diff mbox series

[v4,09/17] drm/uAPI: Add "active color range" drm property as feedback for userspace

Message ID 20210618091116.14428-10-wse@tuxedocomputers.com (mailing list archive)
State New, archived
Headers show
Series New uAPI drm properties for color management | expand

Commit Message

Werner Sembach June 18, 2021, 9:11 a.m. UTC
Add a new general drm property "active color range" which can be used by
graphic drivers to report the used color range back to userspace.

There was no way to check which color range got actually used on a given
monitor. To surely predict this, one must know the exact capabilities of
the monitor and what the default behaviour of the used driver is. This
property helps eliminating the guessing at this point.

In the future, automatic color calibration for screens might also depend on
this information being available.

Signed-off-by: Werner Sembach <wse@tuxedocomputers.com>
---
 drivers/gpu/drm/drm_connector.c | 59 +++++++++++++++++++++++++++++++++
 include/drm/drm_connector.h     | 27 +++++++++++++++
 2 files changed, 86 insertions(+)

Comments

Pekka Paalanen June 22, 2021, 7 a.m. UTC | #1
On Fri, 18 Jun 2021 11:11:08 +0200
Werner Sembach <wse@tuxedocomputers.com> wrote:

> Add a new general drm property "active color range" which can be used by
> graphic drivers to report the used color range back to userspace.
> 
> There was no way to check which color range got actually used on a given
> monitor. To surely predict this, one must know the exact capabilities of
> the monitor and what the default behaviour of the used driver is. This
> property helps eliminating the guessing at this point.
> 
> In the future, automatic color calibration for screens might also depend on
> this information being available.
> 
> Signed-off-by: Werner Sembach <wse@tuxedocomputers.com>
> ---
>  drivers/gpu/drm/drm_connector.c | 59 +++++++++++++++++++++++++++++++++
>  include/drm/drm_connector.h     | 27 +++++++++++++++
>  2 files changed, 86 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> index 684d7abdf0eb..818de58d972f 100644
> --- a/drivers/gpu/drm/drm_connector.c
> +++ b/drivers/gpu/drm/drm_connector.c
> @@ -897,6 +897,12 @@ static const struct drm_prop_enum_list drm_active_color_format_enum_list[] = {
>  	{ DRM_COLOR_FORMAT_YCRCB420, "ycbcr420" },
>  };
>  
> +static const struct drm_prop_enum_list drm_active_color_range_enum_list[] = {
> +	{ DRM_MODE_COLOR_RANGE_UNSET, "Unknown" },
> +	{ DRM_MODE_COLOR_RANGE_FULL, "Full" },
> +	{ DRM_MODE_COLOR_RANGE_LIMITED_16_235, "Limited 16:235" },

Doesn't "limited" mean different numbers on RGB vs. Y vs. CbCr? I have
a vague recollection that at least one of them was different from the
others.

Documenting DRM_MODE_COLOR_RANGE_UNSET as "unspecified/default" while
the string for it is "Unknown" seems inconsistent to me. I would
recommend to avoid the word "default" because "reset to defaults" might
become a thing one day, and that probably is not the same default as
here.

Is there actually a case for "unknown"? How can it be not known? Or
does it mean "not applicable"?

Otherwise looks good to me.


