[PATCH v3 0/6] drm: Add colorspace property support to the HDMI helpers

[PATCH v3 0/6] drm: Add colorspace property support to the HDMI helpers

[Jan Claußen]

HDMI connectors set up through drmm_connector_hdmi_init() don't expose
the colorspace property, so userspace can't signal BT.2020 colorimetry
for HDR. KWin, for example, doesn't offer HDR without it.

This series lets drivers declare which colorspaces they support and has
the HDMI helpers create the property and force a modeset when it
changes. dw-hdmi-qp on RK3588 is the first user.

Tested on a Radxa Rock 5B (RK3588) with an LG OLED55B87LC in KDE
Plasma 6.7.5. Only BT.2020 RGB is tested.

Does VOP2 use matching coefficients for BT.709/BT.2020 YCC
output?

Changes in v3:
- Move colorspace handling into the HDMI helpers (Maxime)
- Let drivers declare supported colorspaces instead of exposing all
- Split into a series

Changes in v2:
- Fix possible null pointer dereferencing requested by the Sashiko bot

v2: https://lore.kernel.org/all/20261011142733.7806-1-jan.claussen10@web.de
v1: https://lore.kernel.org/all/20261011132024.2833-1-jan.claussen10@web.de

Jan Claußen (6):
  drm/connector: Fix typo in colorspace error messages
  drm/display: hdmi-state-helper: Force modeset on colorspace change
  drm/connector: hdmi: Create the colorspace property
  drm/bridge-connector: Pass supported colorspaces to the HDMI helpers
  drm/bridge: dw-hdmi-qp: Forward supported colorspaces from platform
    data
  drm/rockchip: dw_hdmi_qp: Advertise BT.709 and BT.2020 colorimetries

 drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c    |  3 +++
 drivers/gpu/drm/display/drm_bridge_connector.c  |  4 ++++
 drivers/gpu/drm/display/drm_hdmi_state_helper.c |  3 ++-
 drivers/gpu/drm/drm_connector.c                 | 17 +++++++++++++----
 drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c  |  4 ++++
 include/drm/bridge/dw_hdmi_qp.h                 |  2 ++
 include/drm/drm_bridge.h                        |  7 +++++++
 include/drm/drm_connector.h                     |  7 +++++++
 8 files changed, 42 insertions(+), 5 deletions(-)

-- 
2.56.0

[PATCH v3 6/6] drm/rockchip: dw_hdmi_qp: Advertise BT.709 and BT.2020 colorimetries

[Jan Claußen]

Expose BT.2020 RGB and YCC colorimetry so userspace can enable HDR
output. Also explicitly expose BT.709 YCC as it is listed in the
Rockchip RK3588 TRM V1.0-Part2 20220309 data sheet.

Tested on a Radxa Rock 5B (RK3588) with an LG OLED55B87LC in KDE
Plasma 6.7.5: enabling HDR switches the colorspace to BT.2020, and
disabling it restores the default.

Signed-off-by: Jan Claußen <jan.claussen10@web.de>
---

Not sure if BT.709 needs to be explicitly exposed here, but it is mentioned in the data sheet.
Might be covered by DRM_MODE_COLORIMETRY_DEFAULT though.

BT.709/BT.2020 YCC are untested.

 drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c | 4 ++++
 1 file changed, 4 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..dbb87dfd000c 100644
--- a/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c
+++ b/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c
@@ -605,6 +605,10 @@ static int dw_hdmi_qp_rockchip_bind(struct device *dev, struct device *master,
 				      BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR444) |
 				      BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR422);
 
+	plat_data.supported_colorspaces = BIT(DRM_MODE_COLORIMETRY_BT709_YCC) |
+				      BIT(DRM_MODE_COLORIMETRY_BT2020_RGB) |
+				      BIT(DRM_MODE_COLORIMETRY_BT2020_YCC);
+
 	encoder = &hdmi->encoder.encoder;
 	encoder->possible_crtcs = drm_of_find_possible_crtcs(drm, dev->of_node);
 
