Re: [PATCH v4 6/7] drm/rockchip: dw_hdmi_qp: Set the VOP2 color space from the connector

[Chaoyi Chen]

Hi Cristian and Jan,

On 11/11/2026 3:05 AM, Cristian Ciocaltea wrote:
> Hi Jan,
> 
> On 10/18/26 5:31 PM, Jan Claußen wrote:
>> VOP2 converts RGB to YCbCr using the matrix selected by the CRTC
>> state's color_space, but the HDMI encoder never sets it, so VOP2
>> always converts with BT.709. Once the colorspace property can
>> signal BT.2020 colorimetry to the sink, a YCbCr output would be
>> encoded with BT.709 and decoded with BT.2020.
>>
>> Derive color_space from the connector colorspace before the early
>> return, so that a colorspace change alone is applied.
>>
>> Signed-off-by: Jan Claußen <jan.claussen10@xxxxxx>
>> ---
>>  drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c | 16 ++++++++++++++++
>>  1 file changed, 16 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c b/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c
>> index 9c4cf68d79d5..10c5b6d6406e 100644
>> --- a/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c
>> +++ b/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c
>> @@ -17,6 +17,7 @@
>>  #include <linux/phy/phy.h>
>>  #include <linux/phy/phy-hdmi.h>
>>  #include <linux/regmap.h>
>> +#include <linux/videodev2.h>
>>  #include <linux/workqueue.h>
>>  
>>  #include <drm/bridge/dw_hdmi_qp.h>
>> @@ -187,6 +188,19 @@ static int dw_hdmi_qp_rockchip_get_vop_format(struct drm_encoder *encoder,
>>  	return bstate->output_bus_cfg.format;
>>  }
>>  
>> +static u32
>> +dw_hdmi_qp_rockchip_color_space(const struct drm_connector_state *conn_state)
>> +{
>> +	switch (conn_state->colorspace) {
>> +	case DRM_MODE_COLORIMETRY_BT2020_RGB:
>> +	case DRM_MODE_COLORIMETRY_BT2020_YCC:
>> +	case DRM_MODE_COLORIMETRY_BT2020_CYCC:
>> +		return V4L2_COLORSPACE_BT2020;
>> +	default:
>> +		return V4L2_COLORSPACE_DEFAULT;
>> +	}
>> +}
> 
> My main concern is introducing V4L2_COLORSPACE_* logic into a DRM bridge driver,
> which should rather rely on enum drm_colorspace / DRM_MODE_COLORIMETRY_*.
> Translating the DRM colorimetry into V4L2 values only for VOP2 to map them back
> to a CSC matrix doesn't seem fully justified.
> 
> The root problem is rather on the VOP2 side: the color_space field in struct
> rockchip_crtc_state and its V4L2-based handling in the CSC selection look like
> leftovers inherited from the vendor kernel, and I think this is a good time to
> clean that up instead of building on it.
> 

Yep. And if you look at the latest vendor kernel code, we have also
removed the V4L2_COLORSPACE_* related content and switched to DRM.

-- 
Best, 
Chaoyi