Thanks,
pq


> +};
> +
>  DRM_ENUM_NAME_FN(drm_get_dp_subconnector_name,
>  		 drm_dp_subconnector_enum_list)
>  
> @@ -1221,6 +1227,14 @@ static const struct drm_prop_enum_list dp_colorspaces[] = {
>   *	drm_connector_attach_active_color_format_property() to install this
>   *	property.
>   *
> + * active color range:
> + *	This read-only property tells userspace the color range actually used by
> + *	the hardware display engine on "the cable" on a connector. The chosen
> + *	value depends on hardware capabilities of the monitor and the used color
> + *	format. Drivers shall use
> + *	drm_connector_attach_active_color_range_property() to install this
> + *	property.
> + *
>   * Connectors also have one standardized atomic property:
>   *
>   * CRTC_ID:
> @@ -2264,6 +2278,51 @@ void drm_connector_set_active_color_format_property(struct drm_connector *connec
>  }
>  EXPORT_SYMBOL(drm_connector_set_active_color_format_property);
>  
> +/**
> + * drm_connector_attach_active_color_range_property - attach "active color range" property
> + * @connector: connector to attach active color range property on.
> + *
> + * This is used to check the applied color range on a connector.
> + *
> + * Returns:
> + * Zero on success, negative errno on failure.
> + */
> +int drm_connector_attach_active_color_range_property(struct drm_connector *connector)
> +{
> +	struct drm_device *dev = connector->dev;
> +	struct drm_property *prop;
> +
> +	if (!connector->active_color_range_property) {
> +		prop = drm_property_create_enum(dev, DRM_MODE_PROP_IMMUTABLE, "active color range",
> +						drm_active_color_range_enum_list,
> +						ARRAY_SIZE(drm_active_color_range_enum_list));
> +		if (!prop)
> +			return -ENOMEM;
> +
> +		connector->active_color_range_property = prop;
> +		drm_object_attach_property(&connector->base, prop, DRM_MODE_COLOR_RANGE_UNSET);
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_connector_attach_active_color_range_property);
> +
> +/**
> + * drm_connector_set_active_color_range_property - sets the active color range property for a
> + * connector
> + * @connector: drm connector
> + * @active_color_range: color range for the connector currently active on "the cable"
> + *
> + * Should be used by atomic drivers to update the active color range over a connector.
> + */
> +void drm_connector_set_active_color_range_property(struct drm_connector *connector,
> +						   enum drm_mode_color_range active_color_range)
> +{
> +	drm_object_property_set_value(&connector->base, connector->active_color_range_property,
> +				      active_color_range);
> +}
> +EXPORT_SYMBOL(drm_connector_set_active_color_range_property);
> +
>  /**
>   * drm_connector_attach_hdr_output_metadata_property - attach "HDR_OUTPUT_METADA" property
>   * @connector: connector to attach the property on.
> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index 8a5197f14e87..9fb7119b7a02 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -648,6 +648,24 @@ struct drm_tv_connector_state {
>  	unsigned int hue;
>  };
>  
> +/**
> + * enum drm_mode_color_range - color_range info for &drm_connector
> + *
> + * This enum is used to represent full or limited color range on the display
> + * connector signal.
> + *
