diff mbox series

[v3,3/9] drm/vc4: hdmi: Add Broadcast RGB property to allow override of RGB range

Message ID 20221207-rpi-hdmi-improvements-v3-3-bdd54f66884e@cerno.tech (mailing list archive)
State New, archived
Headers show
Series drm/vc4: hdmi: Broadcast RGB, BT601, BT2020 | expand

Commit Message

Maxime Ripard March 6, 2023, 10:46 a.m. UTC
From: Dave Stevenson <dave.stevenson@raspberrypi.com>

Copy Intel's "Broadcast RGB" property semantics to add manual override
of the HDMI pixel range for monitors that don't abide by the content
of the AVI Infoframe.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 drivers/gpu/drm/vc4/vc4_hdmi.c | 97 ++++++++++++++++++++++++++++++++++++++++--
 drivers/gpu/drm/vc4/vc4_hdmi.h |  9 ++++
 2 files changed, 102 insertions(+), 4 deletions(-)

Comments

Daniel Vetter Oct. 11, 2023, 1:23 p.m. UTC | #1
On Mon, 6 Mar 2023 at 11:49, Maxime Ripard <maxime@cerno.tech> wrote:
>
> From: Dave Stevenson <dave.stevenson@raspberrypi.com>
>
> Copy Intel's "Broadcast RGB" property semantics to add manual override
> of the HDMI pixel range for monitors that don't abide by the content
> of the AVI Infoframe.
>
> Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
> Signed-off-by: Maxime Ripard <maxime@cerno.tech>

Stumbled over this grepping around, but would have been nice to lift
this into drm code and document the property. It's one of the legacy
ones from the table of horrors after all ...

