Re: [PATCH v5 1/5] media: qcom: camss: Add V4L2 meta format for CAMSS ISP parameters

On Thu, Jul 30, 2026 at 1:57=E2=80=AFPM Bryan O'Donoghue <[email protected]> w=
rote:
>
> On 30/07/2026 12:44, Loic Poulain wrote:
> > On Wed, Jul 29, 2026 at 8:28=E2=80=AFPM Gjorgji Rosikopulos (Consultant=
)
> > <[email protected]> wrote:
> >>
> >> Hi Loic,
> >>
> >> On 7/24/2026 3:42 PM, Loic Poulain wrote:
> >>> Add a V4L2 meta format code (V4L2_META_FMT_QCOM_ISP_PARAMS) for the
> >>> Qualcomm CAMSS ISP parameter buffer. This format is used by the param=
s
> >>> video node exposed by CAMSS offline ISP drivers (e.g. OPE) to carry
> >>> ISP tuning data such as white balance, color correction and chroma
> >>> enhancement settings.
> >>>
> >>> Signed-off-by: Loic Poulain <[email protected]>
> >>> ---
> >>>   drivers/media/v4l2-core/v4l2-ioctl.c | 1 +
> >>>   include/uapi/linux/videodev2.h       | 3 +++
> >>>   2 files changed, 4 insertions(+)
> >>>
> >>> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l=
2-core/v4l2-ioctl.c
> >>> index 98512ea4cc5b9d725e1851af2ed38df85bb4fa8c..7b6e9a9a514f037190d55=
d59409dd6cc97522943 100644
> >>> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> >>> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> >>> @@ -1471,6 +1471,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdes=
c *fmt)
> >>>        case V4L2_META_FMT_C3ISP_STATS:         descr =3D "Amlogic C3 =
ISP Statistics"; break;
> >>>        case V4L2_META_FMT_MALI_C55_PARAMS:     descr =3D "ARM Mali-C5=
5 ISP Parameters"; break;
> >>>        case V4L2_META_FMT_MALI_C55_STATS:      descr =3D "ARM Mali-C5=
5 ISP 3A Statistics"; break;
> >>> +     case V4L2_META_FMT_QCOM_ISP_PARAMS:     descr =3D "Qualcomm CAM=
SS ISP Parameters"; break;
> >>>        case V4L2_PIX_FMT_NV12_8L128:   descr =3D "NV12 (8x128 Linear)=
"; break;
> >>>        case V4L2_PIX_FMT_NV12M_8L128:  descr =3D "NV12M (8x128 Linear=
)"; break;
> >>>        case V4L2_PIX_FMT_NV12_10BE_8L128:      descr =3D "10-bit NV12=
 (8x128 Linear, BE)"; break;
> >>> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/vide=
odev2.h
> >>> index add08188f06890182a5c399a223c1ab0a546cae1..011026194a20cde22a374=
e6fb2570cbc6bced230 100644
> >>> --- a/include/uapi/linux/videodev2.h
> >>> +++ b/include/uapi/linux/videodev2.h
> >>> @@ -888,6 +888,9 @@ struct v4l2_pix_format {
> >>>   #define V4L2_META_FMT_MALI_C55_PARAMS        v4l2_fourcc('C', '5', =
'5', 'P') /* ARM Mali-C55 Parameters */
> >>>   #define V4L2_META_FMT_MALI_C55_STATS v4l2_fourcc('C', '5', '5', 'S'=
) /* ARM Mali-C55 3A Statistics */
> >>>
> >>> +/* Vendor specific - used for Qualcomm CAMSS offline ISP */
> >>
> >> It seems that this is generic format for ISP parameters, can we update=
 the comment and remove offline. The proposal:
> >> /* Vendor specific - used for Qualcomm CAMSS ISP */
> >
> > Sure.
> > Loic
>
> Since these are not the full list and as I understand them not the full
> structures for OPE - qcom restricting the full formats ? - I'd request
> to move these to an OPE specific header.

Yes, I think the params struct can be OPE-specific and defined in an
OPE-specific header. However, could we keep the enum in a generic
header so that we only have a single enum definition? We could then
extend it later with OPE-specific or non-OPE-specific parameters as
needed.

Regards,
Loic