Re: [RFC PATCH v6 02/11] media: v4l2: Extend pixel formats to unify single/multi-planar handling (and more)

Laurent Pinchart
2022-11-06T19:25:19Z

Hi Hsia-Jun,

On Sat, Nov 05, 2022 at 11:19:10PM +0800, Hsia-Jun Li wrote:
> Hello Helen
>
> I didn't see any updates from V6 and V7-WIP in your repo. That is what I
> need to for our complex tile formats in our platform.
>
> Any future plane here?
>
> Besides I have some ideas on these patches.
>
> On 2/24/21 23:12, Helen Koike wrote:
> > Hi Hans,
> >
> > Thank you for your comment, please see my reply below.
> >
> > On 2/23/21 9:35 AM, Hans Verkuil wrote:
> >> Hi Helen,
> >>
> >> On 14/01/2021 19:07, Helen Koike wrote:
> >>> This is part of the multiplanar and singleplanar unification process.
> >>> v4l2_ext_pix_format is supposed to work for both cases.
> >>>
> >>> We also add the concept of modifiers already employed in DRM to expose
> >>> HW-specific formats (like tiled or compressed formats) and allow
> >>> exchanging this information with the DRM subsystem in a consistent way.
> >>>
> >>> Note that only V4L2_BUF_TYPE_VIDEO_[OUTPUT,CAPTURE] are accepted in
> >>> v4l2_ext_format, other types will be rejected if you use the
> >>> {G,S,TRY}_EXT_PIX_FMT ioctls.
> >>>
> >>> New hooks have been added to v4l2_ioctl_ops to support those new ioctls
> >>> in drivers, but, in the meantime, the core takes care of converting
> >>> {S,G,TRY}_EXT_PIX_FMT requests into {S,G,TRY}_FMT so that old drivers
> >>> can
> >>> still work if the userspace app/lib uses the new ioctls.
> >>>
> >>> The conversion is also done the other around to allow userspace
> >>> apps/libs using {S,G,TRY}_FMT to work with drivers implementing the
> >>> _ext_ hooks.
> >>
> >> I have some small comments below, but also one high level comment:
> >>
> >> Regarding M variants of pixelformats: this patch 'normalizes' them to
> >> regular pixelformats in the extended API. This makes life complicated,
> >> and I wonder if this is the right approach.
> >>
> >> Currently there are two reasons for a driver to support e.g. NV12M:
> >> either luma and chroma need to be in two memory banks, or the luma
> >> and chroma planes cannot be contiguous due to alignment requirements.
> >>
> >> The first requirement is still valid for drivers that support the
> >> extended API.
> >> The second requirement is no longer a reason to support NV12M. But I
> >> don't think we should just drop NV12M support if it was already supported
> >> before the conversion to this extended API. Since NV12M allocates two
> >> buffers
> >> instead of one, it is still different from a regular NV12.
> >
> > I don't see what would be the difference when using NV12 and NV12M in
> > Ext API.
> > NV12 could be used for both requirements. It would even allow the second
> > requirement with a single memory buffer.
> >
> Although I don't have problem here to support both single and multiple
> planes in our hardware. But using the single plane format here is not
> convience for us.
>
> The tile format in our platform is little complex, you can't calculate
> the stride and sizeimage easily with just the modifier, width and
> height. Then we don't have a good place to record the offset here.

What else is needed to compute those values ? Can they be computed by
the kernel driver, or do they have computed by userspace ?

> Besides, the luma and chroma planes would always need their own
> compression meta data planes. If we use NV12 here, that would make a
> very strange pixel format, one plane for the pixel datas and two planes
> for the meta data.
>
> >> I would prefer that such drivers support both NV12 and NV12M, so no
> >> automatic conversion.
> >>
> >> A related question is how to handle pixelformat enumeration: with the
> >> extended API an NV12 format might work, but not with the old API (e.g.
> >> due to memory alignment requirements). I wonder if a
> >> VIDIOC_ENUM_EXT_PIX_FMT
> >> isn't needed.
> >
> > We need VIDIOC_ENUM_EXT_PIX_FMT for modifiers, but we can add it later.
> > If the driver reports NV12M, userspace can use it and the framework
> > normilizes it.
> >
> >>
> >> VIDIOC_ENUM_EXT_PIX_FMT would report NV12 and NV12M, while
> >> VIDIOC_ENUM_FMT
> >> would just report NV12M.
> >
> > If NV12 and NV12M are equivalent in Ext API, I don't see why we would
> > report both (unless I'm missing something, which is probably the case).
> >
> > The idea was to deprecate the M-variants one day.
>
> I was thinking the way in DRM API is better, always assuming it would
> always in a multiple planes. The only problem is we don't have a way to
> let the allocator that allocate contiguous memory for planes when we
> need to do that.
>
> >>> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> >>> Signed-off-by: Helen Koike <helen.koike@collabora.com>
> >>> ---
> >>>
> >>> Changes in v6:
> >>>   The main change here was fixing the conversion, so planes reflects
> >>> color planes,
> >>>   and to implement this properly I made major refactors compared to
> >>> the previous
> >>>   version.
> >>> - struct v4l2_plane_ext_pix_format removed, using struct
> >>> v4l2_plane_pix_format instead (Tomasz)
> >>> - refer to drm_fourcc.h in struct v4l2_ext_pix_format docs (Hans)
> >>> - reorder colorimetry fields in struct v4l2_ext_pix_format (Hans)
> >>> - do not set Ext ioctls as valid for vid_out_overlay (Tomasz)
> >>> - refactor conversion functions, so planes are color planes (Tomasz)
> >>> - Don't explicitly check for e->modifier != 0 in
> >>> v4l2_ext_pix_format_to_format() (Tomasz)
> >>> - Use "ef" for extended formats in the framework for consistency
> >>> (Tomasz)
> >>> - Handle xfer_func field in conversions (Tomasz)
> >>> - Zero reserved fields in v4l_s_ext_pix_fmt() and
> >>> v4l_try_ext_pix_fmt() (Tomasz)
> >>> - Refactor format functions to use v4l_fmt_ioctl_via_ext()
> >>> - Several fixes/refactoring/changes
> >>> - Remove EXT API for touch devices
> >>>
> >>> Changes in v5:
> >>> - change sizes and reorder fields to avoid holes in the struct and make
> >>>    it the same for 32 and 64 bits
> >>> - removed __attribute__ ((packed)) from uapi structs
> >>> - Fix doc warning from make htmldocs
> >>> - Updated commit message with EXT_PIX prefix for the ioctls.
> >>>
> >>> Changes in v4:
> >>> - Use v4l2_ext_pix_format directly in the ioctl, drop v4l2_ext_format,
> >>> making V4L2_BUF_TYPE_VIDEO_[OUTPUT,CAPTURE] the only valid types.
> >>> - Add reserved fields
> >>> - Removed num_planes from struct v4l2_ext_pix_format
> >>> - Removed flag field from struct v4l2_ext_pix_format, since the only
> >>>    defined value is V4L2_PIX_FMT_FLAG_PREMUL_ALPHA only used by vsp1,
> >>>    where we can use modifiers, or add it back later through the reserved
> >>>    bits.
