Re: [PATCH 4/9] media: vsp1: Add support for missing 32-bit RGB formats

From: Jacopo Mondi <jacopo@jmondi.org>
To: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Cc: dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org,
	linux-renesas-soc@vger.kernel.org,
	Maxime Ripard <maxime.ripard@bootlin.com>
Subject: Re: [PATCH 4/9] media: vsp1: Add support for missing 32-bit RGB formats
Date: Thu, 4 Apr 2019 19:39:05 +0200	[thread overview]
Message-ID: <20190404173905.n6mupqzvcr5vwhwu@uno.localdomain> (raw)
In-Reply-To: <20190328070723.26553-5-laurent.pinchart+renesas@ideasonboard.com>

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HI Laurent,
  if you help me out understanding the bit swapping procedure in VSP
I would be more confident in saying I actually reviewed the series.

On Thu, Mar 28, 2019 at 09:07:18AM +0200, Laurent Pinchart wrote:
> Add support for the V4L2_PIX_FMT_BGRA32, V4L2_PIX_FMT_BGRX32,
> V4L2_PIX_FMT_RGBA32 and V4L2_PIX_FMT_RGBX32 formats to the VSP driver.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> ---
>  drivers/media/platform/vsp1/vsp1_pipe.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
>
> diff --git a/drivers/media/platform/vsp1/vsp1_pipe.c b/drivers/media/platform/vsp1/vsp1_pipe.c
> index 54ff539ffea0..9f08d85e89d7 100644
> --- a/drivers/media/platform/vsp1/vsp1_pipe.c
> +++ b/drivers/media/platform/vsp1/vsp1_pipe.c
> @@ -68,6 +68,20 @@ static const struct vsp1_format_info vsp1_video_formats[] = {
>  	{ V4L2_PIX_FMT_XBGR32, MEDIA_BUS_FMT_ARGB8888_1X32,
>  	  VI6_FMT_ARGB_8888, VI6_RPF_DSWAP_P_LLS | VI6_RPF_DSWAP_P_LWS,
>  	  1, { 32, 0, 0 }, false, false, 1, 1, false },
> +	{ V4L2_PIX_FMT_BGRA32, MEDIA_BUS_FMT_ARGB8888_1X32,
> +	  VI6_FMT_RGBA_8888, VI6_RPF_DSWAP_P_LLS | VI6_RPF_DSWAP_P_LWS,
> +	  1, { 32, 0, 0 }, false, false, 1, 1, true },
> +	{ V4L2_PIX_FMT_BGRX32, MEDIA_BUS_FMT_ARGB8888_1X32,
> +	  VI6_FMT_RGBA_8888, VI6_RPF_DSWAP_P_LLS | VI6_RPF_DSWAP_P_LWS,
> +	  1, { 32, 0, 0 }, false, false, 1, 1, false },
> +	{ V4L2_PIX_FMT_RGBA32, MEDIA_BUS_FMT_ARGB8888_1X32,
> +	  VI6_FMT_RGBA_8888, VI6_RPF_DSWAP_P_LLS | VI6_RPF_DSWAP_P_LWS |
> +	  VI6_RPF_DSWAP_P_WDS | VI6_RPF_DSWAP_P_BTS,
> +	  1, { 32, 0, 0 }, false, false, 1, 1, true },
> +	{ V4L2_PIX_FMT_RGBX32, MEDIA_BUS_FMT_ARGB8888_1X32,
> +	  VI6_FMT_RGBA_8888, VI6_RPF_DSWAP_P_LLS | VI6_RPF_DSWAP_P_LWS |
> +	  VI6_RPF_DSWAP_P_WDS | VI6_RPF_DSWAP_P_BTS,
> +	  1, { 32, 0, 0 }, false, false, 1, 1, false },

So, this is how I interpret the above lines for format BGRA32 (the
same applies to RGBA32 fwiw)

        Bytes:          B3      B2      B1      B0
Input: ARGB8888_1X32:   A       R       G       B
Out:   BGRA32           R       G       B       A

If I apply LLS and LWS on the "Input Row", according to the table I get

 Position in Table 32.10:    0  1  2  3
 IN Components ordering:     A  R  G  B  (ARGB8888_1X32
 Position in Table 32.10:    3  2  1  0  (with LLS and LWS applied)
 OUT Components ordering:    B  G  R  A

Which to me is the ordering of components of the format named
V4L2_PIX_FMT_ARGB32 and not BGRA32 which is instead, as reported RGBA
(GREAT naming here!)

What am I doing wrong?

Thanks
  j

>  	{ V4L2_PIX_FMT_ARGB32, MEDIA_BUS_FMT_ARGB8888_1X32,
>  	  VI6_FMT_ARGB_8888, VI6_RPF_DSWAP_P_LLS | VI6_RPF_DSWAP_P_LWS |
>  	  VI6_RPF_DSWAP_P_WDS | VI6_RPF_DSWAP_P_BTS,
> --
> Regards,
>
> Laurent Pinchart
>

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