On Sat, Sep 03, 2022 at 06:35:13AM +0300, Dafna Hirschfeld wrote:
> On 23.08.2022 20:18, Laurent Pinchart wrote:
> > The ISP output color space is configured through the ISP source pad. At
> > the moment, only the quantization can be set. Extend it to the three
> > other color space fields:
> >
> > - The ycbcr_enc field will be used to configure the RGB to YUV matrix
> > (currently hardcoded to Rec. 601).
> >
> > - The colorspace (which controls the color primaries) and xfer_func
> > fields will not be used to configure the ISP, as the corresponding
> > hardware blocks (the cross-talk RGB to RGB matrix and the tone mapping
> > curve) are programmed directly by applications through ISP parameters.
> > Nonetheless, those two fields should be set by applications to match
> > the ISP configuration, in order to propagate the correct color space
> > down the pipeline up to the capture video nodes.
> >
> > Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> > ---
> > Changes since v1:
> >
> > - Fix quantization setting that was set on sink pad by mistake
> > ---
> > .../platform/rockchip/rkisp1/rkisp1-isp.c | 55 ++++++++++++++++---
> > 1 file changed, 48 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> > index d34f32271d74..7869f0cced62 100644
> > --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> > +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> > @@ -609,6 +609,7 @@ static void rkisp1_isp_set_src_fmt(struct rkisp1_isp *isp,
> > struct v4l2_mbus_framefmt *sink_fmt;
> > struct v4l2_mbus_framefmt *src_fmt;
> > const struct v4l2_rect *src_crop;
> > + bool set_csc;
> >
> > sink_fmt = rkisp1_isp_get_pad_fmt(isp, sd_state,
> > RKISP1_ISP_PAD_SINK_VIDEO, which);
> > @@ -645,20 +646,60 @@ static void rkisp1_isp_set_src_fmt(struct rkisp1_isp *isp,
> > src_fmt->height = src_crop->height;
> >
> > /*
> > - * The CSC API is used to allow userspace to force full
> > - * quantization on YUV formats.
> > + * Copy the color space for the sink pad. When converting from Bayer to
> > + * YUV, default to a limited quantization range.
> > */
> > - if (format->flags & V4L2_MBUS_FRAMEFMT_SET_CSC &&
> > - format->quantization == V4L2_QUANTIZATION_FULL_RANGE &&
> > + src_fmt->colorspace = sink_fmt->colorspace;
> > + src_fmt->xfer_func = sink_fmt->xfer_func;
> > + src_fmt->ycbcr_enc = sink_fmt->ycbcr_enc;
> > +
> > + if (sink_info->pixel_enc == V4L2_PIXEL_ENC_BAYER &&
> > src_info->pixel_enc == V4L2_PIXEL_ENC_YUV)
> > - src_fmt->quantization = V4L2_QUANTIZATION_FULL_RANGE;
> > - else if (src_info->pixel_enc == V4L2_PIXEL_ENC_YUV)
> > src_fmt->quantization = V4L2_QUANTIZATION_LIM_RANGE;
> > else
> > - src_fmt->quantization = V4L2_QUANTIZATION_FULL_RANGE;
> > + src_fmt->quantization = sink_fmt->quantization;
> > +
> > + /*
> > + * Allow setting the source color space fields when the SET_CSC flag is
> > + * set and the source format is YUV. If the sink format is YUV, don't
> > + * set the color primaries, transfer function or YCbCr encoding as the
> > + * ISP is bypassed in that case and passes YUV data through without
> > + * modifications.
> > + *
> > + * The color primaries and transfer function are configured through the
> > + * cross-talk matrix and tone curve respectively. Settings for those
> > + * hardware blocks are conveyed through the ISP parameters buffer, as
> > + * they need to combine color space information with other image tuning
> > + * characteristics and can't thus be computed by the kernel based on the
> > + * color space. The source pad colorspace and xfer_func fields are thus
> > + * ignored by the driver, but can be set by userspace to propagate
> > + * accurate color space information down the pipeline.
> > + */
> > + set_csc = !!(format->flags & V4L2_MBUS_FRAMEFMT_SET_CSC);
>
> the (!!) operator is used to convert boolean to interger rigth?
Here it's used to convert an integert to a boolean. The bool type is
stored on one byte, so if the V4L2_MBUS_FRAMEFMT_SET_CSC flag used bit 8
or higher, there would be a risk the result would overflow.
However, given that the bool type is an alias for _Bool, the compiler
will correctly convert any non-zero value to 1. The following code
explains it better:
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
int main(int argc __attribute__((__unused__)),
char *argv[] __attribute__((__unused__)))
{
bool b;
uint8_t u8;
uint8_t u8_notnot;
b = 0x1ff & 0x100;
u8 = 0x1ff & 0x100;
u8_notnot = !!(0x1ff & 0x100);
printf("b = %u, u8 = %u, u8_notnot = %u\n", b, u8, u8_notnot);
return 0;
}
$ gcc -W -Wall -o bool bool.c
bool.c: In function ‘main’:
bool.c:13:14: warning: unsigned conversion from ‘int’ to ‘uint8_t’ {aka ‘unsigned char’} changes value from ‘256’ to ‘0’ [-Woverflow]
13 | u8 = 0x1ff & 0x100;
| ^~~~~
$ ./bool
b = 1, u8 = 0, u8_notnot = 1
I'll drop the !!.
> I think it it not needed here, since 'set_csc' is only used in 'if' conditions
>
> anyway
>
> Reviewed-by: Dafna Hirschfeld <dafna@xxxxxxxxxxxx>
>
> > +
> > + if (set_csc && src_info->pixel_enc == V4L2_PIXEL_ENC_YUV) {
> > + if (sink_info->pixel_enc == V4L2_PIXEL_ENC_BAYER) {
> > + if (format->colorspace != V4L2_COLORSPACE_DEFAULT)
> > + src_fmt->colorspace = format->colorspace;
> > + if (format->xfer_func != V4L2_XFER_FUNC_DEFAULT)
> > + src_fmt->xfer_func = format->xfer_func;
> > + if (format->ycbcr_enc != V4L2_YCBCR_ENC_DEFAULT)
> > + src_fmt->ycbcr_enc = format->ycbcr_enc;
> > + }
> > +
> > + if (format->quantization != V4L2_QUANTIZATION_DEFAULT)
> > + src_fmt->quantization = format->quantization;
> > + }
> >
> > *format = *src_fmt;
> >
> > + /*
> > + * Restore the SET_CSC flag if it was set to indicate support for the
> > + * CSC setting API.
> > + */
> > + if (set_csc)
> > + format->flags |= V4L2_MBUS_FRAMEFMT_SET_CSC;
> > +
> > /* Store the source format info when setting the active format. */
> > if (which == V4L2_SUBDEV_FORMAT_ACTIVE)
> > isp->src_fmt = src_info;
--
Regards,
Laurent Pinchart