Shouldn't be an uapi problem because it's copypasted to much, just not great.
-Sima
> ---
>  drivers/gpu/drm/vc4/vc4_hdmi.c | 97 ++++++++++++++++++++++++++++++++++++++++--
>  drivers/gpu/drm/vc4/vc4_hdmi.h |  9 ++++
>  2 files changed, 102 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> index 522cfbc83fe4..d23c0c3df2ee 100644
> --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> @@ -154,10 +154,16 @@ static bool vc4_hdmi_mode_needs_scrambling(const struct drm_display_mode *mode,
>  }
>
>  static bool vc4_hdmi_is_full_range_rgb(struct vc4_hdmi *vc4_hdmi,
> -                                      const struct drm_display_mode *mode)
> +                                      struct vc4_hdmi_connector_state *vc4_state)
>  {
> +       const struct drm_display_mode *mode = &vc4_hdmi->saved_adjusted_mode;
>         struct drm_display_info *display = &vc4_hdmi->connector.display_info;
>
> +       if (vc4_state->broadcast_rgb == VC4_HDMI_BROADCAST_RGB_LIMITED)
> +               return false;
> +       else if (vc4_state->broadcast_rgb == VC4_HDMI_BROADCAST_RGB_FULL)
> +               return true;
> +
>         return !display->is_hdmi ||
>                 drm_default_rgb_quant_range(mode) == HDMI_QUANTIZATION_RANGE_FULL;
>  }
> @@ -528,8 +534,12 @@ static int vc4_hdmi_connector_atomic_check(struct drm_connector *connector,
>  {
>         struct drm_connector_state *old_state =
>                 drm_atomic_get_old_connector_state(state, connector);
> +       struct vc4_hdmi_connector_state *old_vc4_state =
> +               conn_state_to_vc4_hdmi_conn_state(old_state);
>         struct drm_connector_state *new_state =
>                 drm_atomic_get_new_connector_state(state, connector);
> +       struct vc4_hdmi_connector_state *new_vc4_state =
> +               conn_state_to_vc4_hdmi_conn_state(new_state);
>         struct drm_crtc *crtc = new_state->crtc;
>
>         if (!crtc)
> @@ -562,6 +572,7 @@ static int vc4_hdmi_connector_atomic_check(struct drm_connector *connector,
>         }
>
>         if (old_state->colorspace != new_state->colorspace ||
> +           old_vc4_state->broadcast_rgb != new_vc4_state->broadcast_rgb ||
>             !drm_connector_atomic_hdr_metadata_equal(old_state, new_state)) {
>                 struct drm_crtc_state *crtc_state;
>
> @@ -575,6 +586,49 @@ static int vc4_hdmi_connector_atomic_check(struct drm_connector *connector,
>         return 0;
>  }
>
> +static int vc4_hdmi_connector_get_property(struct drm_connector *connector,
> +                                          const struct drm_connector_state *state,
> +                                          struct drm_property *property,
> +                                          uint64_t *val)
> +{
> +       struct drm_device *drm = connector->dev;
> +       struct vc4_hdmi *vc4_hdmi =
> +               connector_to_vc4_hdmi(connector);
> +       const struct vc4_hdmi_connector_state *vc4_conn_state =
> +               conn_state_to_vc4_hdmi_conn_state(state);
> +
> +       if (property == vc4_hdmi->broadcast_rgb_property) {
> +               *val = vc4_conn_state->broadcast_rgb;
> +       } else {
> +               drm_dbg(drm, "Unknown property [PROP:%d:%s]\n",
> +                       property->base.id, property->name);
> +               return -EINVAL;
> +       }
> +
> +       return 0;
> +}
> +
> +static int vc4_hdmi_connector_set_property(struct drm_connector *connector,
> +                                          struct drm_connector_state *state,
> +                                          struct drm_property *property,
