Re: [PATCH v2 1/3] media: imx: imx7-media-csi: Get rid of superfluous call to imx7_csi_mbus_fmt_to_pix_fmt

[Alexander Stein <alexander.stein@ew.tq-group.com>]

Hi Laurent,

thanks or your feedback.

Am Dienstag, 18. April 2023, 11:27:13 CEST schrieb Laurent Pinchart:
> Hi Alexander,
> 
> Thank you for the patch.
> 
> On Tue, Apr 18, 2023 at 09:14:37AM +0200, Alexander Stein wrote:
> > There is no need to convert input pixformat to mbus_framefmt and back
> > again. Instead apply pixformat width contrains directly.
> > 
> > Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
> > ---
> > 
> >  drivers/media/platform/nxp/imx7-media-csi.c | 14 +++++++++-----
> >  1 file changed, 9 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/media/platform/nxp/imx7-media-csi.c
> > b/drivers/media/platform/nxp/imx7-media-csi.c index
> > b701e823436a8..bd649fd9166fd 100644
> > --- a/drivers/media/platform/nxp/imx7-media-csi.c
> > +++ b/drivers/media/platform/nxp/imx7-media-csi.c
> > @@ -1145,8 +1145,8 @@ static const struct imx7_csi_pixfmt *
> > 
> >  __imx7_csi_video_try_fmt(struct v4l2_pix_format *pixfmt,
> >  
> >  			 struct v4l2_rect *compose)
> >  
> >  {
> > 
> > -	struct v4l2_mbus_framefmt fmt_src;
> > 
> >  	const struct imx7_csi_pixfmt *cc;
> > 
> > +	u32 stride;
> > 
> >  	/*
> >  	
> >  	 * Find the pixel format, default to the first supported format if 
not
> > 
> > @@ -1172,12 +1172,16 @@ __imx7_csi_video_try_fmt(struct v4l2_pix_format
> > *pixfmt,> 
> >  		}
> >  	
> >  	}
> > 
> > -	v4l2_fill_mbus_format(&fmt_src, pixfmt, 0);
> > -	imx7_csi_mbus_fmt_to_pix_fmt(pixfmt, &fmt_src, cc);
> 
> Could you please keep the comment from imx7_csi_mbus_fmt_to_pix_fmt()
> here, to indicate where the alignment comes from ?

Sure, why not.

> 	/* Round up width for minimum burst size */
> 
> We should likely revisit this in the future, I don't think the alignment
> is actually needed. This could be recorded already:
> 
> 	/*
> 	 * Round up width for minimum burst size.
> 	 *
> 	 * TODO: Implement configurable stride support, and check what the 
real
> 	 * hardware alignment constraint on the width is.
> 	 */

Sounds good. I was already suspecting actual stride support is not supported, 
as FBUF_PARA is set to 0 (in non-interlaced mode).

> > +	v4l_bound_align_image(&pixfmt->width, 1, 0xffff, 8,
> > +			      &pixfmt->height, 1, 0xffff, 1, 0);
> > +
> > +	stride = round_up((pixfmt->width * cc->bpp) / 8, 8);
> 
> You can drop the round_up(), as pixfmt->width is now a multiple of 8, so
> 
> 	pixfmt->bytesperline = pixfmt->width * cc->bpp / 8;

But that is only identical if cc->bpp == 8, or am I missing something here?

> > +	pixfmt->bytesperline = stride;
> > +	pixfmt->sizeimage = stride * pixfmt->height;
> > 
> >  	if (compose) {
> > 
> > -		compose->width = fmt_src.width;
> > -		compose->height = fmt_src.height;
> > +		compose->width = pixfmt->width;
> 
> This is a change of behaviour, compose->width used to be set to the
> unaligned width.

Oh, you are right. I'll fix that.

Best regards,
Alexander

> > +		compose->height = pixfmt->height;
> > 
> >  	}
> >  	
> >  	return cc;


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