> >>> - In v4l2_ext_format_to_format(), check if modifier is != MOD_LINEAR &&
> >>>    != MOD_INVALID
> >>> - Fix type assignment in v4l_g_fmt_ext_pix()
> >>> - Rebased on top of media/master (post 5.8-rc1)
> >>>
> >>> Changes in v3:
> >>> - Rebased on top of media/master (post 5.4-rc1)
> >>>
> >>> Changes in v2:
> >>> - Move the modifier in v4l2_ext_format (was formerly placed in
> >>>    v4l2_ext_plane)
> >>> - Fix a few bugs in the converters and add a strict parameter to
> >>>    allow conversion of uninitialized/mis-initialized objects
> >>> ---
> >>>   drivers/media/v4l2-core/v4l2-dev.c   |  27 +-
> >>>   drivers/media/v4l2-core/v4l2-ioctl.c | 538 +++++++++++++++++++++++++--
> >>>   include/media/v4l2-ioctl.h           |  28 ++
> >>>   include/uapi/linux/videodev2.h       |  41 ++
> >>>   4 files changed, 602 insertions(+), 32 deletions(-)
> >>>
> >>> diff --git a/drivers/media/v4l2-core/v4l2-dev.c
> >>> b/drivers/media/v4l2-core/v4l2-dev.c
> >>> index f9cff033d0dc..5add58cb6d45 100644
> >>> --- a/drivers/media/v4l2-core/v4l2-dev.c
> >>> +++ b/drivers/media/v4l2-core/v4l2-dev.c
> >>> @@ -608,27 +608,42 @@ static void determine_valid_ioctls(struct
> >>> video_device *vdev)
> >>>                      ops->vidioc_enum_fmt_vid_overlay)) ||
> >>>               (is_tx && ops->vidioc_enum_fmt_vid_out))
> >>>               set_bit(_IOC_NR(VIDIOC_ENUM_FMT), valid_ioctls);
> >>> +        if ((is_rx && ops->vidioc_g_fmt_vid_overlay) ||
> >>> +            (is_tx && ops->vidioc_g_fmt_vid_out_overlay))
> >>> +             set_bit(_IOC_NR(VIDIOC_G_FMT), valid_ioctls);
> >>>           if ((is_rx && (ops->vidioc_g_fmt_vid_cap ||
> >>>                      ops->vidioc_g_fmt_vid_cap_mplane ||
> >>> -                   ops->vidioc_g_fmt_vid_overlay)) ||
> >>> +                   ops->vidioc_g_ext_pix_fmt_vid_cap)) ||
> >>>               (is_tx && (ops->vidioc_g_fmt_vid_out ||
> >>>                      ops->vidioc_g_fmt_vid_out_mplane ||
> >>> -                   ops->vidioc_g_fmt_vid_out_overlay)))
> >>> +                   ops->vidioc_g_ext_pix_fmt_vid_out))) {
> >>>                set_bit(_IOC_NR(VIDIOC_G_FMT), valid_ioctls);
> >>> +             set_bit(_IOC_NR(VIDIOC_G_EXT_PIX_FMT), valid_ioctls);
> >>> +        }
> >>> +        if ((is_rx && ops->vidioc_s_fmt_vid_overlay) ||
> >>> +            (is_tx && ops->vidioc_s_fmt_vid_out_overlay))
> >>> +             set_bit(_IOC_NR(VIDIOC_S_FMT), valid_ioctls);
> >>>           if ((is_rx && (ops->vidioc_s_fmt_vid_cap ||
> >>>                      ops->vidioc_s_fmt_vid_cap_mplane ||
> >>> -                   ops->vidioc_s_fmt_vid_overlay)) ||
> >>> +                   ops->vidioc_s_ext_pix_fmt_vid_cap)) ||
> >>>               (is_tx && (ops->vidioc_s_fmt_vid_out ||
> >>>                      ops->vidioc_s_fmt_vid_out_mplane ||
> >>> -                   ops->vidioc_s_fmt_vid_out_overlay)))
> >>> +                   ops->vidioc_s_ext_pix_fmt_vid_out))) {
> >>>                set_bit(_IOC_NR(VIDIOC_S_FMT), valid_ioctls);
> >>> +             set_bit(_IOC_NR(VIDIOC_S_EXT_PIX_FMT), valid_ioctls);
> >>> +        }
> >>> +        if ((is_rx && ops->vidioc_try_fmt_vid_overlay) ||
> >>> +            (is_tx && ops->vidioc_try_fmt_vid_out_overlay))
> >>> +             set_bit(_IOC_NR(VIDIOC_TRY_FMT), valid_ioctls);
> >>>           if ((is_rx && (ops->vidioc_try_fmt_vid_cap ||
> >>>                      ops->vidioc_try_fmt_vid_cap_mplane ||
> >>> -                   ops->vidioc_try_fmt_vid_overlay)) ||
> >>> +                   ops->vidioc_try_ext_pix_fmt_vid_cap)) ||
> >>>               (is_tx && (ops->vidioc_try_fmt_vid_out ||
> >>>                      ops->vidioc_try_fmt_vid_out_mplane ||
> >>> -                   ops->vidioc_try_fmt_vid_out_overlay)))
> >>> +                   ops->vidioc_try_ext_pix_fmt_vid_out))) {
> >>>                set_bit(_IOC_NR(VIDIOC_TRY_FMT), valid_ioctls);
> >>> +             set_bit(_IOC_NR(VIDIOC_TRY_EXT_PIX_FMT), valid_ioctls);
> >>> +        }
> >>>           SET_VALID_IOCTL(ops, VIDIOC_OVERLAY, vidioc_overlay);
> >>>           SET_VALID_IOCTL(ops, VIDIOC_G_FBUF, vidioc_g_fbuf);
> >>>           SET_VALID_IOCTL(ops, VIDIOC_S_FBUF, vidioc_s_fbuf);
> >>> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c
> >>> b/drivers/media/v4l2-core/v4l2-ioctl.c
> >>> index 848286a284f6..a9c07c0a73ec 100644
> >>> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> >>> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> >>> @@ -18,6 +18,8 @@
> >>>   #include <linux/videodev2.h>
> >>> +#include <drm/drm_fourcc.h>
> >>> +
> >>>   #include <media/v4l2-common.h>
> >>>   #include <media/v4l2-ioctl.h>
> >>>   #include <media/v4l2-ctrls.h>
> >>> @@ -38,6 +40,11 @@
> >>>   #define is_valid_ioctl(vfd, cmd) test_bit(_IOC_NR(cmd),
> >>> (vfd)->valid_ioctls)
> >>> +#define V4L2_IS_CAP_MULTIPLANAR(vdev)    (vdev->device_caps & \
> >>> +                     (V4L2_CAP_VIDEO_CAPTURE_MPLANE | \
> >>> +                     V4L2_CAP_VIDEO_OUTPUT_MPLANE | \
> >>> +                     V4L2_CAP_VIDEO_M2M_MPLANE))
> >>> +
> >>>   struct std_descr {
> >>>       v4l2_std_id std;
> >>>       const char *descr;
> >>> @@ -379,6 +386,27 @@ static void v4l_print_format(const void *arg,
> >>> bool write_only)
> >>>       }
> >>>   }
> >>> +static void v4l_print_ext_pix_format(const void *arg, bool write_only)
> >>> +{
> >>> +    const struct v4l2_ext_pix_format *ef = arg;
> >>> +    unsigned int i;
> >>> +
> >>> +    pr_cont("type=%s, width=%u, height=%u, format=%c%c%c%c, modifier
> >>> %llx, field=%s, colorspace=%d, ycbcr_enc=%u, quantization=%u,
> >>> xfer_func=%u\n",
> >>> +        prt_names(ef->type, v4l2_type_names),
> >>> +        ef->width, ef->height,
> >>> +        (ef->pixelformat & 0xff),
> >>> +        (ef->pixelformat >>  8) & 0xff,
> >>> +        (ef->pixelformat >> 16) & 0xff,
> >>> +        (ef->pixelformat >> 24) & 0xff,
> >>> +        ef->modifier, prt_names(ef->field, v4l2_field_names),
> >>> +        ef->colorspace, ef->ycbcr_enc,
> >>> +        ef->quantization, ef->xfer_func);
> >>> +    for (i = 0; i < VIDEO_MAX_PLANES && ef->plane_fmt[i].sizeimage;
> >>> i++)
> >>> +        pr_debug("plane %u: bytesperline=%u sizeimage=%u\n",
> >>> +             i, ef->plane_fmt[i].bytesperline,
> >>> +             ef->plane_fmt[i].sizeimage);
> >>> +}
> >>> +
> >>>   static void v4l_print_framebuffer(const void *arg, bool write_only)
> >>>   {
> >>>       const struct v4l2_framebuffer *p = arg;
> >>> @@ -963,11 +991,15 @@ static int check_fmt(struct file *file, enum
> >>> v4l2_buf_type type)
> >>>       switch (type) {
> >>>       case V4L2_BUF_TYPE_VIDEO_CAPTURE:
> >>>           if ((is_vid || is_tch) && is_rx &&
> >>> -            (ops->vidioc_g_fmt_vid_cap ||
> >>> ops->vidioc_g_fmt_vid_cap_mplane))
> >>> +            (ops->vidioc_g_fmt_vid_cap ||
> >>> +             ops->vidioc_g_ext_pix_fmt_vid_cap ||
> >>> +             ops->vidioc_g_fmt_vid_cap_mplane))
> >>>               return 0;
> >>>           break;
> >>>       case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
> >>> -        if ((is_vid || is_tch) && is_rx &&
> >>> ops->vidioc_g_fmt_vid_cap_mplane)
> >>> +        if ((is_vid || is_tch) && is_rx &&