> + * @DRM_MODE_COLOR_RANGE_UNSET:		Color range is unspecified/default.
> + * @DRM_MODE_COLOR_RANGE_FULL:		Color range is full range, 0-255 for
> + *					8-Bit color depth.
> + * DRM_MODE_COLOR_RANGE_LIMITED_16_235:	Color range is limited range, 16-235 for
> + *					8-Bit color depth.
> + */
> +enum drm_mode_color_range {
> +	DRM_MODE_COLOR_RANGE_UNSET,
> +	DRM_MODE_COLOR_RANGE_FULL,
> +	DRM_MODE_COLOR_RANGE_LIMITED_16_235,
> +};
> +
>  /**
>   * struct drm_connector_state - mutable connector state
>   */
> @@ -1392,6 +1410,12 @@ struct drm_connector {
>  	 */
>  	struct drm_property *active_color_format_property;
>  
> +	/**
> +	 * @active_color_range_property: Default connector property for the
> +	 * active color range to be driven out of the connector.
> +	 */
> +	struct drm_property *active_color_range_property;
> +
>  #define DRM_CONNECTOR_POLL_HPD (1 << 0)
>  #define DRM_CONNECTOR_POLL_CONNECT (1 << 1)
>  #define DRM_CONNECTOR_POLL_DISCONNECT (1 << 2)
> @@ -1719,6 +1743,9 @@ void drm_connector_set_active_bpc_property(struct drm_connector *connector, int
>  int drm_connector_attach_active_color_format_property(struct drm_connector *connector);
>  void drm_connector_set_active_color_format_property(struct drm_connector *connector,
>  						    u32 active_color_format);
> +int drm_connector_attach_active_color_range_property(struct drm_connector *connector);
> +void drm_connector_set_active_color_range_property(struct drm_connector *connector,
> +						   enum drm_mode_color_range active_color_range);
>  
>  /**
>   * struct drm_tile_group - Tile group metadata
Werner Sembach June 22, 2021, 9:50 a.m. UTC | #2
Am 22.06.21 um 09:00 schrieb Pekka Paalanen:
> On Fri, 18 Jun 2021 11:11:08 +0200
> Werner Sembach <wse@tuxedocomputers.com> wrote:
>
>> Add a new general drm property "active color range" which can be used by
>> graphic drivers to report the used color range back to userspace.
>>
>> There was no way to check which color range got actually used on a given
>> monitor. To surely predict this, one must know the exact capabilities of
>> the monitor and what the default behaviour of the used driver is. This
>> property helps eliminating the guessing at this point.
>>
>> In the future, automatic color calibration for screens might also depend on
>> this information being available.
>>
>> Signed-off-by: Werner Sembach <wse@tuxedocomputers.com>
>> ---
>>  drivers/gpu/drm/drm_connector.c | 59 +++++++++++++++++++++++++++++++++
>>  include/drm/drm_connector.h     | 27 +++++++++++++++
>>  2 files changed, 86 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
>> index 684d7abdf0eb..818de58d972f 100644
>> --- a/drivers/gpu/drm/drm_connector.c
>> +++ b/drivers/gpu/drm/drm_connector.c
>> @@ -897,6 +897,12 @@ static const struct drm_prop_enum_list drm_active_color_format_enum_list[] = {
>>  	{ DRM_COLOR_FORMAT_YCRCB420, "ycbcr420" },
>>  };
>>  
>> +static const struct drm_prop_enum_list drm_active_color_range_enum_list[] = {
>> +	{ DRM_MODE_COLOR_RANGE_UNSET, "Unknown" },
>> +	{ DRM_MODE_COLOR_RANGE_FULL, "Full" },
>> +	{ DRM_MODE_COLOR_RANGE_LIMITED_16_235, "Limited 16:235" },
> Doesn't "limited" mean different numbers on RGB vs. Y vs. CbCr? I have
> a vague recollection that at least one of them was different from the
> others.