> +                                          uint64_t val)
> +{
> +       struct drm_device *drm = connector->dev;
> +       struct vc4_hdmi *vc4_hdmi =
> +               connector_to_vc4_hdmi(connector);
> +       struct vc4_hdmi_connector_state *vc4_conn_state =
> +               conn_state_to_vc4_hdmi_conn_state(state);
> +
> +       if (property == vc4_hdmi->broadcast_rgb_property) {
> +               vc4_conn_state->broadcast_rgb = val;
> +               return 0;
> +       }
> +
> +       drm_dbg(drm, "Unknown property [PROP:%d:%s]\n",
> +               property->base.id, property->name);
> +       return -EINVAL;
> +}
> +
>  static void vc4_hdmi_connector_reset(struct drm_connector *connector)
>  {
>         struct vc4_hdmi_connector_state *old_state =
> @@ -594,6 +648,7 @@ static void vc4_hdmi_connector_reset(struct drm_connector *connector)
>         new_state->base.max_bpc = 8;
>         new_state->base.max_requested_bpc = 8;
>         new_state->output_format = VC4_HDMI_OUTPUT_RGB;
> +       new_state->broadcast_rgb = VC4_HDMI_BROADCAST_RGB_AUTO;
>         drm_atomic_helper_connector_tv_margins_reset(connector);
>  }
>
> @@ -611,6 +666,7 @@ vc4_hdmi_connector_duplicate_state(struct drm_connector *connector)
>         new_state->tmds_char_rate = vc4_state->tmds_char_rate;
>         new_state->output_bpc = vc4_state->output_bpc;
>         new_state->output_format = vc4_state->output_format;
> +       new_state->broadcast_rgb = vc4_state->broadcast_rgb;
>         __drm_atomic_helper_connector_duplicate_state(connector, &new_state->base);
>
>         return &new_state->base;
> @@ -621,6 +677,8 @@ static const struct drm_connector_funcs vc4_hdmi_connector_funcs = {
>         .reset = vc4_hdmi_connector_reset,
>         .atomic_duplicate_state = vc4_hdmi_connector_duplicate_state,
>         .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
> +       .atomic_get_property = vc4_hdmi_connector_get_property,
> +       .atomic_set_property = vc4_hdmi_connector_set_property,
>  };
>
>  static const struct drm_connector_helper_funcs vc4_hdmi_connector_helper_funcs = {
> @@ -629,6 +687,33 @@ static const struct drm_connector_helper_funcs vc4_hdmi_connector_helper_funcs =
>         .atomic_check = vc4_hdmi_connector_atomic_check,
>  };
>
> +static const struct drm_prop_enum_list broadcast_rgb_names[] = {
> +       { VC4_HDMI_BROADCAST_RGB_AUTO, "Automatic" },
> +       { VC4_HDMI_BROADCAST_RGB_FULL, "Full" },
> +       { VC4_HDMI_BROADCAST_RGB_LIMITED, "Limited 16:235" },
> +};
> +
> +static void
> +vc4_hdmi_attach_broadcast_rgb_property(struct drm_device *dev,
> +                                      struct vc4_hdmi *vc4_hdmi)
> +{
> +       struct drm_property *prop = vc4_hdmi->broadcast_rgb_property;
> +
> +       if (!prop) {
> +               prop = drm_property_create_enum(dev, DRM_MODE_PROP_ENUM,
> +                                               "Broadcast RGB",
> +                                               broadcast_rgb_names,
> +                                               ARRAY_SIZE(broadcast_rgb_names));
> +               if (!prop)
> +                       return;
> +
> +               vc4_hdmi->broadcast_rgb_property = prop;
> +       }
> +
> +       drm_object_attach_property(&vc4_hdmi->connector.base, prop,
> +                                  VC4_HDMI_BROADCAST_RGB_AUTO);
> +}
> +
>  static int vc4_hdmi_connector_init(struct drm_device *dev,
>                                    struct vc4_hdmi *vc4_hdmi)
>  {
> @@ -675,6 +760,8 @@ static int vc4_hdmi_connector_init(struct drm_device *dev,
>         if (vc4_hdmi->variant->supports_hdr)
