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

[Jan Claußen]

Hi Cristian and Chaoyi,

thank you and noted. Going to look into this soon!

Any other concerns about my approach? Main concern sounds like it’s not the only one.

Cheers,
Jan


> Am 11.11.2026 um 10:41 schrieb Cristian Ciocaltea <cristian.ciocaltea@xxxxxxxxxxxxx>:
> 
> 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@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.
> 
> Thanks for the heads-up; I haven't checked the recent vendor kernel changes.
> 
> Regards,
> Cristian
>