Re: [RFC v3 2/2] media: staging: rkisp1: allow quantization conversion from userspace for isp source pad

[Tomasz Figa <tfiga@chromium.org>]

On Fri, Jun 26, 2020 at 2:15 AM Helen Koike <helen.koike@collabora.com> wrote:
>
>
>
> On 6/18/20 4:25 PM, Tomasz Figa wrote:
> > On Thu, Jun 18, 2020 at 08:54:34PM +0200, Dafna Hirschfeld wrote:
> >>
> >>
> >> On 18.06.20 20:49, Tomasz Figa wrote:
> >>> On Thu, Jun 18, 2020 at 08:26:33PM +0200, Dafna Hirschfeld wrote:
> >>>>
> >>>>
> >>>> On 18.06.20 19:27, Tomasz Figa wrote:
> >>>>> On Wed, Jun 10, 2020 at 2:08 PM Tomasz Figa <tfiga@chromium.org> wrote:
> >>>>>>
> >>>>>> On Thu, Jun 4, 2020 at 9:11 PM Dafna Hirschfeld
> >>>>>> <dafna.hirschfeld@collabora.com> wrote:
> >>>>>>>
> >>>>>>> Hi
> >>>>>>>
> >>>>>>> On 04.06.20 19:54, Tomasz Figa wrote:
> >>>>>>>> On Thu, Apr 16, 2020 at 04:56:05PM +0200, Dafna Hirschfeld wrote:
> >>>>>>>>> The isp entity has a hardware support to force full range quantization
> >>>>>>>>> for YUV formats. Use the new API to indicate userspace that
> >>>>>>>>> quantization conversion is supported by adding the flag
> >>>>>>>>> V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION during media code enumeration.
> >>>>>>>>> Then uppon s_fmt on the video source pad, we assign the
> >>>>>>>>> quantization from userspace for YUV formats.
> >>>>>>>>> Also in the capture and resizer entities we retrieve the colorspace
> >>>>>>>>> from the isp entity.
> >>>>>>>>>
> >>>>>>>>> Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
> >>>>>>>>> ---
> >>>>>>>>>     drivers/staging/media/rkisp1/rkisp1-capture.c | 28 ++++++-------
> >>>>>>>>>     drivers/staging/media/rkisp1/rkisp1-common.h  |  2 +
> >>>>>>>>>     drivers/staging/media/rkisp1/rkisp1-isp.c     | 39 +++++++++++++++++--
> >>>>>>>>>     drivers/staging/media/rkisp1/rkisp1-resizer.c | 13 +++++++
> >>>>>>>>>     4 files changed, 65 insertions(+), 17 deletions(-)
> >>>>>>>>>
> >>>>>>>>> diff --git a/drivers/staging/media/rkisp1/rkisp1-capture.c b/drivers/staging/media/rkisp1/rkisp1-capture.c
> >>>>>>>>> index fbf62399fe3d..aca0f93bc772 100644
> >>>>>>>>> --- a/drivers/staging/media/rkisp1/rkisp1-capture.c
> >>>>>>>>> +++ b/drivers/staging/media/rkisp1/rkisp1-capture.c
> >>>>>>>>> @@ -1066,14 +1066,13 @@ static void rkisp1_try_fmt(const struct rkisp1_capture *cap,
> >>>>>>>>>                           const struct v4l2_format_info **fmt_info)
> >>>>>>>>>     {
> >>>>>>>>>        const struct rkisp1_capture_config *config = cap->config;
> >>>>>>>>> -    struct rkisp1_capture *other_cap =
> >>>>>>>>> -                    &cap->rkisp1->capture_devs[cap->id ^ 1];
> >>>>>>>>>        const struct rkisp1_capture_fmt_cfg *fmt;
> >>>>>>>>>        const struct v4l2_format_info *info;
> >>>>>>>>>        const unsigned int max_widths[] = { RKISP1_RSZ_MP_SRC_MAX_WIDTH,
> >>>>>>>>>                                            RKISP1_RSZ_SP_SRC_MAX_WIDTH };
> >>>>>>>>>        const unsigned int max_heights[] = { RKISP1_RSZ_MP_SRC_MAX_HEIGHT,
> >>>>>>>>>                                             RKISP1_RSZ_SP_SRC_MAX_HEIGHT};
> >>>>>>>>> +    struct v4l2_subdev_format isp_sd_fmt;
> >>>>>>>>>
> >>>>>>>>>        fmt = rkisp1_find_fmt_cfg(cap, pixm->pixelformat);
> >>>>>>>>>        if (!fmt) {
> >>>>>>>>> @@ -1081,24 +1080,27 @@ static void rkisp1_try_fmt(const struct rkisp1_capture *cap,
> >>>>>>>>>                pixm->pixelformat = fmt->fourcc;
> >>>>>>>>>        }
> >>>>>>>>>
> >>>>>>>>> +    rkisp1_get_isp_src_fmt(cap->rkisp1, &isp_sd_fmt);
> >>>>>>>>> +    pixm->field = isp_sd_fmt.format.field;
> >>>>>>>>> +    pixm->colorspace = isp_sd_fmt.format.colorspace;
> >>>>>>>>> +    pixm->ycbcr_enc = isp_sd_fmt.format.ycbcr_enc;
> >>>>>>>>> +    pixm->xfer_func = isp_sd_fmt.format.xfer_func;
> >>>>>>>>> +
> >>>>>>>>> +    /*
> >>>>>>>>> +     * isp has a feature to set full range quantization for yuv formats.