> >>> +            (ops->vidioc_g_fmt_vid_cap_mplane ||
> >>> +             ops->vidioc_g_ext_pix_fmt_vid_cap))
> >>>               return 0;
> >>>           break;
> >>>       case V4L2_BUF_TYPE_VIDEO_OVERLAY:
> >>> @@ -976,11 +1008,15 @@ static int check_fmt(struct file *file, enum
> >>> v4l2_buf_type type)
> >>>           break;
> >>>       case V4L2_BUF_TYPE_VIDEO_OUTPUT:
> >>>           if (is_vid && is_tx &&
> >>> -            (ops->vidioc_g_fmt_vid_out ||
> >>> ops->vidioc_g_fmt_vid_out_mplane))
> >>> +            (ops->vidioc_g_fmt_vid_out ||
> >>> +             ops->vidioc_g_ext_pix_fmt_vid_out ||
> >>> +             ops->vidioc_g_fmt_vid_out_mplane))
> >>>               return 0;
> >>>           break;
> >>>       case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
> >>> -        if (is_vid && is_tx && ops->vidioc_g_fmt_vid_out_mplane)
> >>> +        if (is_vid && is_tx &&
> >>> +            (ops->vidioc_g_ext_pix_fmt_vid_out ||
> >>> +             ops->vidioc_g_fmt_vid_out_mplane))
> >>>               return 0;
> >>>           break;
> >>>       case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY:
> >>> @@ -1060,6 +1096,204 @@ static void v4l_sanitize_format(struct
> >>> v4l2_format *fmt)
> >>>              sizeof(fmt->fmt.pix) - offset);
> >>>   }
> >>> +static void
> >>> +v4l2_ext_pix_format_to_pix_format(const struct v4l2_ext_pix_format *ef,
> >>> +                  struct v4l2_pix_format *pix)
> >>> +{
> >>> +    unsigned int i;
> >>> +
> >>> +    pix->width = ef->width;
> >>> +    pix->height = ef->height;
> >>> +    pix->field = ef->field;
> >>> +    pix->flags = V4L2_PIX_FMT_FLAG_SET_CSC;
> >>> +    pix->colorspace = ef->colorspace;
> >>> +    pix->ycbcr_enc = ef->ycbcr_enc;
> >>> +    pix->priv = V4L2_PIX_FMT_PRIV_MAGIC;
> >>> +    pix->quantization = ef->quantization;
> >>> +    pix->pixelformat = ef->pixelformat;
> >>> +    pix->bytesperline = ef->plane_fmt[0].bytesperline;
> >>> +    pix->sizeimage = ef->plane_fmt[0].sizeimage;
> >>> +    for (i = 1; i < VIDEO_MAX_PLANES && ef->plane_fmt[i].sizeimage;
> >>> i++)
> >>> +        pix->sizeimage += ef->plane_fmt[i].sizeimage;
> >>> +}
> >>> +
> >>> +static void
> >>> +v4l2_ext_pix_format_to_pix_mp_format(const struct
> >>> v4l2_ext_pix_format *ef,
> >>> +                     struct v4l2_pix_format_mplane *pix_mp)
> >>> +{
> >>> +    const struct v4l2_format_info *info =
> >>> +                    v4l2_format_info(ef->pixelformat);
> >>> +    unsigned int i;
> >>> +
> >>> +    pix_mp->width = ef->width;
> >>> +    pix_mp->height = ef->height;
> >>> +    pix_mp->field = ef->field;
> >>> +    pix_mp->flags = V4L2_PIX_FMT_FLAG_SET_CSC;
> >>> +    pix_mp->colorspace = ef->colorspace;
> >>> +    pix_mp->ycbcr_enc = ef->ycbcr_enc;
> >>> +    pix_mp->quantization = ef->quantization;
> >>> +    pix_mp->pixelformat = ef->pixelformat;
> >>> +
> >>> +    /* This is true when converting to non-M-variant */
> >>> +    if (info && info->mem_planes == 1) {
> >>> +        pix_mp->plane_fmt[0] = ef->plane_fmt[0];
> >>> +        pix_mp->num_planes = 1;
> >>> +        for (i = 1; i < VIDEO_MAX_PLANES &&
> >>> ef->plane_fmt[i].sizeimage; i++)
> >>> +            pix_mp->plane_fmt[0].sizeimage +=
> >>> ef->plane_fmt[i].sizeimage;
> >>> +
> >>> +        return;
> >>> +    }
> >>> +
> >>> +    for (i = 0; i < VIDEO_MAX_PLANES && ef->plane_fmt[i].sizeimage;
> >>> i++)
> >>> +        pix_mp->plane_fmt[i] = ef->plane_fmt[i];
> >>> +    pix_mp->num_planes = i;
> >>> +}
> >>> +
> >>> +/*
> >>> + * v4l2_ext_pix_format_to_format - convert to v4l2_ext_pix_format to
> >>> v4l2_format
> >>> + *
> >>> + * @ef: A pointer to struct struct v4l2_ext_pix_format to be converted.
> >>> + * @f: A pointer to struct v4l2_format to be filled.
> >>> + * @is_mplane: Bool indicating if multiplanar API should be used in @f.
> >>> + *
> >>> + * If pixelformat should be converted to M-variant, change
> >>> ef->pixelformat
> >>> + * to the M-variant before calling this function.
> >>> + */
> >>> +static void v4l2_ext_pix_format_to_format(const struct
> >>> v4l2_ext_pix_format *ef,
> >>> +                      struct v4l2_format *f, bool is_mplane)
> >>> +{
> >>> +    memset(f, 0, sizeof(*f));
> >>> +
> >>> +    if (ef->modifier != DRM_FORMAT_MOD_LINEAR &&
> >>> +        ef->modifier != DRM_FORMAT_MOD_INVALID)
> >>> +        pr_warn("Modifiers are not supported in v4l2_format,
> >>> ignoring %llx\n",
> >>> +            ef->modifier);
> >>> +
> >>> +    if (!is_mplane) {
> >>> +        f->type = ef->type;
> >>> +        v4l2_ext_pix_format_to_pix_format(ef, &f->fmt.pix);
> >>> +        return;
> >>> +    }
> >>> +
> >>> +    if (ef->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
> >>> +        f->type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
> >>> +    else
> >>> +        f->type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
> >>> +
> >>> +    v4l2_ext_pix_format_to_pix_mp_format(ef, &f->fmt.pix_mp);
> >>> +}
> >>> +
> >>> +static void
> >>> +v4l2_pix_format_to_ext_pix_format(const struct v4l2_pix_format *pix,
> >>> +                  struct v4l2_ext_pix_format *ef)
> >>> +{
> >>> +    const struct v4l2_format_info *info =
> >>> +                    v4l2_format_info(pix->pixelformat);
> >>> +    unsigned int i;
> >>> +
> >>> +    ef->width = pix->width;
> >>> +    ef->height = pix->height;
> >>> +    ef->field = pix->field;
> >>> +    ef->colorspace = pix->colorspace;
> >>> +    ef->ycbcr_enc = pix->ycbcr_enc;
> >>> +    ef->quantization = pix->quantization;
> >>> +    ef->xfer_func = pix->xfer_func;
> >>> +    if (pix->flags)
> >>> +        pr_warn("Ignoring pixelformat flags 0x%x\n", pix->flags);
> >>> +
> >>> +    /* We assume M-variants won't be used in this function */
> >>> +    ef->pixelformat = pix->pixelformat;
> >>> +
> >>> +    ef->plane_fmt[0].bytesperline = pix->bytesperline;
> >>> +    ef->plane_fmt[0].sizeimage = pix->sizeimage;
> >>> +
> >>> +    if (!info)
> >>> +        return;
> >>> +
> >>> +    for (i = 1; i < info->comp_planes; i++) {
> >>> +        ef->plane_fmt[i].bytesperline = pix->bytesperline / info->hdiv;
> >>> +        ef->plane_fmt[i].sizeimage = ef->plane_fmt[i].bytesperline *
> >>> +                         ef->height / info->vdiv;
> >>> +        ef->plane_fmt[0].sizeimage -= ef->plane_fmt[i].sizeimage;
> >>> +    }
> >>> +}
> >>> +
> >>> +static void
> >>> +v4l2_pix_mp_format_to_ext_pix_format(const struct
> >>> v4l2_pix_format_mplane *pix_mp,
> >>> +                     struct v4l2_ext_pix_format *ef)
> >>> +{
> >>> +    const struct v4l2_format_info *info =
> >>> +                    v4l2_format_info(pix_mp->pixelformat);
> >>> +    unsigned int i;
> >>> +
> >>> +    ef->width = pix_mp->width;
> >>> +    ef->height = pix_mp->height;
> >>> +    ef->field = pix_mp->field;
> >>> +    ef->colorspace = pix_mp->colorspace;
> >>> +    ef->ycbcr_enc = pix_mp->ycbcr_enc;
> >>> +    ef->quantization = pix_mp->quantization;
> >>> +    ef->xfer_func = pix_mp->xfer_func;
> >>> +    if (pix_mp->flags)
> >>> +        pr_warn("Ignoring pixelformat flags 0x%x\n", pix_mp->flags);
> >>> +
> >>> +    if (!info)
> >>> +        return;
> >>> +
> >>> +    ef->pixelformat = info && info->norm ?
