/test-drivers/vimc/vimc-sensor.c
> >> @@ -185,10 +185,18 @@ static const struct v4l2_subdev_pad_ops vimc_sen_pad_ops = {
> >>   static void *vimc_sen_process_frame(struct vimc_ent_device *ved,
> >>   				    const void *sink_frame)
> >>   {
> >> +	u8 *basep[TPG_MAX_PLANES][2];
> >> +	char str[100];
> >>   	struct vimc_sen_device *vsen = container_of(ved, struct vimc_sen_device,
> >>   						    ved);
> >>   
> >> +	tpg_calc_text_basep(&vsen->tpg, basep, 0, vsen->frame);
> >>   	tpg_fill_plane_buffer(&vsen->tpg, 0, 0, vsen->frame);
> >> +
> >> +	snprintf(str, sizeof(str),
> >> +		 "Order: white, yellow, cyan, green, magenta, red, blue, black");
> > The colors are generated by the tpg, so I think it should be a feature of the tpg to print the colors.
> 
> I agree. The tpg knows where each color is and based on the width and height it can
> print the text. A tpg_gen_pattern_text() function that does the work would be very
> nice.

Could we go one step further, and print the colour name on each colour
bar ?

> It also doesn't make sense for all patterns, so this is really a nice feature to
> incorporate into the TPG itself and enable it via a vivid and vimc control.
> 
> > For example, a function in v4l2-tpg-core.c that get the pattern as an argument and return
> > this string, or maybe returns a const pointer to the array of colors, or something like that.
> > Then maybe we can add a control in vivid for the same tpg feature.
> > 
> > Note also that the sensor has a control to change the pattern: vimc_sen_ctrl_test_pattern
> > So the string depends on that pattern.
> > 
> >> +	tpg_gen_text(&vsen->tpg, basep, 1, 1, str);
> >> +
> >>   	return vsen->frame;
> >>   }
> >>   

-- 
Regards,

Laurent Pinchart