> >>>>>>>>
> >>>>>>>> How about "select between limited and full range for YUV formats"?
> >>>>>>>>
> >>>>>>>>> +     * so we need to get the format from the isp.
> >>>>>>>>> +     */
> >>>>>>>>> +    pixm->quantization = isp_sd_fmt.format.quantization;
> >>>>>>>>> +    if (!v4l2_is_format_yuv(cap->pix.info))
> >>>>>>>>> +            pixm->quantization = V4L2_QUANTIZATION_FULL_RANGE;
> >>>>>>>>> +
> >>>>>>>>>        pixm->width = clamp_t(u32, pixm->width,
> >>>>>>>>>                              RKISP1_RSZ_SRC_MIN_WIDTH, max_widths[cap->id]);
> >>>>>>>>>        pixm->height = clamp_t(u32, pixm->height,
> >>>>>>>>>                               RKISP1_RSZ_SRC_MIN_HEIGHT, max_heights[cap->id]);
> >>>>>>>>>
> >>>>>>>>> -    pixm->field = V4L2_FIELD_NONE;
> >>>>>>>>> -    pixm->colorspace = V4L2_COLORSPACE_DEFAULT;
> >>>>>>>>> -    pixm->ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT;
> >>>>>>>>> -
> >>>>>>>>>        info = rkisp1_fill_pixfmt(pixm, cap->id);
> >>>>>>>>>
> >>>>>>>>> -    /* can not change quantization when stream-on */
> >>>>>>>>> -    if (other_cap->is_streaming)
> >>>>>>>>> -            pixm->quantization = other_cap->pix.fmt.quantization;
> >>>>>>>>> -    /* output full range by default, take effect in params */
> >>>>>>>>> -    else if (!pixm->quantization ||
> >>>>>>>>> -             pixm->quantization > V4L2_QUANTIZATION_LIM_RANGE)
> >>>>>>>>> -            pixm->quantization = V4L2_QUANTIZATION_FULL_RANGE;
> >>>>>>>>>
> >>>>>>>>>        if (fmt_cfg)
> >>>>>>>>>                *fmt_cfg = fmt;
> >>>>>>>>> diff --git a/drivers/staging/media/rkisp1/rkisp1-common.h b/drivers/staging/media/rkisp1/rkisp1-common.h
> >>>>>>>>> index 2d7b7e078636..7a5576fa14c9 100644
> >>>>>>>>> --- a/drivers/staging/media/rkisp1/rkisp1-common.h
> >>>>>>>>> +++ b/drivers/staging/media/rkisp1/rkisp1-common.h
> >>>>>>>>> @@ -300,6 +300,8 @@ int rkisp1_isp_register(struct rkisp1_device *rkisp1,
> >>>>>>>>>                        struct v4l2_device *v4l2_dev);
> >>>>>>>>>     void rkisp1_isp_unregister(struct rkisp1_device *rkisp1);
> >>>>>>>>>
> >>>>>>>>> +int rkisp1_get_isp_src_fmt(struct rkisp1_device *rkisp1,
> >>>>>>>>> +                       struct v4l2_subdev_format *sd_fmt);
> >>>>>>>>>     const struct rkisp1_isp_mbus_info *rkisp1_isp_mbus_info_get(u32 mbus_code);
> >>>>>>>>>
> >>>>>>>>>     irqreturn_t rkisp1_isp_isr(struct rkisp1_device *rkisp1);
> >>>>>>>>> diff --git a/drivers/staging/media/rkisp1/rkisp1-isp.c b/drivers/staging/media/rkisp1/rkisp1-isp.c
> >>>>>>>>> index dee8e96f3900..6fdf5ed0b6b1 100644
> >>>>>>>>> --- a/drivers/staging/media/rkisp1/rkisp1-isp.c
> >>>>>>>>> +++ b/drivers/staging/media/rkisp1/rkisp1-isp.c