-- 
2.56.0

Re: [PATCH v3 6/6] drm/rockchip: dw_hdmi_qp: Advertise BT.709 and BT.2020 colorimetries

[Chaoyi Chen]

Hi Jan,

On 10/18/2026 8:30 PM, Jan Claußen wrote:
> Expose BT.2020 RGB and YCC colorimetry so userspace can enable HDR
> output. Also explicitly expose BT.709 YCC as it is listed in the
> Rockchip RK3588 TRM V1.0-Part2 20220309 data sheet.
> 
> Tested on a Radxa Rock 5B (RK3588) with an LG OLED55B87LC in KDE
> Plasma 6.7.5: enabling HDR switches the colorspace to BT.2020, and
> disabling it restores the default.
> 
> Signed-off-by: Jan Claußen <jan.claussen10@web.de>
> ---
> 
> Not sure if BT.709 needs to be explicitly exposed here, but it is mentioned in the data sheet.
> Might be covered by DRM_MODE_COLORIMETRY_DEFAULT though.

Cc: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>

Hi Cristian, may be you would be interested in this series?

"DEFAULT" may refer to either BT.601 or BT.709. It should support the
following color spaces:

#define HDMI_COLORSPACE_CAPS_V1		(DRM_MODE_COLORIMETRY_DEFAULT | \
					DRM_MODE_COLORIMETRY_SMPTE_170M_YCC | \
					DRM_MODE_COLORIMETRY_BT709_YCC | \
					DRM_MODE_COLORIMETRY_BT2020_RGB)

#define HDMI_COLORSPACE_CAPS_V2		(HDMI_COLORSPACE_CAPS_V1 | \
					DRM_MODE_COLORIMETRY_DCI_P3_RGB_D65)

> 
> BT.709/BT.2020 YCC are untested.
> 
>  drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c | 4 ++++
>  1 file changed, 4 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..dbb87dfd000c 100644
> --- a/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c
> +++ b/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c
> @@ -605,6 +605,10 @@ static int dw_hdmi_qp_rockchip_bind(struct device *dev, struct device *master,
>  				      BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR444) |
>  				      BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR422);
>  
> +	plat_data.supported_colorspaces = BIT(DRM_MODE_COLORIMETRY_BT709_YCC) |
> +				      BIT(DRM_MODE_COLORIMETRY_BT2020_RGB) |
> +				      BIT(DRM_MODE_COLORIMETRY_BT2020_YCC);
> +
>  	encoder = &hdmi->encoder.encoder;
>  	encoder->possible_crtcs = drm_of_find_possible_crtcs(drm, dev->of_node);
>  

-- 
Best, 
Chaoyi

Re: [PATCH v3 6/6] drm/rockchip: dw_hdmi_qp: Advertise BT.709 and BT.2020 colorimetries

[Cristian Ciocaltea]

On 10/19/26 6:19 AM, Chaoyi Chen wrote:
> Hi Jan,
> 
> On 10/18/2026 8:30 PM, Jan Claußen wrote:
>> Expose BT.2020 RGB and YCC colorimetry so userspace can enable HDR
>> output. Also explicitly expose BT.709 YCC as it is listed in the
>> Rockchip RK3588 TRM V1.0-Part2 20220309 data sheet.
>>
>> Tested on a Radxa Rock 5B (RK3588) with an LG OLED55B87LC in KDE
>> Plasma 6.7.5: enabling HDR switches the colorspace to BT.2020, and
>> disabling it restores the default.
>>
>> Signed-off-by: Jan Claußen <jan.claussen10@web.de>
>> ---
>>
>> Not sure if BT.709 needs to be explicitly exposed here, but it is mentioned in the data sheet.
>> Might be covered by DRM_MODE_COLORIMETRY_DEFAULT though.
> 
> Cc: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
> 
> Hi Cristian, may be you would be interested in this series?

Hi Chaoyi, I already planned to check this out soon. Please note there's a newer
revision of the series, so I think it's best to move further discussions there.

Regards,
Cristian