Re: [PATCH v3 6/8] media: v4l2-ctrls: Add ARGB color effects control

[Dillon Min <dillon.minfei@gmail.com>]

On Mon, 11 Oct 2021 at 18:04, Hans Verkuil <hverkuil-cisco@xs4all.nl> wrote:
>
> On 11/10/2021 12:00, Dillon Min wrote:
> > Hi Hans
> >
> > Thanks for the quick reply.
> >
> > On Mon, 11 Oct 2021 at 17:40, Hans Verkuil <hverkuil-cisco@xs4all.nl> wrote:
> >>
> >> On 08/10/2021 12:30, dillon.minfei@gmail.com wrote:
> >>> From: Dillon Min <dillon.minfei@gmail.com>
> >>>
> >>> - add V4L2_COLORFX_SET_ARGB color effects control.
> >>> - add V4L2_CID_COLORFX_ARGB for ARGB color setting.
> >>>
> >>> Signed-off-by: Dillon Min <dillon.minfei@gmail.com>
> >>> ---
> >>> v3: according to Hans's suggestion, thanks.
> >>> - remove old stm32 private R2M ioctl
> >>> - add V4L2_CID_COLORFX_ARGB
> >>> - add V4L2_COLORFX_SET_ARGB
> >>>
> >>>  Documentation/userspace-api/media/v4l/control.rst | 8 ++++++++
> >>>  drivers/media/v4l2-core/v4l2-ctrls-defs.c         | 2 ++
> >>>  include/uapi/linux/v4l2-controls.h                | 4 +++-
> >>>  3 files changed, 13 insertions(+), 1 deletion(-)
> >>>
> >>> diff --git a/Documentation/userspace-api/media/v4l/control.rst b/Documentation/userspace-api/media/v4l/control.rst
> >>> index f8d0b923da20..319606a6288f 100644
> >>> --- a/Documentation/userspace-api/media/v4l/control.rst
> >>> +++ b/Documentation/userspace-api/media/v4l/control.rst
> >>> @@ -242,8 +242,16 @@ Control IDs
> >>>      * - ``V4L2_COLORFX_SET_CBCR``
> >>>        - The Cb and Cr chroma components are replaced by fixed coefficients
> >>>       determined by ``V4L2_CID_COLORFX_CBCR`` control.
> >>> +    * - ``V4L2_COLORFX_SET_ARGB``
> >>> +      - ARGB colors.
> >>
> >> How about:
> >>
> >>         - The ARGB components are replaced by the fixed ARGB components
> >>         determined by ``V4L2_CID_COLORFX_ARGB`` control.
> >
> > Sure, will be addressed by v4.
> >
> >>
> >> I also wonder if it makes sense to include the alpha channel here.
> >>
> >> Looking at the driver code it appears to me (I might be wrong) that the alpha
> >> channel is never touched (DMA2D_ALPHA_MODE_NO_MODIF), and setting the alpha
> >> channel as part of a color effects control is rather odd as well.
> >
> > Indeed, Alpha channel is not used in current code. I'll remove this item in v4.
> > how about change the code like below:
> >
> >     * - ``V4L2_COLORFX_SET_RGB``
> >        - The RGB components are replaced by the fixed RGB components
> >          determined by ``V4L2_CID_COLORFX_RGB`` control.
> >
> > ``V4L2_CID_COLORFX_RGB`` ``(integer)``
> >     Determines the Red, Green, and Blue coefficients for
> >     ``V4L2_COLORFX_SET_RGB`` color effect.
> >     Bits [7:0] of the supplied 32 bit value are interpreted as Blue component,
> >     bits [15:8] as Green component, bits [23:16] as Red component, and
> >     bits [31:24] must be zero.
>
> Yes, that looks OK to me.

Ok, after getting your review feedback about the dma2d driver code.
I will submit the v4 version. thanks.

Best Regards.
Dillon

>
> Regards,
>
>         Hans
>
> >
> >
> >>
> >> Alpha channel manipulation really is separate from the color and - if needed - should
> >> be done with a separate control.
> >
> > OK, Will use a separate control when adding blend features.
> >
> > Best Regards,
> > Dillon
> >
> >>
> >> Regards,
> >>
> >>         Hans
> >>
> >>>
> >>>
> >>> +``V4L2_CID_COLORFX_ARGB`` ``(integer)``
> >>> +    Determines the Alpha, Red, Green, and Blue coefficients for
> >>> +    ``V4L2_COLORFX_SET_ARGB`` color effect.
> >>> +    Bits [7:0] of the supplied 32 bit value are interpreted as Blue component,
> >>> +    bits [15:8] as Green component, bits [23:16] as Red component, and
> >>> +    bits [31:24] as Alpha component.
> >>>
> >>>  ``V4L2_CID_COLORFX_CBCR`` ``(integer)``
> >>>      Determines the Cb and Cr coefficients for ``V4L2_COLORFX_SET_CBCR``
> >>> diff --git a/drivers/media/v4l2-core/v4l2-ctrls-defs.c b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> >>> index 421300e13a41..53be6aadb289 100644
> >>> --- a/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> >>> +++ b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> >>> @@ -785,6 +785,7 @@ const char *v4l2_ctrl_get_name(u32 id)
> >>>       case V4L2_CID_MIN_BUFFERS_FOR_OUTPUT:   return "Min Number of Output Buffers";
> >>>       case V4L2_CID_ALPHA_COMPONENT:          return "Alpha Component";
> >>>       case V4L2_CID_COLORFX_CBCR:             return "Color Effects, CbCr";
> >>> +     case V4L2_CID_COLORFX_ARGB:             return "Color Effects, ARGB";
> >>>
> >>>       /*
> >>>        * Codec controls
> >>> @@ -1392,6 +1393,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
> >>>               *min = *max = *step = *def = 0;
> >>>               break;
> >>>       case V4L2_CID_BG_COLOR:
> >>> +     case V4L2_CID_COLORFX_ARGB:
> >>>               *type = V4L2_CTRL_TYPE_INTEGER;
> >>>               *step = 1;
> >>>               *min = 0;
> >>> diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
> >>> index 5532b5f68493..2876c2282a68 100644
> >>> --- a/include/uapi/linux/v4l2-controls.h
> >>> +++ b/include/uapi/linux/v4l2-controls.h
> >>> @@ -128,6 +128,7 @@ enum v4l2_colorfx {
> >>>       V4L2_COLORFX_SOLARIZATION               = 13,
> >>>       V4L2_COLORFX_ANTIQUE                    = 14,
> >>>       V4L2_COLORFX_SET_CBCR                   = 15,
> >>> +     V4L2_COLORFX_SET_ARGB                   = 16,
> >>>  };
> >>>  #define V4L2_CID_AUTOBRIGHTNESS                      (V4L2_CID_BASE+32)
> >>>  #define V4L2_CID_BAND_STOP_FILTER            (V4L2_CID_BASE+33)
> >>> @@ -145,9 +146,10 @@ enum v4l2_colorfx {
> >>>
> >>>  #define V4L2_CID_ALPHA_COMPONENT             (V4L2_CID_BASE+41)
> >>>  #define V4L2_CID_COLORFX_CBCR                        (V4L2_CID_BASE+42)
> >>> +#define V4L2_CID_COLORFX_ARGB                        (V4L2_CID_BASE+43)
> >>>
> >>>  /* last CID + 1 */
> >>> -#define V4L2_CID_LASTP1                         (V4L2_CID_BASE+43)
> >>> +#define V4L2_CID_LASTP1                         (V4L2_CID_BASE+44)
> >>>
> >>>  /* USER-class private control IDs */
> >>>
> >>>
> >>
>