> >>>>>>>>> @@ -613,6 +613,10 @@ static int rkisp1_isp_enum_mbus_code(struct v4l2_subdev *sd,
> >>>>>>>>>
> >>>>>>>>>                if (code->index == pos - 1) {
> >>>>>>>>>                        code->code = fmt->mbus_code;
> >>>>>>>>> +                    if (fmt->pixel_enc == V4L2_PIXEL_ENC_YUV &&
> >>>>>>>>> +                        dir == RKISP1_DIR_SRC)
> >>>>>>>>> +                            code->flags =
> >>>>>>>>> +                                    V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION;
> >>>>>>>>>                        return 0;
> >>>>>>>>>                }
> >>>>>>>>>        }
> >>>>>>>>> @@ -639,12 +643,21 @@ static int rkisp1_isp_init_config(struct v4l2_subdev *sd,
> >>>>>>>>>        sink_crop->height = RKISP1_DEFAULT_HEIGHT;
> >>>>>>>>>        sink_crop->left = 0;
> >>>>>>>>>        sink_crop->top = 0;
> >>>>>>>>> +    sink_fmt->colorspace = V4L2_COLORSPACE_SRGB;
> >>>>>>>>> +    sink_fmt->ycbcr_enc = V4L2_MAP_YCBCR_ENC_DEFAULT(sink_fmt->colorspace);
> >>>>>>>>> +    sink_fmt->xfer_func = V4L2_MAP_XFER_FUNC_DEFAULT(sink_fmt->colorspace);
> >>>>>>>>> +    sink_fmt->quantization = V4L2_QUANTIZATION_FULL_RANGE;
> >>>>>>>>> +
> >>>>>>>>>
> >>>>>>>>>        src_fmt = v4l2_subdev_get_try_format(sd, cfg,
> >>>>>>>>>                                             RKISP1_ISP_PAD_SOURCE_VIDEO);
> >>>>>>>>>        *src_fmt = *sink_fmt;
> >>>>>>>>>        src_fmt->code = RKISP1_DEF_SRC_PAD_FMT;
> >>>>>>>>> -    src_fmt->quantization = V4L2_QUANTIZATION_FULL_RANGE;
> >>>>>>>>> +    src_fmt->colorspace = V4L2_COLORSPACE_SRGB;
> >>>>>>>>> +    src_fmt->ycbcr_enc = V4L2_MAP_YCBCR_ENC_DEFAULT(src_fmt->colorspace);
> >>>>>>>>> +    src_fmt->xfer_func = V4L2_MAP_XFER_FUNC_DEFAULT(src_fmt->colorspace);
> >>>>>>>>> +    src_fmt->quantization = V4L2_QUANTIZATION_LIM_RANGE;
> >>>>>>>>> +
> >>>>>>>>>
> >>>>>>>>>        src_crop = v4l2_subdev_get_try_crop(sd, cfg,
> >>>>>>>>>                                            RKISP1_ISP_PAD_SOURCE_VIDEO);
> >>>>>>>>> @@ -687,10 +700,17 @@ static void rkisp1_isp_set_src_fmt(struct rkisp1_isp *isp,
> >>>>>>>>>                isp->src_fmt = mbus_info;
> >>>>>>>>>        src_fmt->width  = src_crop->width;
> >>>>>>>>>        src_fmt->height = src_crop->height;
> >>>>>>>>> -    src_fmt->quantization = format->quantization;
> >>>>>>>>> -    /* full range by default */
> >>>>>>>>> -    if (!src_fmt->quantization)
> >>>>>>>>> +
> >>>>>>>>> +    src_fmt->colorspace = V4L2_COLORSPACE_SRGB;
> >>>>>>>>> +    src_fmt->ycbcr_enc = V4L2_MAP_YCBCR_ENC_DEFAULT(src_fmt->colorspace);
> >>>>>>>>> +    src_fmt->xfer_func = V4L2_MAP_XFER_FUNC_DEFAULT(src_fmt->colorspace);
> >>>>>>>>> +