> >>
> >> 'info &&' can be dropped, info is always non-NULL here.
> >>
> >>> +              info->norm : pix_mp->pixelformat;
> >>> +
> >>> +    if (info->comp_planes == info->mem_planes) {
> >>> +        for (i = 0; i < pix_mp->num_planes && i < VIDEO_MAX_PLANES;
> >>> i++)
> >>> +            ef->plane_fmt[i] = pix_mp->plane_fmt[i];
> >>> +
> >>> +        return;
> >>> +    }
> >>> +
> >>> +    /* case where mem_planes is 1 and comp_planes > 1 */
> >>> +    ef->plane_fmt[0] = pix_mp->plane_fmt[0];
> >>> +    for (i = 1; i < info->comp_planes; i++) {
> >>> +        ef->plane_fmt[i].bytesperline =
> >>> +            pix_mp->plane_fmt[0].bytesperline / info->hdiv;
> >>> +        ef->plane_fmt[i].sizeimage =
> >>> +            ef->plane_fmt[i].bytesperline * ef->height / info->vdiv;
> >>> +        ef->plane_fmt[0].sizeimage -= ef->plane_fmt[i].sizeimage;
> >>> +    }
> >>> +}
> >>> +
> >>> +/*
> >>> + * v4l2_format_to_ext_pix_format - convert to v4l2_format to
> >>> v4l2_ext_pix_format
> >>> + *
> >>> + * @f: A pointer to struct v4l2_format to be converted.
> >>> + * @ef: A pointer to struct struct v4l2_ext_pix_format to be filled.
> >>> + *
> >>> + * This method normalize the pixelformat to non-M variant.
> >>> + */
> >>> +static void v4l2_format_to_ext_pix_format(const struct v4l2_format *f,
> >>> +                      struct v4l2_ext_pix_format *ef)
> >>> +{
> >>> +    memset(ef, 0, sizeof(*ef));
> >>> +
> >>> +    switch (f->type) {
> >>> +    case V4L2_BUF_TYPE_VIDEO_CAPTURE:
> >>> +    case V4L2_BUF_TYPE_VIDEO_OUTPUT:
> >>> +        ef->type = f->type;
> >>> +        v4l2_pix_format_to_ext_pix_format(&f->fmt.pix, ef);
> >>> +        break;
> >>> +    case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
> >>> +        ef->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> >>> +        v4l2_pix_mp_format_to_ext_pix_format(&f->fmt.pix_mp, ef);
> >>> +        break;
> >>> +    case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
> >>> +        ef->type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
> >>> +        v4l2_pix_mp_format_to_ext_pix_format(&f->fmt.pix_mp, ef);
> >>> +        break;
> >>> +    default:
> >>> +        WARN("Converting to Ext Pix Format with wrong buffer type
> >>> %s\n",
> >>> +             prt_names(f->type, v4l2_type_names));
> >>> +        break;
> >>> +    }
> >>> +}
> >>> +
> >>>   static int v4l_querycap(const struct v4l2_ioctl_ops *ops,
> >>>                   struct file *file, void *fh, void *arg)
> >>>   {
> >>> @@ -1565,6 +1799,100 @@ static void v4l_pix_format_touch(struct
> >>> v4l2_pix_format *p)
> >>>       p->xfer_func = 0;
> >>>   }
> >>> +static int v4l_fmt_ioctl_via_ext(const struct v4l2_ioctl_ops *ops,
> >>> +                 struct file *file, void *fh,
> >>> +                 struct v4l2_format *f,
> >>> +                 unsigned int ioctl)
> >>> +{
> >>> +    bool is_multiplanar = V4L2_TYPE_IS_MULTIPLANAR(f->type);
> >>> +    struct video_device *vdev = video_devdata(file);
> >>> +    struct v4l2_ext_pix_format ef = {0};
> >>> +    u32 original_pixfmt = 0;
> >>> +    u32 cap_mask;
> >>> +    int ret;
> >>> +
> >>> +    if (ioctl != VIDIOC_G_FMT) {
> >>> +        /*
> >>> +         * If CSC attributes are read only, set them to DEFAULT
> >>> +         * to avoid changes by the driver.
> >>> +         */
> >>> +        if (is_multiplanar) {
> >>> +            if (!(f->fmt.pix_mp.flags & V4L2_PIX_FMT_FLAG_SET_CSC)) {
> >>> +                f->fmt.pix_mp.colorspace = V4L2_COLORSPACE_DEFAULT;
> >>> +                f->fmt.pix_mp.ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT;
> >>> +                f->fmt.pix_mp.quantization = V4L2_QUANTIZATION_DEFAULT;
> >>> +                f->fmt.pix_mp.xfer_func = V4L2_XFER_FUNC_DEFAULT;
> >>> +            }
> >>> +            /* Unset the flag to avoid warning in the convertion */
> >>> +            f->fmt.pix_mp.flags &= ~V4L2_PIX_FMT_FLAG_SET_CSC;
> >>> +
> >>> +            /* Save pixelformat in case M-variant is being used */
> >>> +            original_pixfmt = f->fmt.pix_mp.pixelformat;
> >>> +        } else {
> >>> +            if (!(f->fmt.pix.flags & V4L2_PIX_FMT_FLAG_SET_CSC)) {
> >>> +                f->fmt.pix.colorspace = V4L2_COLORSPACE_DEFAULT;
> >>> +                f->fmt.pix.ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT;
> >>> +                f->fmt.pix.quantization = V4L2_QUANTIZATION_DEFAULT;
> >>> +                f->fmt.pix.xfer_func = V4L2_XFER_FUNC_DEFAULT;
> >>> +            }
> >>> +            /* Unset the flag to avoid warning in the convertion */
> >>> +            f->fmt.pix.flags &= ~V4L2_PIX_FMT_FLAG_SET_CSC;
> >>> +        }
> >>> +        v4l2_format_to_ext_pix_format(f, &ef);
> >>> +    }
> >>> +
> >>> +    switch (f->type) {
> >>> +    case V4L2_BUF_TYPE_VIDEO_CAPTURE:
> >>> +    case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
> >>> +        cap_mask = V4L2_CAP_VIDEO_CAPTURE_MPLANE |
> >>> +               V4L2_CAP_VIDEO_M2M_MPLANE;
> >>> +        if (!!(vdev->device_caps & cap_mask) !=
> >>> +            (f->type == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE))
> >>> +            return -EINVAL;
> >>> +
> >>> +        ef.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> >>> +        if (ioctl == VIDIOC_G_FMT)
> >>> +            ret = ops->vidioc_g_ext_pix_fmt_vid_cap(file, fh, &ef);
> >>> +        else if (ioctl == VIDIOC_S_FMT)
> >>> +            ret = ops->vidioc_s_ext_pix_fmt_vid_cap(file, fh, &ef);
> >>> +        else
> >>> +            ret = ops->vidioc_try_ext_pix_fmt_vid_cap(file, fh,
> >>> +                                  &ef);
> >>> +        break;
> >>> +
> >>> +    case V4L2_BUF_TYPE_VIDEO_OUTPUT:
> >>> +    case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
> >>> +        cap_mask = V4L2_CAP_VIDEO_OUTPUT_MPLANE |
> >>> +               V4L2_CAP_VIDEO_M2M_MPLANE;
> >>> +        if (!!(vdev->device_caps & cap_mask) !=
> >>> +            (f->type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE))
> >>> +            return -EINVAL;
> >>> +
> >>> +        ef.type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
> >>> +        if (ioctl == VIDIOC_G_FMT)
> >>> +            ret = ops->vidioc_g_ext_pix_fmt_vid_out(file, fh, &ef);
> >>> +        else if (ioctl == VIDIOC_S_FMT)
> >>> +            ret = ops->vidioc_s_ext_pix_fmt_vid_out(file, fh, &ef);
> >>> +        else
> >>> +            ret = ops->vidioc_try_ext_pix_fmt_vid_out(file, fh,
> >>> +                                  &ef);
> >>> +        break;
> >>> +
> >>> +    default:
> >>> +        return -EINVAL;
> >>> +    }
> >>> +
> >>> +    if (ret)
> >>> +        return ret;
> >>> +
> >>> +    if (original_pixfmt != ef.pixelformat &&
> >>> +        v4l2_format_info(original_pixfmt))
> >>
> >> Could this test be simplified to: 'if (original_pixfmt)'?