>                 drm_connector_attach_hdr_output_metadata_property(connector);
>
> +       vc4_hdmi_attach_broadcast_rgb_property(dev, vc4_hdmi);
> +
>         drm_connector_attach_encoder(connector, encoder);
>
>         return 0;
> @@ -829,7 +916,7 @@ static void vc4_hdmi_set_avi_infoframe(struct drm_encoder *encoder)
>
>         drm_hdmi_avi_infoframe_quant_range(&frame.avi,
>                                            connector, mode,
> -                                          vc4_hdmi_is_full_range_rgb(vc4_hdmi, mode) ?
> +                                          vc4_hdmi_is_full_range_rgb(vc4_hdmi, vc4_state) ?
>                                            HDMI_QUANTIZATION_RANGE_FULL :
>                                            HDMI_QUANTIZATION_RANGE_LIMITED);
>         drm_hdmi_avi_infoframe_colorimetry(&frame.avi, cstate);
> @@ -1069,6 +1156,8 @@ static void vc4_hdmi_csc_setup(struct vc4_hdmi *vc4_hdmi,
>                                struct drm_connector_state *state,
>                                const struct drm_display_mode *mode)
>  {
> +       struct vc4_hdmi_connector_state *vc4_state =
> +               conn_state_to_vc4_hdmi_conn_state(state);
>         struct drm_device *drm = vc4_hdmi->connector.dev;
>         unsigned long flags;
>         u32 csc_ctl;
> @@ -1082,7 +1171,7 @@ static void vc4_hdmi_csc_setup(struct vc4_hdmi *vc4_hdmi,
>         csc_ctl = VC4_SET_FIELD(VC4_HD_CSC_CTL_ORDER_BGR,
>                                 VC4_HD_CSC_CTL_ORDER);
>
> -       if (!vc4_hdmi_is_full_range_rgb(vc4_hdmi, mode)) {
> +       if (!vc4_hdmi_is_full_range_rgb(vc4_hdmi, vc4_state)) {
>                 /* CEA VICs other than #1 requre limited range RGB
>                  * output unless overridden by an AVI infoframe.
>                  * Apply a colorspace conversion to squash 0-255 down
> @@ -1235,7 +1324,7 @@ static void vc5_hdmi_csc_setup(struct vc4_hdmi *vc4_hdmi,
>         case VC4_HDMI_OUTPUT_RGB:
>                 if_xbar = 0x354021;
>
> -               if (!vc4_hdmi_is_full_range_rgb(vc4_hdmi, mode))
> +               if (!vc4_hdmi_is_full_range_rgb(vc4_hdmi, vc4_state))
>                         vc5_hdmi_set_csc_coeffs(vc4_hdmi, vc5_hdmi_csc_full_rgb_to_limited_rgb);
>                 else
>                         vc5_hdmi_set_csc_coeffs(vc4_hdmi, vc5_hdmi_csc_full_rgb_unity);
> diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.h b/drivers/gpu/drm/vc4/vc4_hdmi.h
> index 5d249ac54cd1..89800c48aa24 100644
> --- a/drivers/gpu/drm/vc4/vc4_hdmi.h
> +++ b/drivers/gpu/drm/vc4/vc4_hdmi.h
> @@ -117,6 +117,12 @@ enum vc4_hdmi_output_format {
>         VC4_HDMI_OUTPUT_YUV420,
>  };
>
> +enum vc4_hdmi_broadcast_rgb {
> +       VC4_HDMI_BROADCAST_RGB_AUTO,
> +       VC4_HDMI_BROADCAST_RGB_FULL,
> +       VC4_HDMI_BROADCAST_RGB_LIMITED,
> +};
> +
>  /* General HDMI hardware state. */
>  struct vc4_hdmi {
>         struct vc4_hdmi_audio audio;
> @@ -129,6 +135,8 @@ struct vc4_hdmi {
>
>         struct delayed_work scrambling_work;
>
> +       struct drm_property *broadcast_rgb_property;
> +
>         struct i2c_adapter *ddc;
>         void __iomem *hdmicore_regs;
>         void __iomem *hd_regs;
> @@ -238,6 +246,7 @@ struct vc4_hdmi_connector_state {
>         unsigned long long              tmds_char_rate;
>         unsigned int                    output_bpc;
>         enum vc4_hdmi_output_format     output_format;
> +       enum vc4_hdmi_broadcast_rgb     broadcast_rgb;
>  };
>
>  #define conn_state_to_vc4_hdmi_conn_state(_state)                      \
>
> --
> 2.39.2
>
Maxime Ripard Oct. 19, 2023, 8:02 a.m. UTC | #2
Hi,