> >>>>>>>>> +    if (mbus_info->pixel_enc == V4L2_PIXEL_ENC_BAYER)
> >>>>>>>>>                src_fmt->quantization = V4L2_QUANTIZATION_FULL_RANGE;
> >>>>>>>>> +    else if (format->quantization == V4L2_QUANTIZATION_DEFAULT)
> >>>>>>>>> +            src_fmt->quantization = V4L2_QUANTIZATION_LIM_RANGE;
> >>>>>>>>> +    else
> >>>>>>>>> +            src_fmt->quantization = format->quantization;
> >>>>>>>>>
> >>>>>>>>>        *format = *src_fmt;
> >>>>>>>>>     }
> >>>>>>>>> @@ -1068,6 +1088,17 @@ int rkisp1_isp_register(struct rkisp1_device *rkisp1,
> >>>>>>>>>        return ret;
> >>>>>>>>>     }
> >>>>>>>>>
> >>>>>>>>> +int rkisp1_get_isp_src_fmt(struct rkisp1_device *rkisp1,
> >>>>>>>>> +                       struct v4l2_subdev_format *sd_fmt)
> >>>>>>>>> +{
> >>>>>>>>> +    struct rkisp1_isp *isp = &rkisp1->isp;
> >>>>>>>>> +
> >>>>>>>>> +    sd_fmt->which = V4L2_SUBDEV_FORMAT_ACTIVE;
> >>>>>>>>> +    sd_fmt->pad = RKISP1_ISP_PAD_SOURCE_VIDEO;
> >>>>>>>>> +
> >>>>>>>>> +    return v4l2_subdev_call(&isp->sd, pad, get_fmt, NULL, sd_fmt);
> >>>>>>>>
> >>>>>>>> Do we need to get through the external API to access data that is
> >>>>>>>> driver-internal anyway?
> >>>>>>>>
> >>>>>>>>> +}
> >>>>>>>>> +
> >>>>>>>>>     void rkisp1_isp_unregister(struct rkisp1_device *rkisp1)
> >>>>>>>>>     {
> >>>>>>>>>        struct v4l2_subdev *sd = &rkisp1->isp.sd;
> >>>>>>>>> diff --git a/drivers/staging/media/rkisp1/rkisp1-resizer.c b/drivers/staging/media/rkisp1/rkisp1-resizer.c
> >>>>>>>>> index 7b6b7ddd4169..8705b133de68 100644
> >>>>>>>>> --- a/drivers/staging/media/rkisp1/rkisp1-resizer.c
> >>>>>>>>> +++ b/drivers/staging/media/rkisp1/rkisp1-resizer.c
> >>>>>>>>> @@ -525,6 +525,7 @@ static void rkisp1_rsz_set_sink_fmt(struct rkisp1_resizer *rsz,
> >>>>>>>>>        const struct rkisp1_isp_mbus_info *mbus_info;
> >>>>>>>>>        struct v4l2_mbus_framefmt *sink_fmt, *src_fmt;
> >>>>>>>>>        struct v4l2_rect *sink_crop;
> >>>>>>>>> +    struct v4l2_subdev_format isp_sd_fmt;
> >>>>>>>>>
> >>>>>>>>>        sink_fmt = rkisp1_rsz_get_pad_fmt(rsz, cfg, RKISP1_RSZ_PAD_SINK, which);
> >>>>>>>>>        src_fmt = rkisp1_rsz_get_pad_fmt(rsz, cfg, RKISP1_RSZ_PAD_SRC, which);
> >>>>>>>>> @@ -539,8 +540,20 @@ static void rkisp1_rsz_set_sink_fmt(struct rkisp1_resizer *rsz,
> >>>>>>>>>        if (which == V4L2_SUBDEV_FORMAT_ACTIVE)
> >>>>>>>>>                rsz->pixel_enc = mbus_info->pixel_enc;
> >>>>>>>>>
> >>>>>>>>> +    rkisp1_get_isp_src_fmt(rsz->rkisp1, &isp_sd_fmt);
> >>>>>>>>> +
> >>>>>>>>
> >>>>>>>> Is this necessary? My understanding was that in the subdev model, it was
> >>>>>>>> the userspace responsibility to propagate any configuration changes through
> >>>>>>>> the graph.