Yes, seems like it does:
https://www.kernel.org/doc/html/v5.12/userspace-api/media/v4l/colorspaces-defs.html#c.V4L.v4l2_quantization

I carried the option names over from "Broadcast RGB", see my other e-mail for more details.

>
> Documenting DRM_MODE_COLOR_RANGE_UNSET as "unspecified/default" while
> the string for it is "Unknown" seems inconsistent to me. I would
> recommend to avoid the word "default" because "reset to defaults" might
> become a thing one day, and that probably is not the same default as
> here.
>
> Is there actually a case for "unknown"? How can it be not known? Or
> does it mean "not applicable"?

Unknown is when no monitor is connected or is when the connector/monitor is disabled.

It also is the initial value when the driver fails to correctly set the property. This shouldn't happen, but I'm
wondering if I should still introduce an _ERROR state instead for this case?

I will rename it, maybe "unset" to match the enum? "not applicable" also fits if either the error state is defined or
not necessary.

>
> Otherwise looks good to me.
>
>
> Thanks,
> pq
>
>
>> +};
>> +
>>  DRM_ENUM_NAME_FN(drm_get_dp_subconnector_name,
>>  		 drm_dp_subconnector_enum_list)
>>  
>> @@ -1221,6 +1227,14 @@ static const struct drm_prop_enum_list dp_colorspaces[] = {
>>   *	drm_connector_attach_active_color_format_property() to install this
>>   *	property.
>>   *
>> + * active color range:
>> + *	This read-only property tells userspace the color range actually used by
>> + *	the hardware display engine on "the cable" on a connector. The chosen
>> + *	value depends on hardware capabilities of the monitor and the used color
>> + *	format. Drivers shall use
>> + *	drm_connector_attach_active_color_range_property() to install this
>> + *	property.
>> + *
>>   * Connectors also have one standardized atomic property:
>>   *
>>   * CRTC_ID:
>> @@ -2264,6 +2278,51 @@ void drm_connector_set_active_color_format_property(struct drm_connector *connec
>>  }
>>  EXPORT_SYMBOL(drm_connector_set_active_color_format_property);
>>  
>> +/**
>> + * drm_connector_attach_active_color_range_property - attach "active color range" property
>> + * @connector: connector to attach active color range property on.
>> + *
>> + * This is used to check the applied color range on a connector.
>> + *
>> + * Returns:
>> + * Zero on success, negative errno on failure.
>> + */
>> +int drm_connector_attach_active_color_range_property(struct drm_connector *connector)
>> +{
>> +	struct drm_device *dev = connector->dev;
>> +	struct drm_property *prop;
>> +
>> +	if (!connector->active_color_range_property) {
>> +		prop = drm_property_create_enum(dev, DRM_MODE_PROP_IMMUTABLE, "active color range",
>> +						drm_active_color_range_enum_list,
>> +						ARRAY_SIZE(drm_active_color_range_enum_list));
>> +		if (!prop)
>> +			return -ENOMEM;
>> +
>> +		connector->active_color_range_property = prop;
>> +		drm_object_attach_property(&connector->base, prop, DRM_MODE_COLOR_RANGE_UNSET);
>> +	}
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL(drm_connector_attach_active_color_range_property);
>> +
>> +/**
>> + * drm_connector_set_active_color_range_property - sets the active color range property for a
>> + * connector
>> + * @connector: drm connector
>> + * @active_color_range: color range for the connector currently active on "the cable"
>> + *
>> + * Should be used by atomic drivers to update the active color range over a connector.
>> + */
>> +void drm_connector_set_active_color_range_property(struct drm_connector *connector,
>> +						   enum drm_mode_color_range active_color_range)
>> +{
>> +	drm_object_property_set_value(&connector->base, connector->active_color_range_property,
>> +				      active_color_range);
>> +}
>> +EXPORT_SYMBOL(drm_connector_set_active_color_range_property);
>> +
>>  /**
>>   * drm_connector_attach_hdr_output_metadata_property - attach "HDR_OUTPUT_METADA" property
>>   * @connector: connector to attach the property on.
>> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
>> index 8a5197f14e87..9fb7119b7a02 100644
>> --- a/include/drm/drm_connector.h
>> +++ b/include/drm/drm_connector.h
>> @@ -648,6 +648,24 @@ struct drm_tv_connector_state {
>>  	unsigned int hue;
>>  };
>>  
>> +/**
>> + * enum drm_mode_color_range - color_range info for &drm_connector
>> + *
>> + * This enum is used to represent full or limited color range on the display
>> + * connector signal.
>> + *
>> + * @DRM_MODE_COLOR_RANGE_UNSET:		Color range is unspecified/default.
>> + * @DRM_MODE_COLOR_RANGE_FULL:		Color range is full range, 0-255 for
>> + *					8-Bit color depth.
>> + * DRM_MODE_COLOR_RANGE_LIMITED_16_235:	Color range is limited range, 16-235 for
>> + *					8-Bit color depth.
>> + */
>> +enum drm_mode_color_range {
>> +	DRM_MODE_COLOR_RANGE_UNSET,
>> +	DRM_MODE_COLOR_RANGE_FULL,
>> +	DRM_MODE_COLOR_RANGE_LIMITED_16_235,
>> +};
>> +
>>  /**
>>   * struct drm_connector_state - mutable connector state
>>   */
>> @@ -1392,6 +1410,12 @@ struct drm_connector {
>>  	 */
>>  	struct drm_property *active_color_format_property;
>>  
>> +	/**
>> +	 * @active_color_range_property: Default connector property for the
>> +	 * active color range to be driven out of the connector.
>> +	 */
>> +	struct drm_property *active_color_range_property;
>> +
>>  #define DRM_CONNECTOR_POLL_HPD (1 << 0)
>>  #define DRM_CONNECTOR_POLL_CONNECT (1 << 1)
>>  #define DRM_CONNECTOR_POLL_DISCONNECT (1 << 2)
>> @@ -1719,6 +1743,9 @@ void drm_connector_set_active_bpc_property(struct drm_connector *connector, int
>>  int drm_connector_attach_active_color_format_property(struct drm_connector *connector);
>>  void drm_connector_set_active_color_format_property(struct drm_connector *connector,
>>  						    u32 active_color_format);
>> +int drm_connector_attach_active_color_range_property(struct drm_connector *connector);
>> +void drm_connector_set_active_color_range_property(struct drm_connector *connector,
>> +						   enum drm_mode_color_range active_color_range);
>>  
>>  /**
>>   * struct drm_tile_group - Tile group metadata
> _______________________________________________
> amd-gfx mailing list
> amd-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
Simon Ser June 22, 2021, 11:48 a.m. UTC | #3
On Tuesday, June 22nd, 2021 at 11:50, Werner Sembach <wse@tuxedocomputers.com> wrote:

> Unknown is when no monitor is connected or is when the
> connector/monitor is disabled.

I think the other connector props (link-status, non-desktop, etc) don't
have a special "unset" value, and instead the value is set to a random
enum entry. User-space should ignore the prop on these disconnected
connectors anyways.
Pekka Paalanen June 23, 2021, 7:32 a.m. UTC | #4
On Tue, 22 Jun 2021 11:48:52 +0000
Simon Ser <contact@emersion.fr> wrote:

> On Tuesday, June 22nd, 2021 at 11:50, Werner Sembach <wse@tuxedocomputers.com> wrote:
> 
> > Unknown is when no monitor is connected or is when the
> > connector/monitor is disabled.  
> 
> I think the other connector props (link-status, non-desktop, etc) don't
> have a special "unset" value, and instead the value is set to a random
> enum entry. User-space should ignore the prop on these disconnected
> connectors anyways.

That sounds fine to me.


Thanks,
pq
Werner Sembach June 23, 2021, 10:17 a.m. UTC | #5
Am 23.06.21 um 09:32 schrieb Pekka Paalanen:
> On Tue, 22 Jun 2021 11:48:52 +0000
> Simon Ser <contact@emersion.fr> wrote:
>
>> On Tuesday, June 22nd, 2021 at 11:50, Werner Sembach <wse@tuxedocomputers.com> wrote:
>>
>>> Unknown is when no monitor is connected or is when the
>>> connector/monitor is disabled.  
>> I think the other connector props (link-status, non-desktop, etc) don't
>> have a special "unset" value, and instead the value is set to a random
>> enum entry. User-space should ignore the prop on these disconnected
>> connectors anyways.
> That sounds fine to me.

Currently the only case for "not applicable" is when the monitor is disconnected, but sicne the properties are so
interdependent, there might be a case in the future where e.g. a color format that has no differentiation between full
and limited arises. When there is no special unset/not applicable option, the userspace has to know exactly when an
option is valid or not, possible requiring additional logic.

Setting a "not applicable" value allows userspace to be more dumb, without much hassle on the kernelspace side.

>
>
> Thanks,
> pq
> _______________________________________________
> amd-gfx mailing list
> amd-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
Pekka Paalanen June 23, 2021, 11:14 a.m. UTC | #6
On Wed, 23 Jun 2021 12:17:40 +0200
Werner Sembach <wse@tuxedocomputers.com> wrote:

> Am 23.06.21 um 09:32 schrieb Pekka Paalanen:
> > On Tue, 22 Jun 2021 11:48:52 +0000
> > Simon Ser <contact@emersion.fr> wrote:
> >  
> >> On Tuesday, June 22nd, 2021 at 11:50, Werner Sembach <wse@tuxedocomputers.com> wrote:
> >>  
> >>> Unknown is when no monitor is connected or is when the
> >>> connector/monitor is disabled.    
> >> I think the other connector props (link-status, non-desktop, etc) don't
> >> have a special "unset" value, and instead the value is set to a random
> >> enum entry. User-space should ignore the prop on these disconnected
> >> connectors anyways.  
> > That sounds fine to me.  
> 
> Currently the only case for "not applicable" is when the monitor is
> disconnected, but sicne the properties are so interdependent, there
> might be a case in the future where e.g. a color format that has no
> differentiation between full and limited arises. When there is no
> special unset/not applicable option, the userspace has to know
> exactly when an option is valid or not, possible requiring additional
> logic.
> 
> Setting a "not applicable" value allows userspace to be more dumb,
> without much hassle on the kernelspace side.

That's a good point too. So "not applicable" would be a value, but
"unknown" would not be.


Thanks,
pq
Werner Sembach June 23, 2021, 11:19 a.m. UTC | #7
Am 23.06.21 um 13:14 schrieb Pekka Paalanen:
> On Wed, 23 Jun 2021 12:17:40 +0200
> Werner Sembach <wse@tuxedocomputers.com> wrote:
>
>> Am 23.06.21 um 09:32 schrieb Pekka Paalanen:
>>> On Tue, 22 Jun 2021 11:48:52 +0000
>>> Simon Ser <contact@emersion.fr> wrote:
>>>  
>>>> On Tuesday, June 22nd, 2021 at 11:50, Werner Sembach <wse@tuxedocomputers.com> wrote:
>>>>  
>>>>> Unknown is when no monitor is connected or is when the
>>>>> connector/monitor is disabled.    
>>>> I think the other connector props (link-status, non-desktop, etc) don't
>>>> have a special "unset" value, and instead the value is set to a random
>>>> enum entry. User-space should ignore the prop on these disconnected
>>>> connectors anyways.  
>>> That sounds fine to me.  
>> Currently the only case for "not applicable" is when the monitor is
>> disconnected, but sicne the properties are so interdependent, there
>> might be a case in the future where e.g. a color format that has no
>> differentiation between full and limited arises. When there is no
>> special unset/not applicable option, the userspace has to know
>> exactly when an option is valid or not, possible requiring additional
>> logic.
>>
>> Setting a "not applicable" value allows userspace to be more dumb,
>> without much hassle on the kernelspace side.
> That's a good point too. So "not applicable" would be a value, but
> "unknown" would not be.
Ok, I have already renamed the "unknown" option to "not applicable" in my next revision (not yet posted to the mailing
list).
>
>
> Thanks,
> pq
diff mbox series

Patch

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 684d7abdf0eb..818de58d972f 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -897,6 +897,12 @@  static const struct drm_prop_enum_list drm_active_color_format_enum_list[] = {
 	{ DRM_COLOR_FORMAT_YCRCB420, "ycbcr420" },
 };
 
+static const struct drm_prop_enum_list drm_active_color_range_enum_list[] = {
+	{ DRM_MODE_COLOR_RANGE_UNSET, "Unknown" },
+	{ DRM_MODE_COLOR_RANGE_FULL, "Full" },
+	{ DRM_MODE_COLOR_RANGE_LIMITED_16_235, "Limited 16:235" },
+};
+
 DRM_ENUM_NAME_FN(drm_get_dp_subconnector_name,
 		 drm_dp_subconnector_enum_list)
 
@@ -1221,6 +1227,14 @@  static const struct drm_prop_enum_list dp_colorspaces[] = {
  *	drm_connector_attach_active_color_format_property() to install this
  *	property.
  *
+ * active color range:
+ *	This read-only property tells userspace the color range actually used by
+ *	the hardware display engine on "the cable" on a connector. The chosen
+ *	value depends on hardware capabilities of the monitor and the used color
+ *	format. Drivers shall use
+ *	drm_connector_attach_active_color_range_property() to install this
+ *	property.
+ *
  * Connectors also have one standardized atomic property:
  *
  * CRTC_ID:
@@ -2264,6 +2278,51 @@  void drm_connector_set_active_color_format_property(struct drm_connector *connec
 }
 EXPORT_SYMBOL(drm_connector_set_active_color_format_property);
 