> >>
> >> I.e., if the original pixfmt was saved, then restore it here.
> >>
> >>> +        ef.pixelformat = original_pixfmt;
> >>> +
> >>> +    v4l2_ext_pix_format_to_format(&ef, f, is_multiplanar);
> >>> +    return 0;
> >>> +}
> >>> +
> >>>   static int v4l_g_fmt(const struct v4l2_ioctl_ops *ops,
> >>>                   struct file *file, void *fh, void *arg)
> >>>   {
> >>> @@ -1601,17 +1929,26 @@ static int v4l_g_fmt(const struct
> >>> v4l2_ioctl_ops *ops,
> >>>       switch (p->type) {
> >>>       case V4L2_BUF_TYPE_VIDEO_CAPTURE:
> >>> -        if (unlikely(!ops->vidioc_g_fmt_vid_cap))
> >>> +        if (unlikely(!ops->vidioc_g_fmt_vid_cap &&
> >>> +                 !ops->vidioc_g_ext_pix_fmt_vid_cap))
> >>>               break;
> >>>           p->fmt.pix.priv = V4L2_PIX_FMT_PRIV_MAGIC;
> >>> -        ret = ops->vidioc_g_fmt_vid_cap(file, fh, arg);
> >>> +        ret = ops->vidioc_g_fmt_vid_cap ?
> >>> +              ops->vidioc_g_fmt_vid_cap(file, fh, arg) :
> >>> +              v4l_fmt_ioctl_via_ext(ops, file, fh, arg,
> >>> +                        VIDIOC_G_FMT);
> >>>           /* just in case the driver zeroed it again */
> >>>           p->fmt.pix.priv = V4L2_PIX_FMT_PRIV_MAGIC;
> >>>           if (vfd->vfl_type == VFL_TYPE_TOUCH)
> >>>               v4l_pix_format_touch(&p->fmt.pix);
> >>>           return ret;
> >>>       case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
> >>> -        return ops->vidioc_g_fmt_vid_cap_mplane(file, fh, arg);
> >>> +        if (ops->vidioc_g_fmt_vid_cap_mplane)
> >>> +            return ops->vidioc_g_fmt_vid_cap_mplane(file, fh, arg);
> >>> +        else if (ops->vidioc_g_ext_pix_fmt_vid_cap)
> >>
> >> 'else' can be dropped.
> >>
> >>> +            return v4l_fmt_ioctl_via_ext(ops, file, fh, arg,
> >>> +                             VIDIOC_G_FMT);
> >>> +        break;
> >>>       case V4L2_BUF_TYPE_VIDEO_OVERLAY:
> >>>           return ops->vidioc_g_fmt_vid_overlay(file, fh, arg);
> >>>       case V4L2_BUF_TYPE_VBI_CAPTURE:
> >>> @@ -1619,15 +1956,23 @@ static int v4l_g_fmt(const struct
> >>> v4l2_ioctl_ops *ops,
> >>>       case V4L2_BUF_TYPE_SLICED_VBI_CAPTURE:
> >>>           return ops->vidioc_g_fmt_sliced_vbi_cap(file, fh, arg);
> >>>       case V4L2_BUF_TYPE_VIDEO_OUTPUT:
> >>> -        if (unlikely(!ops->vidioc_g_fmt_vid_out))
> >>> +        if (unlikely(!ops->vidioc_g_fmt_vid_out &&
> >>> +                 !ops->vidioc_g_ext_pix_fmt_vid_out))
> >>>               break;
> >>>           p->fmt.pix.priv = V4L2_PIX_FMT_PRIV_MAGIC;
> >>> -        ret = ops->vidioc_g_fmt_vid_out(file, fh, arg);
> >>> +        ret = ops->vidioc_g_fmt_vid_out ?
> >>> +              ops->vidioc_g_fmt_vid_out(file, fh, arg) :
> >>> +              v4l_fmt_ioctl_via_ext(ops, file, fh, arg, VIDIOC_G_FMT);
> >>>           /* just in case the driver zeroed it again */
> >>>           p->fmt.pix.priv = V4L2_PIX_FMT_PRIV_MAGIC;
> >>>           return ret;
> >>>       case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
> >>> -        return ops->vidioc_g_fmt_vid_out_mplane(file, fh, arg);
> >>> +        if (ops->vidioc_g_fmt_vid_out_mplane)
> >>> +            return ops->vidioc_g_fmt_vid_out_mplane(file, fh, arg);
> >>> +        else if (ops->vidioc_g_ext_pix_fmt_vid_out)
> >>
> >> Ditto.
> >>
> >>> +            return v4l_fmt_ioctl_via_ext(ops, file, fh, arg,
> >>> +                             VIDIOC_G_FMT);
> >>> +        break;
> >>>       case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY:
> >>>           return ops->vidioc_g_fmt_vid_out_overlay(file, fh, arg);
> >>>       case V4L2_BUF_TYPE_VBI_OUTPUT:
> >>> @@ -1646,6 +1991,42 @@ static int v4l_g_fmt(const struct
> >>> v4l2_ioctl_ops *ops,
> >>>       return -EINVAL;
> >>>   }
> >>> +static int v4l_g_ext_pix_fmt(const struct v4l2_ioctl_ops *ops,
> >>> +                 struct file *file, void *fh, void *arg)
> >>> +{
> >>> +    struct v4l2_ext_pix_format *ef = arg;
> >>> +    struct v4l2_format f = {
> >>> +        .type = ef->type,
> >>> +    };
> >>> +    int ret = check_fmt(file, ef->type);
> >>> +
> >>> +    if (ret)
> >>> +        return ret;
> >>> +
> >>> +    memset(ef, 0, sizeof(*ef));
> >>> +    ef->type = f.type;
> >>> +
> >>> +    switch (f.type) {
> >>> +    case V4L2_BUF_TYPE_VIDEO_CAPTURE:
> >>> +        if (ops->vidioc_g_ext_pix_fmt_vid_cap)
> >>> +            return ops->vidioc_g_ext_pix_fmt_vid_cap(file, fh, ef);
> >>> +        break;
> >>> +    case V4L2_BUF_TYPE_VIDEO_OUTPUT:
> >>> +        if (ops->vidioc_g_ext_pix_fmt_vid_out)
> >>> +            return ops->vidioc_g_ext_pix_fmt_vid_out(file, fh, ef);
> >>> +        break;
> >>> +    default:
> >>> +        return -EINVAL;
> >>> +    }
> >>> +
> >>> +    ret = v4l_g_fmt(ops, file, fh, &f);
> >>> +    if (ret)
> >>> +        return ret;
> >>> +
> >>> +    v4l2_format_to_ext_pix_format(&f, ef);
> >>> +    return 0;
> >>> +}
> >>> +
> >>>   static int v4l_s_fmt(const struct v4l2_ioctl_ops *ops,
> >>>                   struct file *file, void *fh, void *arg)
> >>>   {
> >>> @@ -1664,23 +2045,29 @@ static int v4l_s_fmt(const struct
> >>> v4l2_ioctl_ops *ops,
> >>>       switch (p->type) {
> >>>       case V4L2_BUF_TYPE_VIDEO_CAPTURE:
> >>> -        if (unlikely(!ops->vidioc_s_fmt_vid_cap))
> >>> +        if (unlikely(!ops->vidioc_s_fmt_vid_cap &&
> >>> +                 !ops->vidioc_s_ext_pix_fmt_vid_cap))
> >>>               break;
> >>>           CLEAR_AFTER_FIELD(p, fmt.pix);
> >>> -        ret = ops->vidioc_s_fmt_vid_cap(file, fh, arg);
> >>> +        ret = ops->vidioc_s_fmt_vid_cap ?
> >>> +              ops->vidioc_s_fmt_vid_cap(file, fh, arg) :
> >>> +              v4l_fmt_ioctl_via_ext(ops, file, fh, arg, VIDIOC_S_FMT);
> >>>           /* just in case the driver zeroed it again */
> >>>           p->fmt.pix.priv = V4L2_PIX_FMT_PRIV_MAGIC;
> >>>           if (vfd->vfl_type == VFL_TYPE_TOUCH)
> >>>               v4l_pix_format_touch(&p->fmt.pix);
> >>>           return ret;
> >>>       case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
> >>> -        if (unlikely(!ops->vidioc_s_fmt_vid_cap_mplane))
> >>> +        if (unlikely(!ops->vidioc_s_fmt_vid_cap_mplane &&
> >>> +                 !ops->vidioc_s_ext_pix_fmt_vid_cap))
> >>>               break;
> >>>           CLEAR_AFTER_FIELD(p, fmt.pix_mp.xfer_func);
> >>>           for (i = 0; i < p->fmt.pix_mp.num_planes; i++)
> >>>               CLEAR_AFTER_FIELD(&p->fmt.pix_mp.plane_fmt[i],
> >>>                         bytesperline);
> >>> -        return ops->vidioc_s_fmt_vid_cap_mplane(file, fh, arg);
> >>> +        return ops->vidioc_s_fmt_vid_cap_mplane ?
