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From:   Kaaira Gupta <kgupta@es.iitr.ac.in>
Date:   Mon, 22 Jun 2020 02:02:56 +0530
To:     Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
Cc:     Kaaira Gupta <kgupta@es.iitr.ac.in>,
        Helen Koike <helen.koike@collabora.com>,
        Shuah Khan <skhan@linuxfoundation.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        Kieran Bingham <kieran.bingham@ideasonboard.com>,
        hverkuil@xs4all.nl
Subject: Re: [PATCH v3 2/2] media: vimc: Add a control to display info on
 test image
Message-ID: <20200621203256.GA13040@kaaira-HP-Pavilion-Notebook>
References: <20200618190506.11892-1-kgupta@es.iitr.ac.in>
 <20200618190506.11892-3-kgupta@es.iitr.ac.in>
 <d62583ab-7dd3-9a37-c94d-99fae0f29357@collabora.com>
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On Sat, Jun 20, 2020 at 12:05:28PM +0200, Dafna Hirschfeld wrote:
> Hi, thanks for the patch
> 
> On 18.06.20 21:05, Kaaira Gupta wrote:
> > Add a control in VIMC to display information such as the correct oder of
> > colors for a given test pattern, brightness, hue, saturation, contrast
> > and, width and height at sensor over test image; and display that
> > information.
> > 
> > Signed-off-by: Kaaira Gupta <kgupta@es.iitr.ac.in>
> > ---
> >   drivers/media/test-drivers/vimc/Kconfig       |  2 +
> >   drivers/media/test-drivers/vimc/vimc-common.h |  1 +
> >   drivers/media/test-drivers/vimc/vimc-sensor.c | 47 ++++++++++++++++++-
> >   3 files changed, 49 insertions(+), 1 deletion(-)
> > 
> > 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-common.h b/drivers/media/test-drivers/vimc/vimc-common.h
> > index ae163dec2459..afda52253402 100644
> > --- a/drivers/media/test-drivers/vimc/vimc-common.h
> > +++ b/drivers/media/test-drivers/vimc/vimc-common.h
> > @@ -20,6 +20,7 @@
> >   #define VIMC_CID_VIMC_CLASS		(0x00f00000 | 1)
> >   #define VIMC_CID_TEST_PATTERN		(VIMC_CID_VIMC_BASE + 0)
> >   #define VIMC_CID_MEAN_WIN_SIZE		(VIMC_CID_VIMC_BASE + 1)
> > +#define VIMC_CID_SHOW_INFO		(VIMC_CID_VIMC_BASE + 2)
> >   #define VIMC_FRAME_MAX_WIDTH 4096
> >   #define VIMC_FRAME_MAX_HEIGHT 2160
> > diff --git a/drivers/media/test-drivers/vimc/vimc-sensor.c b/drivers/media/test-drivers/vimc/vimc-sensor.c
> > index a2f09ac9a360..f5352b115aac 100644
> > --- a/drivers/media/test-drivers/vimc/vimc-sensor.c
> > +++ b/drivers/media/test-drivers/vimc/vimc-sensor.c
> > @@ -5,6 +5,7 @@
> >    * Copyright (C) 2015-2017 Helen Koike <helen.fornazier@gmail.com>
> >    */
> > +#include <linux/font.h>
> >   #include <linux/v4l2-mediabus.h>
> >   #include <linux/vmalloc.h>
> >   #include <media/v4l2-ctrls.h>
> > @@ -19,6 +20,7 @@ struct vimc_sen_device {
> >   	struct v4l2_subdev sd;
> >   	struct tpg_data tpg;
> >   	u8 *frame;
> > +	bool show_info;
> 
> I see that vivid saves the 'v4l2_ctrl*' of the controls,
> maybe you should also do that instead of saving a boolean,

Hi, I don't understand..isn't boolean the control?

> 
> >   	/* The active format */
> >   	struct v4l2_mbus_framefmt mbus_format;
> >   	struct v4l2_ctrl_handler hdl;
> > @@ -185,10 +187,29 @@ 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 *order;
> > +	char str[100];
> > +	int line = 1;
> 
> Those vars declarations can be inside the 'if (vsen->show_info)'

I declared it outside because I felt all declarations should be
together?