+/**
+ * drm_connector_attach_active_color_range_property - attach "active color range" property
+ * @connector: connector to attach active color range property on.
+ *
+ * This is used to check the applied color range on a connector.
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int drm_connector_attach_active_color_range_property(struct drm_connector *connector)
+{
+	struct drm_device *dev = connector->dev;
+	struct drm_property *prop;
+
+	if (!connector->active_color_range_property) {
+		prop = drm_property_create_enum(dev, DRM_MODE_PROP_IMMUTABLE, "active color range",
+						drm_active_color_range_enum_list,
+						ARRAY_SIZE(drm_active_color_range_enum_list));
+		if (!prop)
+			return -ENOMEM;
+
+		connector->active_color_range_property = prop;
+		drm_object_attach_property(&connector->base, prop, DRM_MODE_COLOR_RANGE_UNSET);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_connector_attach_active_color_range_property);
+
+/**
+ * drm_connector_set_active_color_range_property - sets the active color range property for a
+ * connector
+ * @connector: drm connector
+ * @active_color_range: color range for the connector currently active on "the cable"
+ *
+ * Should be used by atomic drivers to update the active color range over a connector.
+ */
+void drm_connector_set_active_color_range_property(struct drm_connector *connector,
+						   enum drm_mode_color_range active_color_range)
+{
+	drm_object_property_set_value(&connector->base, connector->active_color_range_property,
+				      active_color_range);
+}
+EXPORT_SYMBOL(drm_connector_set_active_color_range_property);
+
 /**
  * drm_connector_attach_hdr_output_metadata_property - attach "HDR_OUTPUT_METADA" property
  * @connector: connector to attach the property on.
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index 8a5197f14e87..9fb7119b7a02 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -648,6 +648,24 @@  struct drm_tv_connector_state {
 	unsigned int hue;
 };
 
+/**
+ * enum drm_mode_color_range - color_range info for &drm_connector
+ *
+ * This enum is used to represent full or limited color range on the display
+ * connector signal.
+ *
+ * @DRM_MODE_COLOR_RANGE_UNSET:		Color range is unspecified/default.
+ * @DRM_MODE_COLOR_RANGE_FULL:		Color range is full range, 0-255 for
+ *					8-Bit color depth.
+ * DRM_MODE_COLOR_RANGE_LIMITED_16_235:	Color range is limited range, 16-235 for
+ *					8-Bit color depth.
+ */
+enum drm_mode_color_range {
+	DRM_MODE_COLOR_RANGE_UNSET,
+	DRM_MODE_COLOR_RANGE_FULL,
+	DRM_MODE_COLOR_RANGE_LIMITED_16_235,
+};
+
 /**
  * struct drm_connector_state - mutable connector state
  */
@@ -1392,6 +1410,12 @@  struct drm_connector {
 	 */
 	struct drm_property *active_color_format_property;
 
+	/**
+	 * @active_color_range_property: Default connector property for the
+	 * active color range to be driven out of the connector.
+	 */
+	struct drm_property *active_color_range_property;
+
 #define DRM_CONNECTOR_POLL_HPD (1 << 0)
 #define DRM_CONNECTOR_POLL_CONNECT (1 << 1)
 #define DRM_CONNECTOR_POLL_DISCONNECT (1 << 2)
@@ -1719,6 +1743,9 @@  void drm_connector_set_active_bpc_property(struct drm_connector *connector, int
 int drm_connector_attach_active_color_format_property(struct drm_connector *connector);
 void drm_connector_set_active_color_format_property(struct drm_connector *connector,
 						    u32 active_color_format);
+int drm_connector_attach_active_color_range_property(struct drm_connector *connector);
+void drm_connector_set_active_color_range_property(struct drm_connector *connector,
+						   enum drm_mode_color_range active_color_range);
 
 /**
  * struct drm_tile_group - Tile group metadata