> >>> +               ops->vidioc_s_fmt_vid_cap_mplane(file, fh, arg) :
> >>> +               v4l_fmt_ioctl_via_ext(ops, file, fh, arg,
> >>> VIDIOC_S_FMT);
> >>>       case V4L2_BUF_TYPE_VIDEO_OVERLAY:
> >>>           if (unlikely(!ops->vidioc_s_fmt_vid_overlay))
> >>>               break;
> >>> @@ -1697,21 +2084,27 @@ static int v4l_s_fmt(const struct
> >>> v4l2_ioctl_ops *ops,
> >>>           CLEAR_AFTER_FIELD(p, fmt.sliced.io_size);
> >>>           return ops->vidioc_s_fmt_sliced_vbi_cap(file, fh, arg);
> >>>       case V4L2_BUF_TYPE_VIDEO_OUTPUT:
> >>> -        if (unlikely(!ops->vidioc_s_fmt_vid_out))
> >>> +        if (unlikely(!ops->vidioc_s_fmt_vid_out &&
> >>> +                 !ops->vidioc_s_ext_pix_fmt_vid_out))
> >>>               break;
> >>>           CLEAR_AFTER_FIELD(p, fmt.pix);
> >>> -        ret = ops->vidioc_s_fmt_vid_out(file, fh, arg);
> >>> +        ret = ops->vidioc_s_fmt_vid_out ?
> >>> +              ops->vidioc_s_fmt_vid_out(file, fh, arg) :
> >>> +              v4l_fmt_ioctl_via_ext(ops, file, fh, arg, VIDIOC_S_FMT);
> >>>           /* just in case the driver zeroed it again */
> >>>           p->fmt.pix.priv = V4L2_PIX_FMT_PRIV_MAGIC;
> >>>           return ret;
> >>>       case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
> >>> -        if (unlikely(!ops->vidioc_s_fmt_vid_out_mplane))
> >>> +        if (unlikely(!ops->vidioc_s_fmt_vid_out_mplane &&
> >>> +                 !ops->vidioc_s_ext_pix_fmt_vid_out))
> >>>               break;
> >>>           CLEAR_AFTER_FIELD(p, fmt.pix_mp.xfer_func);
> >>>           for (i = 0; i < p->fmt.pix_mp.num_planes; i++)
> >>>               CLEAR_AFTER_FIELD(&p->fmt.pix_mp.plane_fmt[i],
> >>>                         bytesperline);
> >>> -        return ops->vidioc_s_fmt_vid_out_mplane(file, fh, arg);
> >>> +        return ops->vidioc_s_fmt_vid_out_mplane ?
> >>> +               ops->vidioc_s_fmt_vid_out_mplane(file, fh, arg) :
> >>> +               v4l_fmt_ioctl_via_ext(ops, file, fh, arg, VIDIOC_S_FMT);
> >>>       case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY:
> >>>           if (unlikely(!ops->vidioc_s_fmt_vid_out_overlay))
> >>>               break;
> >>> @@ -1751,6 +2144,43 @@ static int v4l_s_fmt(const struct
> >>> v4l2_ioctl_ops *ops,
> >>>       return -EINVAL;
> >>>   }
> >>> +static int v4l_s_ext_pix_fmt(const struct v4l2_ioctl_ops *ops,
> >>> +                 struct file *file, void *fh, void *arg)
> >>> +{
> >>> +    struct video_device *vfd = video_devdata(file);
> >>> +    struct v4l2_ext_pix_format *ef = arg;
> >>> +    struct v4l2_format f;
> >>> +    int ret = check_fmt(file, ef->type);
> >>> +
> >>> +    if (ret)
> >>> +        return ret;
> >>> +
> >>> +    memset(ef->reserved, 0, sizeof(ef->reserved));
> >>> +
> >>> +    switch (ef->type) {
> >>> +    case V4L2_BUF_TYPE_VIDEO_CAPTURE:
> >>> +        if (ops->vidioc_s_ext_pix_fmt_vid_cap)
> >>> +            return ops->vidioc_s_ext_pix_fmt_vid_cap(file, fh, ef);
> >>> +        break;
> >>> +    case V4L2_BUF_TYPE_VIDEO_OUTPUT:
> >>> +        if (ops->vidioc_s_ext_pix_fmt_vid_out)
> >>> +            return ops->vidioc_s_ext_pix_fmt_vid_out(file, fh, ef);
> >>> +        break;
> >>> +    default:
> >>> +        return -EINVAL;
> >>> +    }
> >>> +
> >>> +    v4l2_ext_pix_format_to_format(ef, &f,
> >>> V4L2_IS_CAP_MULTIPLANAR(vfd));
> >>> +
> >>> +    ret = v4l_s_fmt(ops, file, fh, &f);
> >>> +    if (ret)
> >>> +        /* TODO: retry with M-variant of ef->pixelformat? */
> >>
> >> See my comments on this at the top.
> >>
> >>> +        return ret;
> >>> +
> >>> +    v4l2_format_to_ext_pix_format(&f, ef);
> >>> +    return 0;
> >>> +}
> >>> +
> >>>   static int v4l_try_fmt(const struct v4l2_ioctl_ops *ops,
> >>>                   struct file *file, void *fh, void *arg)
> >>>   {
> >>> @@ -1766,23 +2196,30 @@ static int v4l_try_fmt(const struct
> >>> v4l2_ioctl_ops *ops,
> >>>       switch (p->type) {
> >>>       case V4L2_BUF_TYPE_VIDEO_CAPTURE:
> >>> -        if (unlikely(!ops->vidioc_try_fmt_vid_cap))
> >>> +        if (unlikely(!ops->vidioc_try_fmt_vid_cap &&
> >>> +                 !ops->vidioc_try_ext_pix_fmt_vid_cap))
> >>>               break;
> >>>           CLEAR_AFTER_FIELD(p, fmt.pix);
> >>> -        ret = ops->vidioc_try_fmt_vid_cap(file, fh, arg);
> >>> +        ret = ops->vidioc_try_fmt_vid_cap ?
> >>> +              ops->vidioc_try_fmt_vid_cap(file, fh, arg) :
> >>> +              v4l_fmt_ioctl_via_ext(ops, file, fh, arg,
> >>> VIDIOC_TRY_FMT);
> >>>           /* just in case the driver zeroed it again */
> >>>           p->fmt.pix.priv = V4L2_PIX_FMT_PRIV_MAGIC;
> >>>           if (vfd->vfl_type == VFL_TYPE_TOUCH)
> >>>               v4l_pix_format_touch(&p->fmt.pix);
> >>>           return ret;
> >>>       case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
> >>> -        if (unlikely(!ops->vidioc_try_fmt_vid_cap_mplane))
> >>> +        if (unlikely(!ops->vidioc_try_fmt_vid_cap_mplane &&
> >>> +                 !ops->vidioc_try_ext_pix_fmt_vid_cap))
> >>>               break;
> >>>           CLEAR_AFTER_FIELD(p, fmt.pix_mp.xfer_func);
> >>>           for (i = 0; i < p->fmt.pix_mp.num_planes; i++)
> >>>               CLEAR_AFTER_FIELD(&p->fmt.pix_mp.plane_fmt[i],
> >>>                         bytesperline);
> >>> -        return ops->vidioc_try_fmt_vid_cap_mplane(file, fh, arg);
> >>> +        return ops->vidioc_try_fmt_vid_cap_mplane ?
> >>> +               ops->vidioc_try_fmt_vid_cap_mplane(file, fh, arg) :
> >>> +               v4l_fmt_ioctl_via_ext(ops, file, fh, arg,
> >>> +                         VIDIOC_TRY_FMT);
> >>>       case V4L2_BUF_TYPE_VIDEO_OVERLAY:
> >>>           if (unlikely(!ops->vidioc_try_fmt_vid_overlay))
> >>>               break;
> >>> @@ -1799,21 +2236,28 @@ static int v4l_try_fmt(const struct
> >>> v4l2_ioctl_ops *ops,
> >>>           CLEAR_AFTER_FIELD(p, fmt.sliced.io_size);
> >>>           return ops->vidioc_try_fmt_sliced_vbi_cap(file, fh, arg);
> >>>       case V4L2_BUF_TYPE_VIDEO_OUTPUT:
> >>> -        if (unlikely(!ops->vidioc_try_fmt_vid_out))
> >>> +        if (unlikely(!ops->vidioc_try_fmt_vid_out &&
> >>> +                 !ops->vidioc_try_ext_pix_fmt_vid_cap))
> >>>               break;
> >>>           CLEAR_AFTER_FIELD(p, fmt.pix);
> >>> -        ret = ops->vidioc_try_fmt_vid_out(file, fh, arg);
> >>> +        ret = ops->vidioc_try_fmt_vid_out ?