> >>>>>>>>
> >>>>>>>> Also, doing this only here wouldn't fully maintain the
> >>>>>>>> consistency of the state. For example, if one sets the ISP subdev format
> >>>>>>>> first, then the resizer subdev and then the ISP subdev again, wouldn't the
> >>>>>>>> resizer subdev end up with a wrong format?
> >>>>>>>
> >>>>>>> yes, this is indeed a bug, I am preparing v4 now.
> >>>>>>> What I thought to do is adding quantization conversion
> >>>>>>> support also on ther resizer and capture entities.
> >>>>>>> Then in the 'link_validation' callbacks, there
> >>>>>>> is a validation that the quantization fields matches.
> >>>>>>
> >>>>>> My understanding is that, if we have the following topology
> >>>>>>
> >>>>>> [ ISP ] -> [ Resizer ] -> [ Video node ]
> >>>>>>
> >>>>>> then the ISP source pad would have the csc capability, while resizer
> >>>>>> and video node would just accept whatever is configured on their sink
> >>>>>> pads (no need for csc capability for that) and propagate that to their
> >>>>>> outputs, i.e. resizer source pad and video node CAPTURE format.
> >>>>>>
> >>>>>> Is this what you were going to implement?
> >>>> Hi, I sent a v4 where the CSC capability is set on the reiszer and capture as well.
> >>>> I can send a v5 implementing it the way you suggest. Currently the doc says that the colorspace fields
> >>>> must be set by the driver for capture streams. This implies that userspace can set it
> >>>> only if the CSC is supported.
> >>>
> >>> Why would the userspace have to set it for the capture stream on the
> >>> resizer and video nodes? Couldn't the userspace set it to DEFAULT and
> >>> then the driver override to whatever it received on the corresponding
> >>> sink?
>
> According to the documentation [1]:
>
> "the default quantization encoding as defined by the colorspace"
>
> Then, for instance, the default for V4L2_COLORSPACE_SRGB is limited range [2].
>
> Unless we change the definition of DEFAULT to let it accept whatever it receives on the corresponding sink.
>
> Then the way I understand is:
>
> [sensor]->[isp]->[resizer]->[capture]
>
> Userspace should set quantization on:
> * sensor source pad
> * isp sink pad
> * resizer sink pad
> * capture node
>
> The remaining source pads would get values propagated from their sink pads.
>
> [1] https://linuxtv.org/downloads/v4l-dvb-apis-new/userspace-api/v4l/colorspaces-defs.html#c.v4l2_quantization
> [2] https://linuxtv.org/downloads/v4l-dvb-apis-new/userspace-api/v4l/colorspaces-details.html#col-srgb

After discussing this offline, we concluded that:
- only the source pad of the ISP entity should expose the CSC capability,
- the CAPTURE video node should expose only the formats/color spaces
compatible with the current setting of the resizer source,
- consistency between the resizer source format and CAPTURE format
should be implicitly maintained by the driver.

Below is the rationale for that:
- In the MC model, the video node represents the DMA alone (and thus
the reason to have the resizer entities at all) and since the
colorspace is not a property of the DMA, it doesn't belong there.
- Even if we put that aside, both MP and SP can only output the same
colorspace, which would create a dependency between the configuration
of the two video nodes, which is not something well defined by V4L2.
- A video interface in the MC API doesn't expose control over its
input format, which means that the relation between the other side of
the link (resizer source) and the video node is implicit and needs to
be handled internally in the driver.
- V4L2, as opposed to MC, requires that the current state is always
consistent and valid. In this case it means that an ioctl on the video
node must not be able to alter the state in a way that would make it
inconsistent with the state of the matching resizer source.

Best regards,
Tomasz