On Wed, Oct 11, 2023 at 03:23:18PM +0200, Daniel Vetter wrote:
> On Mon, 6 Mar 2023 at 11:49, Maxime Ripard <maxime@cerno.tech> wrote:
> >
> > From: Dave Stevenson <dave.stevenson@raspberrypi.com>
> >
> > Copy Intel's "Broadcast RGB" property semantics to add manual override
> > of the HDMI pixel range for monitors that don't abide by the content
> > of the AVI Infoframe.
> >
> > Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
> > Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> 
> Stumbled over this grepping around, but would have been nice to lift
> this into drm code and document the property. It's one of the legacy
> ones from the table of horrors after all ...
> 
> Shouldn't be an uapi problem because it's copypasted to much, just not great.

We already discussed it on IRC, but just for the record I have a current
series that should address exactly that:

https://lore.kernel.org/dri-devel/20230920-kms-hdmi-connector-state-v2-3-17932daddd7d@kernel.org/

Maxime
Hans Verkuil Oct. 19, 2023, 8:26 a.m. UTC | #3
Hi Maxime,

On 19/10/2023 10:02, Maxime Ripard wrote:
> Hi,
> 
> On Wed, Oct 11, 2023 at 03:23:18PM +0200, Daniel Vetter wrote:
>> On Mon, 6 Mar 2023 at 11:49, Maxime Ripard <maxime@cerno.tech> wrote:
>>>
>>> From: Dave Stevenson <dave.stevenson@raspberrypi.com>
>>>
>>> Copy Intel's "Broadcast RGB" property semantics to add manual override
>>> of the HDMI pixel range for monitors that don't abide by the content
>>> of the AVI Infoframe.
>>>
>>> Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
>>> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
>>
>> Stumbled over this grepping around, but would have been nice to lift
>> this into drm code and document the property. It's one of the legacy
>> ones from the table of horrors after all ...
>>
>> Shouldn't be an uapi problem because it's copypasted to much, just not great.
> 
> We already discussed it on IRC, but just for the record I have a current
> series that should address exactly that:
> 
> https://lore.kernel.org/dri-devel/20230920-kms-hdmi-connector-state-v2-3-17932daddd7d@kernel.org/
> 
> Maxime

I've pasted a snippet from that patch below for a quick review:

>  /**
>   * DOC: HDMI connector properties
>   *
> + * Broadcast RGB (HDMI Specific):

Full vs Limited is actually not HDMI specific, DisplayPort can signal this as
well for whatever it is worth.

> + *      Indicates the RGB Range (Full vs Limited) used.

RGB Range -> RGB Quantization Range

> + *
> + *      The value of this property can be one of the following:
> + *
> + *      Automatic:
> + *              RGB Range is selected automatically based on the mode
> + *              according to the HDMI specifications.
> + *
> + *      Full:
> + *              Full RGB Range is forced.
> + *
> + *      Limited 16:235:

It is very unfortunate that this is called "Limited 16:235" instead of just "Limited"
since for color component bit depths > 8 these values are different.

I have no idea if it is possible to add an alias "Limited" that you can use instead.
In any case, this should document that it works just as well for higher bit depths,
but with different limits.

Regards,

	Hans

> + *              Limited RGB Range is forced.
> + *
> + *      Drivers can set up this property by calling
> + *      drm_connector_attach_broadcast_rgb_property().
> + *
>   * content type (HDMI specific):
>   *	Indicates content type setting to be used in HDMI infoframes to indicate
>   *	content type for the external device, so that it adjusts its display
Maxime Ripard Oct. 23, 2023, 2:58 p.m. UTC | #4
Hi Hans,

On Thu, Oct 19, 2023 at 10:26:40AM +0200, Hans Verkuil wrote:
> Hi Maxime,
> 
> On 19/10/2023 10:02, Maxime Ripard wrote:
> > Hi,
> > 
> > On Wed, Oct 11, 2023 at 03:23:18PM +0200, Daniel Vetter wrote:
> >> On Mon, 6 Mar 2023 at 11:49, Maxime Ripard <maxime@cerno.tech> wrote:
> >>>
> >>> From: Dave Stevenson <dave.stevenson@raspberrypi.com>
> >>>
> >>> Copy Intel's "Broadcast RGB" property semantics to add manual override
> >>> of the HDMI pixel range for monitors that don't abide by the content
> >>> of the AVI Infoframe.
> >>>
> >>> Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
> >>> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> >>
> >> Stumbled over this grepping around, but would have been nice to lift
> >> this into drm code and document the property. It's one of the legacy
> >> ones from the table of horrors after all ...
> >>
> >> Shouldn't be an uapi problem because it's copypasted to much, just not great.
> > 
> > We already discussed it on IRC, but just for the record I have a current
> > series that should address exactly that:
> > 
> > https://lore.kernel.org/dri-devel/20230920-kms-hdmi-connector-state-v2-3-17932daddd7d@kernel.org/
> > 
> > Maxime
> 
> I've pasted a snippet from that patch below for a quick review:
> 
> >  /**
> >   * DOC: HDMI connector properties
> >   *
> > + * Broadcast RGB (HDMI Specific):
> 
> Full vs Limited is actually not HDMI specific, DisplayPort can signal this as
> well for whatever it is worth.

Sure, what I (and the original patch I guess) meant is that it's only
ever used on HDMI connectors these days. If that ever changes, then we
can update the doc.