> 
> >   	struct vimc_sen_device *vsen = container_of(ved, struct vimc_sen_device,
> >   						    ved);
> > -
> >   	tpg_fill_plane_buffer(&vsen->tpg, 0, 0, vsen->frame);
> > +	if (vsen->show_info) {
> > +		tpg_calc_text_basep(&vsen->tpg, basep, 0, vsen->frame);
> > +		order = tpg_g_color_order(&vsen->tpg);
> > +		tpg_gen_text(&vsen->tpg, basep, line++ * 16, 16, order);
> > +		snprintf(str, sizeof(str), " brightness %3d, contrast %3d, saturation %3d, hue %d ",
> > +			 vsen->tpg.brightness,
> > +			 vsen->tpg.contrast,
> > +			 vsen->tpg.saturation,
> > +			 vsen->tpg.hue);
> > +		tpg_gen_text(&vsen->tpg, basep, line++ * 16, 16, str);
> > +
> > +		snprintf(str, sizeof(str), " sensor size: %dx%d",
> > +			 vsen->mbus_format.width, vsen->mbus_format.height);
> > +		tpg_gen_text(&vsen->tpg, basep, line++ * 16, 16, str);
> > +	}
> > +
> >   	return vsen->frame;
> >   }
> > @@ -200,6 +221,14 @@ static int vimc_sen_s_stream(struct v4l2_subdev *sd, int enable)
> >   	if (enable) {
> >   		const struct vimc_pix_map *vpix;
> >   		unsigned int frame_size;
> > +		const struct font_desc *font = find_font("VGA8x16");
> > +
> > +		if (font == NULL) {
> Using 'if (!font)' is the way to check null pointer, instead of compering to null. Running checkpatch.pl with '--strict'
> will catch that.

I didn't do that to be consistent with vivid's style of code. Plus I
thought it makes it more clear to read. Should i change this?

> > +			pr_err("vimc: could not find font\n");
> 'dev_err' should be used instead of 'pr_err'.

yes sorry, i didn't now the difference.

> 
> Also, maybe checking the font here is a bit late, since the user already
> wants to stream and expect the info to be shown.
> Maybe it is better to check the font on 'vimc_sen_s_ctrl'.

Like show the control only of font is available?

I think showing the error is enough maybe?

> 
> Thanks,
> Dafna
> 
> > +			vsen->show_info = 0;
> > +		} else {
> > +			tpg_set_font(font->data);
> > +		}
> >   		/* Calculate the frame size */
> >   		vpix = vimc_pix_map_by_code(vsen->mbus_format.code);
> > @@ -269,6 +298,9 @@ static int vimc_sen_s_ctrl(struct v4l2_ctrl *ctrl)
> >   	case V4L2_CID_SATURATION:
> >   		tpg_s_saturation(&vsen->tpg, ctrl->val);
> >   		break;
> > +	case VIMC_CID_SHOW_INFO:
> > +		vsen->show_info = ctrl->val;
> > +		break;
> >   	default:
> >   		return -EINVAL;
> >   	}
> > @@ -307,6 +339,17 @@ static const struct v4l2_ctrl_config vimc_sen_ctrl_test_pattern = {
> >   	.qmenu = tpg_pattern_strings,
> >   };
> > +static const struct v4l2_ctrl_config vimc_sen_ctrl_show_info = {
> > +	.ops = &vimc_sen_ctrl_ops,
> > +	.id = VIMC_CID_SHOW_INFO,
> > +	.name = "Show Information",
> > +	.type = V4L2_CTRL_TYPE_BOOLEAN,
> > +	.min = 0,
> > +	.max = 1,
> > +	.step = 1,
> > +	.def = 1,
> > +};
> > +
> >   static struct vimc_ent_device *vimc_sen_add(struct vimc_device *vimc,
> >   					    const char *vcfg_name)
> >   {
> > @@ -323,6 +366,7 @@ static struct vimc_ent_device *vimc_sen_add(struct vimc_device *vimc,
> >   	v4l2_ctrl_new_custom(&vsen->hdl, &vimc_sen_ctrl_class, NULL);
> >   	v4l2_ctrl_new_custom(&vsen->hdl, &vimc_sen_ctrl_test_pattern, NULL);
> > +	v4l2_ctrl_new_custom(&vsen->hdl, &vimc_sen_ctrl_show_info, NULL);
> >   	v4l2_ctrl_new_std(&vsen->hdl, &vimc_sen_ctrl_ops,
> >   			  V4L2_CID_VFLIP, 0, 1, 1, 0);
> >   	v4l2_ctrl_new_std(&vsen->hdl, &vimc_sen_ctrl_ops,
> > @@ -362,6 +406,7 @@ static struct vimc_ent_device *vimc_sen_add(struct vimc_device *vimc,
> >   	/* Initialize the frame format */
> >   	vsen->mbus_format = fmt_default;
> > +	vsen->show_info = vimc_sen_ctrl_show_info.def;
> >   	return &vsen->ved;
> >