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Date: Fri, 2 Nov 2012 18:09:18 +0400
From: Kirill Smelkov <kirr@mns.spb.ru>
To: Hans Verkuil <hverkuil@xs4all.nl>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>,
	linux-media@vger.kernel.org
Subject: Re: [PATCH v3] [media] vivi: Teach it to tune FPS
Message-ID: <20121102140918.GA6849@tugrik.mns.mnsspb.ru>
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On Tue, Oct 23, 2012 at 05:35:21PM +0400, Kirill Smelkov wrote:
> On Tue, Oct 23, 2012 at 08:40:04AM +0200, Hans Verkuil wrote:
> > On Mon October 22 2012 19:01:40 Kirill Smelkov wrote:
> > > On Mon, Oct 22, 2012 at 04:16:14PM +0200, Hans Verkuil wrote:
> > > > On Mon October 22 2012 15:54:44 Kirill Smelkov wrote:
> > > > > I was testing my video-over-ethernet subsystem today, and vivi seemed to
> > > > > be perfect video source for testing when one don't have lots of capture
> > > > > boards and cameras. Only its framerate was hardcoded to NTSC's 30fps,
> > > > > while in my country we usually use PAL (25 fps). That's why the patch.
> > > > > Thanks.
> > > > 
> > > > Rather than introducing a module option, it's much nicer if you can
> > > > implement enum_frameintervals and g/s_parm. This can be made quite flexible
> > > > allowing you to also support 50/59.94/60 fps.
> > > 
> > > Thanks for feedback. I've reworked the patch for FPS to be set via
> > > ->{g,s}_parm(), and yes now it is more flexble, because one can set
> > > different FPS on different vivi devices. Only I don't know V4L2 ioctls
> > > details well enough and various drivers do things differently. The patch
> > > is below. Is it ok?
> > 
> > Close, but it's not quite there.
> > 
> > You should run the v4l2-compliance tool from the v4l-utils.git repository
> > (take the master branch). That will report any errors in your implementation.
> > 
> > In this case g/s_parm doesn't set readbuffers (set it to 1) and if timeperframe
> > equals { 0, 0 }, then you should get a nominal framerate (let's stick to 29.97
> > for that). I would set the nominal framerate whenever the denominator == 0.
> > 
> > For vidioc_enum_frameintervals you need to check the IN fields and fill in the
> > stepwise struct.
> 
> Thanks for pointers and info about v4l2-compliance handy-tool. I've
> tried to correct all the issues you mentioned above and here is the
> patch.
> 
> (Only requirement to set stepwise.step to 1.0 for
>  V4L2_FRMIVAL_TYPE_CONTINUOUS seems a bit illogical to me, but anyway,
>  that's what the V4L2 spec requires...)
> 
> Thanks,
> Kirill
> 
> ---- 8< ----
> From: Kirill Smelkov <kirr@mns.spb.ru>
> Date: Tue, 23 Oct 2012 16:56:59 +0400
> Subject: [PATCH v3] [media] vivi: Teach it to tune FPS
> 
> I was testing my video-over-ethernet subsystem yesterday, and vivi
> seemed to be perfect video source for testing when one don't have lots
> of capture boards and cameras. Only its framerate was hardcoded to
> NTSC's 30fps, while in my country we usually use PAL (25 fps) and I
> needed that to precisely simulate bandwidth.
> 
> That's why here is this patch with ->enum_frameintervals() and
> ->{g,s}_parm() implemented as suggested by Hans Verkuil which passes
> v4l2-compliance and manual testing through v4l2-ctl -P / -p <fps>.
> 
> Regarding newly introduced __get_format(u32 pixelformat) I decided not
> to convert original get_format() to operate on fourcc codes, since >= 3
> places in driver need to deal with v4l2_format and otherwise it won't be
> handy.
> 
> Thanks.
> 
> Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru>
> ---
>  drivers/media/platform/vivi.c | 84 ++++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 75 insertions(+), 9 deletions(-)
> 
> V3:
>     - corrected issues with V4L2 spec compliance as pointed by Hans
>       Verkuil.
> 
> V2:
> 
>     - reworked FPS setting from module param to via ->{g,s}_parm() as suggested
>       by Hans Verkuil.