> > + *      Indicates the RGB Range (Full vs Limited) used.
> 
> RGB Range -> RGB Quantization Range
> 
> > + *
> > + *      The value of this property can be one of the following:
> > + *
> > + *      Automatic:
> > + *              RGB Range is selected automatically based on the mode
> > + *              according to the HDMI specifications.
> > + *
> > + *      Full:
> > + *              Full RGB Range is forced.
> > + *
> > + *      Limited 16:235:
> 
> It is very unfortunate that this is called "Limited 16:235" instead of just "Limited"
> since for color component bit depths > 8 these values are different.
> 
> I have no idea if it is possible to add an alias "Limited" that you can use instead.
> In any case, this should document that it works just as well for higher bit depths,
> but with different limits.

I had a look and it doesn't look like the property infrastructure can
deal with aliases. I'll add something in the doc

Thanks!
Maxime
Sebastian Wick Oct. 23, 2023, 4:22 p.m. UTC | #5
Honestly, the less time people spend on this property the better. Lift
the Intel one into core and be done with it. We'll hopefully be able
to remove it in the not-to-distant future with the new color pipeline
API and adding a new property which only sets the connector metadata
instead of influencing the color pipeline as well.

On Mon, Oct 23, 2023 at 4:58 PM Maxime Ripard <maxime@cerno.tech> wrote:
>
> Hi Hans,
>
> On Thu, Oct 19, 2023 at 10:26:40AM +0200, Hans Verkuil wrote:
> > Hi Maxime,
> >
> > On 19/10/2023 10:02, Maxime Ripard wrote:
> > > Hi,
> > >
> > > On Wed, Oct 11, 2023 at 03:23:18PM +0200, Daniel Vetter wrote:
> > >> On Mon, 6 Mar 2023 at 11:49, Maxime Ripard <maxime@cerno.tech> wrote:
> > >>>
> > >>> From: Dave Stevenson <dave.stevenson@raspberrypi.com>
> > >>>
> > >>> Copy Intel's "Broadcast RGB" property semantics to add manual override
> > >>> of the HDMI pixel range for monitors that don't abide by the content
> > >>> of the AVI Infoframe.
> > >>>
> > >>> Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
> > >>> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> > >>
> > >> Stumbled over this grepping around, but would have been nice to lift
> > >> this into drm code and document the property. It's one of the legacy
> > >> ones from the table of horrors after all ...
> > >>
> > >> Shouldn't be an uapi problem because it's copypasted to much, just not great.
> > >
> > > We already discussed it on IRC, but just for the record I have a current
> > > series that should address exactly that:
> > >
> > > https://lore.kernel.org/dri-devel/20230920-kms-hdmi-connector-state-v2-3-17932daddd7d@kernel.org/
> > >
> > > Maxime
> >
> > I've pasted a snippet from that patch below for a quick review:
> >
> > >  /**
> > >   * DOC: HDMI connector properties
> > >   *
> > > + * Broadcast RGB (HDMI Specific):
> >
> > Full vs Limited is actually not HDMI specific, DisplayPort can signal this as
> > well for whatever it is worth.
>
> Sure, what I (and the original patch I guess) meant is that it's only
> ever used on HDMI connectors these days. If that ever changes, then we
> can update the doc.
>
> > > + *      Indicates the RGB Range (Full vs Limited) used.
> >
> > RGB Range -> RGB Quantization Range
> >
> > > + *
> > > + *      The value of this property can be one of the following:
> > > + *
> > > + *      Automatic:
> > > + *              RGB Range is selected automatically based on the mode
> > > + *              according to the HDMI specifications.
> > > + *
> > > + *      Full:
> > > + *              Full RGB Range is forced.
> > > + *
> > > + *      Limited 16:235:
> >
> > It is very unfortunate that this is called "Limited 16:235" instead of just "Limited"
> > since for color component bit depths > 8 these values are different.
> >
> > I have no idea if it is possible to add an alias "Limited" that you can use instead.
> > In any case, this should document that it works just as well for higher bit depths,
> > but with different limits.
>
> I had a look and it doesn't look like the property infrastructure can
> deal with aliases. I'll add something in the doc
>
> Thanks!
> Maxime
diff mbox series

