Hi,
On 7/22/20 10:12 AM, Tomasz Figa wrote:
> On Fri, Jul 03, 2020 at 05:00:40PM -0300, Helen Koike wrote:
>> Hi Dafna,
>>
>> Thanks for your patch.
>>
>> On 7/3/20 2:10 PM, Dafna Hirschfeld wrote:
>>> The isp entity has a hardware support to force full range quantization
>>> for YUV formats. Use the subdev CSC API to allow userspace to set the
>>> quantization for YUV formats on the isp entity.
>>>
>>> - The flag V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION is set on
>>> YUV formats during enumeration of the isp formats on the source pad.
>>> - The full quantization is set on YUV formats if userspace ask it
>>> on the isp entity using the flag V4L2_MBUS_FRAMEFMT_SET_CSC.
>>>
>>> On the capture and the resizer, the quantization is read-only
>>> and always set to the default quantization.
>>>
>>> Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@xxxxxxxxxxxxx>
>>> ---
>>> drivers/staging/media/rkisp1/TODO | 2 +-
>>> drivers/staging/media/rkisp1/rkisp1-capture.c | 10 ----------
>>> drivers/staging/media/rkisp1/rkisp1-isp.c | 18 ++++++++++++++----
>>> 3 files changed, 15 insertions(+), 15 deletions(-)
>>>
>>> diff --git a/drivers/staging/media/rkisp1/TODO b/drivers/staging/media/rkisp1/TODO
>>> index c0cbec0a164d..db05288949bd 100644
>>> --- a/drivers/staging/media/rkisp1/TODO
>>> +++ b/drivers/staging/media/rkisp1/TODO
>>> @@ -2,7 +2,7 @@
>>> * Use threaded interrupt for rkisp1_stats_isr(), remove work queue.
>>> * Fix checkpatch errors.
>>> * Review and comment every lock
>>> -* Handle quantization
>>> +* Add uapi docs. Remeber to add documentation of how quantization is handled.
>>> * Document rkisp1-common.h
>>> * streaming paths (mainpath and selfpath) check if the other path is streaming
>>> in several places of the code, review this, specially that it doesn't seem it
>>> diff --git a/drivers/staging/media/rkisp1/rkisp1-capture.c b/drivers/staging/media/rkisp1/rkisp1-capture.c
>>> index f69235f82c45..93d6846886f2 100644
>>> --- a/drivers/staging/media/rkisp1/rkisp1-capture.c
>>> +++ b/drivers/staging/media/rkisp1/rkisp1-capture.c
>>> @@ -1085,8 +1085,6 @@ 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,
>>> @@ -1111,14 +1109,6 @@ static void rkisp1_try_fmt(const struct rkisp1_capture *cap,
>>>
>>> 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;
>>> if (fmt_info)
>>> diff --git a/drivers/staging/media/rkisp1/rkisp1-isp.c b/drivers/staging/media/rkisp1/rkisp1-isp.c
>>> index 58c90c67594d..d575c1e4dc4b 100644
>>> --- a/drivers/staging/media/rkisp1/rkisp1-isp.c
>>> +++ b/drivers/staging/media/rkisp1/rkisp1-isp.c
>>> @@ -589,6 +589,10 @@ 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_ISP_SD_SRC)
>>> + code->flags =
>>> + V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION;
>>> return 0;
>>> }
>>> }
>>> @@ -620,7 +624,6 @@ static int rkisp1_isp_init_config(struct v4l2_subdev *sd,
>>> 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_crop = v4l2_subdev_get_try_crop(sd, cfg,
>>> RKISP1_ISP_PAD_SOURCE_VIDEO);
>>> @@ -663,10 +666,17 @@ 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)
>>> +
>>> + /*
>>> + * The CSC API is used to allow userspace to force full
>>> + * quantization on YUV formats.
>>> + */
>>> + if (format->flags & V4L2_MBUS_FRAMEFMT_SET_CSC &&
>>> + format->quantization == V4L2_QUANTIZATION_FULL_RANGE &&
>>> + mbus_info->pixel_enc == V4L2_PIXEL_ENC_YUV)
>>> src_fmt->quantization = V4L2_QUANTIZATION_FULL_RANGE;
>>> + else
>>> + src_fmt->quantization = V4L2_QUANTIZATION_DEFAULT;
>>
>> According to the docs [1]:
>>
>> [1] https://linuxtv.org/downloads/v4l-dvb-apis-new/userspace-api/v4l/colorspaces-defs.html?highlight=quantization
>>
>> "The default colorspace. This can be used by applications to let the driver fill in the colorspace."
>>
>> So, in my understanding, the driver should never return V4L2_QUANTIZATION_DEFAULT to userspace.
>>
>
> The part of the documentation you quoted comes from the description of
> V4L2_COLORSPACE_DEFAULT and not V4L2_QUANTIZATION_DEFAULT.
>
> For the latter it says:
>
> "Use the default quantization encoding as defined by the colorspace.
> This is always full range for R’G’B’ (except for the BT.2020 colorspace)
> and HSV. It is usually limited range for Y’CbCr."
>
> Which, in my understanding, doesn't suggest in any way that it shouldn't
> be returned by the driver. There is also a valid case when the driver
> simply doesn't know or care what quantization the captured signal uses.
Thanks for this clarification.
>
> However, in this case, I don't see why we would return DEFAULT here
> indeed, as the driver has the full knowledge, RGB is full range and YUV
> is limited range unless full range was requested.
>
>> We have the same issue in the resizer.
>>
>> I also see an issue in the capture that allows userspace to change quantization, and this should be fixed.
>>
>> In my understanding, since you are leaving all the other pads and video nodes with read-only quantization,
>> changing quantization in the ISP source pad should change the readings in all the other pads and video nodes.
>> So, if all pads are reporting V4L2_QUANTIZATION_LIM_RANGE (which is the default for sRGB colorspace), and userspace sets
>> V4L2_QUANTIZATION_FULL_RANGE to the isp source pad, then all the other pads and video nodes should also report
>> V4L2_QUANTIZATION_FULL_RANGE, since this will be the actual quantization used by the driver.
>
> This was extensively discussed at v3:
> https://patchwork.kernel.org/patch/11493105/
>
> The conclusion is that there is no value from both the kernel and the userspace point of
> view in propagating this to the end of the pipeline, because the
> hardware components later in the pipeline don't care and the userspace,
> given the DEFAULT quantization value, can infer the exact quantziation from the
> pipeline - here from what it configured at the ISP entity.
Let's use DEFAULT then, sounds the simplest solution imho, unless you disagree.
Acked-by: Helen Koike <helen.koike@xxxxxxxxxxxxx>
Regards,
Helen
>
> Best regards,
> Tomasz
>