> 
> 
> diff --git a/drivers/media/platform/vivi.c b/drivers/media/platform/vivi.c
> index 3e6902a..3adea58 100644
> --- a/drivers/media/platform/vivi.c
> +++ b/drivers/media/platform/vivi.c
> @@ -36,10 +36,6 @@
>  
>  #define VIVI_MODULE_NAME "vivi"
>  
> -/* Wake up at about 30 fps */
> -#define WAKE_NUMERATOR 30
> -#define WAKE_DENOMINATOR 1001
> -
>  #define MAX_WIDTH 1920
>  #define MAX_HEIGHT 1200
>  
> @@ -69,6 +65,9 @@ MODULE_PARM_DESC(vid_limit, "capture memory limit in megabytes");
>  /* Global font descriptor */
>  static const u8 *font8x16;
>  
> +/* default to NTSC timeperframe */
> +static const struct v4l2_fract TPF_DEFAULT = {.numerator = 1001, .denominator = 30000};
> +
>  #define dprintk(dev, level, fmt, arg...) \
>  	v4l2_dbg(level, debug, &dev->v4l2_dev, fmt, ## arg)
>  
> @@ -150,14 +149,14 @@ static struct vivi_fmt formats[] = {
>  	},
>  };
>  
> -static struct vivi_fmt *get_format(struct v4l2_format *f)
> +static struct vivi_fmt *__get_format(u32 pixelformat)
>  {
>  	struct vivi_fmt *fmt;
>  	unsigned int k;
>  
>  	for (k = 0; k < ARRAY_SIZE(formats); k++) {
>  		fmt = &formats[k];
> -		if (fmt->fourcc == f->fmt.pix.pixelformat)
> +		if (fmt->fourcc == pixelformat)
>  			break;
>  	}
>  
> @@ -167,6 +166,11 @@ static struct vivi_fmt *get_format(struct v4l2_format *f)
>  	return &formats[k];
>  }
>  
> +static struct vivi_fmt *get_format(struct v4l2_format *f)
> +{
> +	return __get_format(f->fmt.pix.pixelformat);
> +}
> +
>  /* buffer for one video frame */
>  struct vivi_buffer {
>  	/* common v4l buffer stuff -- must be first */
> @@ -232,6 +236,7 @@ struct vivi_dev {
>  
>  	/* video capture */
>  	struct vivi_fmt            *fmt;
> +	struct v4l2_fract          timeperframe;
>  	unsigned int               width, height;
>  	struct vb2_queue	   vb_vidq;
>  	unsigned int		   field_count;
> @@ -660,8 +665,8 @@ static void vivi_thread_tick(struct vivi_dev *dev)
>  	dprintk(dev, 2, "[%p/%d] done\n", buf, buf->vb.v4l2_buf.index);
>  }
>  
> -#define frames_to_ms(frames)					\
> -	((frames * WAKE_NUMERATOR * 1000) / WAKE_DENOMINATOR)
> +#define frames_to_ms(dev, frames)				\
> +	((frames * dev->timeperframe.numerator * 1000) / dev->timeperframe.denominator)
>  
>  static void vivi_sleep(struct vivi_dev *dev)
>  {
> @@ -677,7 +682,7 @@ static void vivi_sleep(struct vivi_dev *dev)
>  		goto stop_task;
>  
>  	/* Calculate time to wake up */
> -	timeout = msecs_to_jiffies(frames_to_ms(1));
> +	timeout = msecs_to_jiffies(frames_to_ms(dev, 1));
>  
>  	vivi_thread_tick(dev);
>  
> @@ -1049,6 +1054,63 @@ static int vidioc_s_input(struct file *file, void *priv, unsigned int i)
>  	return 0;
>  }
>  
> +/* timeperframe is arbitrary and continous */
> +static int vidioc_enum_frameintervals(struct file *file, void *priv,
> +					     struct v4l2_frmivalenum *fival)
> +{
> +	struct vivi_fmt *fmt;
> +
> +	if (fival->index)
> +		return -EINVAL;
> +
> +	fmt = __get_format(fival->pixel_format);
> +	if (!fmt)
> +		return -EINVAL;
> +
> +	/* regarding width width & height - we support any */
> +
> +	fival->type = V4L2_FRMIVAL_TYPE_CONTINUOUS;
> +
> +	/* fill in stepwise as required by V4L2 spec, i.e.
> +	 *
> +	 * min <= (step = 1.0) <= max
> +	 */
> +	fival->stepwise.step = (struct v4l2_fract) {1, 1};
> +	fival->stepwise.min  = (struct v4l2_fract) {1, 1};
> +	fival->stepwise.max  = (struct v4l2_fract) {2, 1};
> +
> +	return 0;
> +}
> +
> +static int vidioc_g_parm(struct file *file, void *priv, struct v4l2_streamparm *parm)
> +{
> +	struct vivi_dev *dev = video_drvdata(file);
> +
> +	if (parm->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
> +		return -EINVAL;
> +
> +	parm->parm.capture.capability   = V4L2_CAP_TIMEPERFRAME;
> +	parm->parm.capture.timeperframe = dev->timeperframe;
> +	parm->parm.capture.readbuffers  = 1;
> +	return 0;
> +}
> +
> +static int vidioc_s_parm(struct file *file, void *priv, struct v4l2_streamparm *parm)
> +{
> +	struct vivi_dev *dev = video_drvdata(file);
> +
> +	if (parm->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
> +		return -EINVAL;
> +
> +	dev->timeperframe = parm->parm.capture.timeperframe.denominator ?
> +		parm->parm.capture.timeperframe :
> +		TPF_DEFAULT;	/* {*, 0} resets timing */
> +
> +	parm->parm.capture.timeperframe = dev->timeperframe;
> +	parm->parm.capture.readbuffers  = 1;
> +	return 0;
> +}
> +
>  /* --- controls ---------------------------------------------- */
>  
>  static int vivi_g_volatile_ctrl(struct v4l2_ctrl *ctrl)
> @@ -1207,6 +1269,9 @@ static const struct v4l2_ioctl_ops vivi_ioctl_ops = {
>  	.vidioc_enum_input    = vidioc_enum_input,
>  	.vidioc_g_input       = vidioc_g_input,
>  	.vidioc_s_input       = vidioc_s_input,
> +	.vidioc_enum_frameintervals = vidioc_enum_frameintervals,
> +	.vidioc_g_parm        = vidioc_g_parm,
> +	.vidioc_s_parm        = vidioc_s_parm,
>  	.vidioc_streamon      = vb2_ioctl_streamon,
>  	.vidioc_streamoff     = vb2_ioctl_streamoff,
>  	.vidioc_log_status    = v4l2_ctrl_log_status,
> @@ -1265,6 +1330,7 @@ static int __init vivi_create_instance(int inst)
>  		goto free_dev;
>  
>  	dev->fmt = &formats[0];
> +	dev->timeperframe = TPF_DEFAULT;
>  	dev->width = 640;
>  	dev->height = 480;
>  	dev->pixelsize = dev->fmt->depth / 8;
> -- 
> 1.8.0.rc3.331.g5b9a629

Ping. Is maybe something wrong with it?