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

[Cristian Ciocaltea <cristian.ciocaltea@collabora.com>]

Hi Chaoyi,

On 11/11/26 8:19 AM, Chaoyi Chen wrote:
> 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@web.de>
>>> ---
>>>  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.

Thanks for the heads-up; I haven't checked the recent vendor kernel changes.

Regards,
Cristian