> >>> +              ops->vidioc_try_fmt_vid_out(file, fh, arg) :
> >>> +              v4l_fmt_ioctl_via_ext(ops, file, fh, arg,
> >>> VIDIOC_TRY_FMT);
> >>>           /* just in case the driver zeroed it again */
> >>>           p->fmt.pix.priv = V4L2_PIX_FMT_PRIV_MAGIC;
> >>>           return ret;
> >>>       case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
> >>> -        if (unlikely(!ops->vidioc_try_fmt_vid_out_mplane))
> >>> +        if (unlikely(!ops->vidioc_try_fmt_vid_out_mplane &&
> >>> +                 !ops->vidioc_try_ext_pix_fmt_vid_cap))
> >>>               break;
> >>>           CLEAR_AFTER_FIELD(p, fmt.pix_mp.xfer_func);
> >>>           for (i = 0; i < p->fmt.pix_mp.num_planes; i++)
> >>>               CLEAR_AFTER_FIELD(&p->fmt.pix_mp.plane_fmt[i],
> >>>                         bytesperline);
> >>> -        return ops->vidioc_try_fmt_vid_out_mplane(file, fh, arg);
> >>> +        return ops->vidioc_try_fmt_vid_out_mplane ?
> >>> +               ops->vidioc_try_fmt_vid_out_mplane(file, fh, arg) :
> >>> +               v4l_fmt_ioctl_via_ext(ops, file, fh, arg,
> >>> +                         VIDIOC_TRY_FMT);
> >>>       case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY:
> >>>           if (unlikely(!ops->vidioc_try_fmt_vid_out_overlay))
> >>>               break;
> >>> @@ -1853,6 +2297,45 @@ static int v4l_try_fmt(const struct
> >>> v4l2_ioctl_ops *ops,
> >>>       return -EINVAL;
> >>>   }
> >>> +static int v4l_try_ext_pix_fmt(const struct v4l2_ioctl_ops *ops,
> >>> +                   struct file *file, void *fh, void *arg)
> >>> +{
> >>> +    struct video_device *vfd = video_devdata(file);
> >>> +    struct v4l2_ext_pix_format *ef = arg;
> >>> +    struct v4l2_format f;
> >>> +    int ret = check_fmt(file, ef->type);
> >>> +
> >>> +    if (ret)
> >>> +        return ret;
> >>> +
> >>> +    memset(ef->reserved, 0, sizeof(ef->reserved));
> >>> +
> >>> +    switch (ef->type) {
> >>> +    case V4L2_BUF_TYPE_VIDEO_CAPTURE:
> >>> +        if (ops->vidioc_try_ext_pix_fmt_vid_cap)
> >>> +            return ops->vidioc_try_ext_pix_fmt_vid_cap(file, fh,
> >>> +                                   ef);
> >>> +        break;
> >>> +    case V4L2_BUF_TYPE_VIDEO_OUTPUT:
> >>> +        if (ops->vidioc_try_ext_pix_fmt_vid_out)
> >>> +            return ops->vidioc_try_ext_pix_fmt_vid_out(file, fh,
> >>> +                                   ef);
> >>> +        break;
> >>> +    default:
> >>> +        return -EINVAL;
> >>> +    }
> >>> +
> >>> +    v4l2_ext_pix_format_to_format(ef, &f,
> >>> V4L2_IS_CAP_MULTIPLANAR(vfd));
> >>> +
> >>> +    ret = v4l_try_fmt(ops, file, fh, &f);
> >>> +    if (ret)
> >>> +        /* TODO: retry with M-variant of ef->pixelformat? */
> >>> +        return ret;
> >>> +
> >>> +    v4l2_format_to_ext_pix_format(&f, ef);
> >>> +    return 0;
> >>> +}
> >>> +
> >>>   static int v4l_streamon(const struct v4l2_ioctl_ops *ops,
> >>>                   struct file *file, void *fh, void *arg)
> >>>   {
> >>> @@ -2854,6 +3337,9 @@ static const struct v4l2_ioctl_info
> >>> v4l2_ioctls[] = {
> >>>       IOCTL_INFO(VIDIOC_ENUM_FREQ_BANDS, v4l_enum_freq_bands,
> >>> v4l_print_freq_band, 0),
> >>>       IOCTL_INFO(VIDIOC_DBG_G_CHIP_INFO, v4l_dbg_g_chip_info,
> >>> v4l_print_dbg_chip_info, INFO_FL_CLEAR(v4l2_dbg_chip_info, match)),
> >>>       IOCTL_INFO(VIDIOC_QUERY_EXT_CTRL, v4l_query_ext_ctrl,
> >>> v4l_print_query_ext_ctrl, INFO_FL_CTRL |
> >>> INFO_FL_CLEAR(v4l2_query_ext_ctrl, id)),
> >>> +    IOCTL_INFO(VIDIOC_G_EXT_PIX_FMT, v4l_g_ext_pix_fmt,
> >>> v4l_print_ext_pix_format, 0),
> >>> +    IOCTL_INFO(VIDIOC_S_EXT_PIX_FMT, v4l_s_ext_pix_fmt,
> >>> v4l_print_ext_pix_format, INFO_FL_PRIO),
> >>> +    IOCTL_INFO(VIDIOC_TRY_EXT_PIX_FMT, v4l_try_ext_pix_fmt,
> >>> v4l_print_ext_pix_format, 0),
> >>>   };
> >>>   #define V4L2_IOCTLS ARRAY_SIZE(v4l2_ioctls)
> >>> diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h
> >>> index edb733f21604..c44708dc9355 100644
> >>> --- a/include/media/v4l2-ioctl.h
> >>> +++ b/include/media/v4l2-ioctl.h
> >>> @@ -48,11 +48,17 @@ struct v4l2_fh;
> >>>    * @vidioc_g_fmt_vid_cap: pointer to the function that implements
> >>>    *    :ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for video capture
> >>>    *    in single plane mode
> >>> + * @vidioc_g_ext_pix_fmt_vid_cap: pointer to the function that
> >>> implements
> >>> + *    :ref:`VIDIOC_G_EXT_PIX_FMT <vidioc_g_ext_pix_fmt>` ioctl logic
> >>> for video
> >>> + *    capture
> >>>    * @vidioc_g_fmt_vid_overlay: pointer to the function that implements
> >>>    *    :ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for video overlay
> >>>    * @vidioc_g_fmt_vid_out: pointer to the function that implements
> >>>    *    :ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for video out
> >>>    *    in single plane mode
> >>> + * @vidioc_g_ext_pix_fmt_vid_out: pointer to the function that
> >>> implements
> >>> + *    :ref:`VIDIOC_G_EXT_PIX_FMT <vidioc_g_ext_pix_fmt>` ioctl logic
> >>> for video
> >>> + *    out
> >>>    * @vidioc_g_fmt_vid_out_overlay: pointer to the function that
> >>> implements
> >>>    *    :ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for video
> >>> overlay output
> >>>    * @vidioc_g_fmt_vbi_cap: pointer to the function that implements
> >>> @@ -82,11 +88,16 @@ struct v4l2_fh;
> >>>    * @vidioc_s_fmt_vid_cap: pointer to the function that implements
> >>>    *    :ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for video capture
> >>>    *    in single plane mode
> >>> + * @vidioc_s_ext_pix_fmt_vid_cap: pointer to the function that
> >>> implements
> >>> + *    :ref:`VIDIOC_S_EXT_PIX_FMT <vidioc_g_ext_pix_fmt>` ioctl logic
> >>> for video
> >>> + *    capture
> >>>    * @vidioc_s_fmt_vid_overlay: pointer to the function that implements
> >>>    *    :ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for video overlay
> >>>    * @vidioc_s_fmt_vid_out: pointer to the function that implements
> >>>    *    :ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for video out
> >>>    *    in single plane mode
> >>> + * @vidioc_s_ext_pix_fmt_vid_out: pointer to the function that
> >>> implements
> >>> + *    :ref:`VIDIOC_S_EXT_PIX_FMT <vidioc_g_fmt>` ioctl logic for
> >>> video out
> >>>    * @vidioc_s_fmt_vid_out_overlay: pointer to the function that
> >>> implements
> >>>    *    :ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for video
> >>> overlay output
> >>>    * @vidioc_s_fmt_vbi_cap: pointer to the function that implements
> >>> @@ -116,11 +127,16 @@ struct v4l2_fh;
> >>>    * @vidioc_try_fmt_vid_cap: pointer to the function that implements
> >>>    *    :ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for video
> >>> capture
> >>>    *    in single plane mode
> >>> + * @vidioc_try_ext_pix_fmt_vid_cap: pointer to the function that
> >>> implements
> >>> + *    :ref:`VIDIOC_TRY_EXT_PIX_FMT <vidioc_g_ext_pix_fmt>` ioctl
> >>> logic for
> >>> +    video capture
> >>>    * @vidioc_try_fmt_vid_overlay: pointer to the function that
> >>> implements
> >>>    *    :ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for video
> >>> overlay
> >>>    * @vidioc_try_fmt_vid_out: pointer to the function that implements
> >>>    *    :ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for video out
> >>>    *    in single plane mode
> >>> + * @vidioc_try_ext_pix_fmt_vid_out: pointer to the function that
> >>> implements
> >>> + *    :ref:`VIDIOC_TRY_EXT_PIX_FMT <vidioc_g_fmt>` ioctl logic for
> >>> video out
> >>>    * @vidioc_try_fmt_vid_out_overlay: pointer to the function that
> >>> implements
> >>>    *    :ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for video
> >>> overlay
> >>>    *    output
> >>> @@ -319,10 +335,14 @@ struct v4l2_ioctl_ops {
> >>>       /* VIDIOC_G_FMT handlers */
> >>>       int (*vidioc_g_fmt_vid_cap)(struct file *file, void *fh,
> >>>                       struct v4l2_format *f);
> >>> +    int (*vidioc_g_ext_pix_fmt_vid_cap)(struct file *file, void *fh,
> >>> +                        struct v4l2_ext_pix_format *ef);
> >>>       int (*vidioc_g_fmt_vid_overlay)(struct file *file, void *fh,
> >>>                       struct v4l2_format *f);
> >>>       int (*vidioc_g_fmt_vid_out)(struct file *file, void *fh,
> >>>                       struct v4l2_format *f);
> >>> +    int (*vidioc_g_ext_pix_fmt_vid_out)(struct file *file, void *fh,
> >>> +                        struct v4l2_ext_pix_format *ef);
> >>>       int (*vidioc_g_fmt_vid_out_overlay)(struct file *file, void *fh,
> >>>                           struct v4l2_format *f);
> >>>       int (*vidioc_g_fmt_vbi_cap)(struct file *file, void *fh,
> >>> @@ -349,10 +369,14 @@ struct v4l2_ioctl_ops {
> >>>       /* VIDIOC_S_FMT handlers */
> >>>       int (*vidioc_s_fmt_vid_cap)(struct file *file, void *fh,
> >>>                       struct v4l2_format *f);
> >>> +    int (*vidioc_s_ext_pix_fmt_vid_cap)(struct file *file, void *fh,
> >>> +                        struct v4l2_ext_pix_format *ef);
> >>>       int (*vidioc_s_fmt_vid_overlay)(struct file *file, void *fh,
> >>>                       struct v4l2_format *f);
> >>>       int (*vidioc_s_fmt_vid_out)(struct file *file, void *fh,
> >>>                       struct v4l2_format *f);
> >>> +    int (*vidioc_s_ext_pix_fmt_vid_out)(struct file *file, void *fh,
> >>> +                        struct v4l2_ext_pix_format *ef);
> >>>       int (*vidioc_s_fmt_vid_out_overlay)(struct file *file, void *fh,
> >>>                           struct v4l2_format *f);
> >>>       int (*vidioc_s_fmt_vbi_cap)(struct file *file, void *fh,
> >>> @@ -379,10 +403,14 @@ struct v4l2_ioctl_ops {
> >>>       /* VIDIOC_TRY_FMT handlers */
> >>>       int (*vidioc_try_fmt_vid_cap)(struct file *file, void *fh,
> >>>                         struct v4l2_format *f);
> >>> +    int (*vidioc_try_ext_pix_fmt_vid_cap)(struct file *file, void *fh,
> >>> +                          struct v4l2_ext_pix_format *ef);
> >>>       int (*vidioc_try_fmt_vid_overlay)(struct file *file, void *fh,
> >>>                         struct v4l2_format *f);
> >>>       int (*vidioc_try_fmt_vid_out)(struct file *file, void *fh,
> >>>                         struct v4l2_format *f);
> >>> +    int (*vidioc_try_ext_pix_fmt_vid_out)(struct file *file, void *fh,
> >>> +                          struct v4l2_ext_pix_format *ef);
> >>>       int (*vidioc_try_fmt_vid_out_overlay)(struct file *file, void *fh,
> >>>                            struct v4l2_format *f);
> >>>       int (*vidioc_try_fmt_vbi_cap)(struct file *file, void *fh,
> >>> diff --git a/include/uapi/linux/videodev2.h
> >>> b/include/uapi/linux/videodev2.h
> >>> index d9b7c9177605..a2d850513708 100644
> >>> --- a/include/uapi/linux/videodev2.h
> >>> +++ b/include/uapi/linux/videodev2.h
> >>> @@ -2270,6 +2270,43 @@ struct v4l2_pix_format_mplane {
> >>>       __u8                reserved[7];
> >>>   } __attribute__ ((packed));
> >>> +/**
> >>> + * struct v4l2_ext_pix_format - extended single/multiplanar format
> >>> definition
> >>> + * @type:        type of the data stream;
> >>> V4L2_BUF_TYPE_VIDEO_CAPTURE or
> >>> + *            V4L2_BUF_TYPE_VIDEO_OUTPUT
> >>> + * @width:        image width in pixels
> >>> + * @height:        image height in pixels
> >>> + * @field:        enum v4l2_field; field order (for interlaced video)
> >>> + * @plane_fmt:        per-plane information
> >>> + * @pixelformat:    little endian four character code (fourcc)
> >>> + * @modifier:        modifier applied to the format (used for tiled
> >>> formats
> >>> + *            and other kind of HW-specific formats, like compressed
> >>> + *            formats) as defined in drm_fourcc.h
> >>> + * @colorspace:        enum v4l2_colorspace; supplemental to
> >>> pixelformat
> >>> + * @xfer_func:        enum v4l2_xfer_func, colorspace transfer function
> >>> + * @ycbcr_enc:        enum v4l2_ycbcr_encoding, Y'CbCr encoding
> >>> + * @hsv_enc:        enum v4l2_hsv_encoding, HSV encoding
> >>> + * @quantization:    enum v4l2_quantization, colorspace quantization
> >>> + * @reserved:        extra space reserved for future fields, must be
> >>> set to 0
> >>> + */
> >>> +struct v4l2_ext_pix_format {
> >>> +    __u32 type;
> >>> +    __u32 width;
> >>> +    __u32 height;
> >>> +    __u32 field;
> >>> +    struct v4l2_plane_pix_format plane_fmt[VIDEO_MAX_PLANES];
> >>> +    __u32 pixelformat;
> >>> +    __u64 modifier;
> >>> +    __u32 colorspace;
> >>> +    __u32 xfer_func;
> >>> +    union {
> >>> +        __u32 ycbcr_enc;
> >>> +        __u32 hsv_enc;
> >>> +    };
> >>> +    __u32 quantization;
> >>> +    __u32 reserved[9];
> >>> +};
> >>> +
> >>>   /**
> >>>    * struct v4l2_sdr_format - SDR format definition
> >>>    * @pixelformat:    little endian four character code (fourcc)
> >>> @@ -2583,6 +2620,10 @@ struct v4l2_create_buffers {
> >>>   #define VIDIOC_QUERY_EXT_CTRL    _IOWR('V', 103, struct
> >>> v4l2_query_ext_ctrl)
> >>> +#define VIDIOC_G_EXT_PIX_FMT    _IOWR('V', 104, struct
> >>> v4l2_ext_pix_format)
> >>> +#define VIDIOC_S_EXT_PIX_FMT    _IOWR('V', 105, struct
> >>> v4l2_ext_pix_format)
> >>> +#define VIDIOC_TRY_EXT_PIX_FMT    _IOWR('V', 106, struct
> >>> v4l2_ext_pix_format)
> >>> +
> >>>   /* Reminder: when adding new ioctls please add support for them to
> >>>      drivers/media/v4l2-core/v4l2-compat-ioctl32.c as well! */
> >>>

--
Regards,

Laurent Pinchart