Patch

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index 522cfbc83fe4..d23c0c3df2ee 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -154,10 +154,16 @@  static bool vc4_hdmi_mode_needs_scrambling(const struct drm_display_mode *mode,
 }
 
 static bool vc4_hdmi_is_full_range_rgb(struct vc4_hdmi *vc4_hdmi,
-				       const struct drm_display_mode *mode)
+				       struct vc4_hdmi_connector_state *vc4_state)
 {
+	const struct drm_display_mode *mode = &vc4_hdmi->saved_adjusted_mode;
 	struct drm_display_info *display = &vc4_hdmi->connector.display_info;
 
+	if (vc4_state->broadcast_rgb == VC4_HDMI_BROADCAST_RGB_LIMITED)
+		return false;
+	else if (vc4_state->broadcast_rgb == VC4_HDMI_BROADCAST_RGB_FULL)
+		return true;
+
 	return !display->is_hdmi ||
 		drm_default_rgb_quant_range(mode) == HDMI_QUANTIZATION_RANGE_FULL;
 }
@@ -528,8 +534,12 @@  static int vc4_hdmi_connector_atomic_check(struct drm_connector *connector,
 {
 	struct drm_connector_state *old_state =
 		drm_atomic_get_old_connector_state(state, connector);
+	struct vc4_hdmi_connector_state *old_vc4_state =
+		conn_state_to_vc4_hdmi_conn_state(old_state);
 	struct drm_connector_state *new_state =
 		drm_atomic_get_new_connector_state(state, connector);
+	struct vc4_hdmi_connector_state *new_vc4_state =
+		conn_state_to_vc4_hdmi_conn_state(new_state);
 	struct drm_crtc *crtc = new_state->crtc;
 
 	if (!crtc)
@@ -562,6 +572,7 @@  static int vc4_hdmi_connector_atomic_check(struct drm_connector *connector,
 	}
 
 	if (old_state->colorspace != new_state->colorspace ||
+	    old_vc4_state->broadcast_rgb != new_vc4_state->broadcast_rgb ||
 	    !drm_connector_atomic_hdr_metadata_equal(old_state, new_state)) {
 		struct drm_crtc_state *crtc_state;
 
@@ -575,6 +586,49 @@  static int vc4_hdmi_connector_atomic_check(struct drm_connector *connector,
 	return 0;
 }
 
+static int vc4_hdmi_connector_get_property(struct drm_connector *connector,
+					   const struct drm_connector_state *state,
+					   struct drm_property *property,
+					   uint64_t *val)
+{
+	struct drm_device *drm = connector->dev;
+	struct vc4_hdmi *vc4_hdmi =
+		connector_to_vc4_hdmi(connector);
+	const struct vc4_hdmi_connector_state *vc4_conn_state =
+		conn_state_to_vc4_hdmi_conn_state(state);
+
+	if (property == vc4_hdmi->broadcast_rgb_property) {
+		*val = vc4_conn_state->broadcast_rgb;
+	} else {
+		drm_dbg(drm, "Unknown property [PROP:%d:%s]\n",
+			property->base.id, property->name);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int vc4_hdmi_connector_set_property(struct drm_connector *connector,
+					   struct drm_connector_state *state,
+					   struct drm_property *property,
+					   uint64_t val)
+{
+	struct drm_device *drm = connector->dev;
+	struct vc4_hdmi *vc4_hdmi =
+		connector_to_vc4_hdmi(connector);
+	struct vc4_hdmi_connector_state *vc4_conn_state =
+		conn_state_to_vc4_hdmi_conn_state(state);
+
+	if (property == vc4_hdmi->broadcast_rgb_property) {
+		vc4_conn_state->broadcast_rgb = val;
+		return 0;
+	}
+
+	drm_dbg(drm, "Unknown property [PROP:%d:%s]\n",
+		property->base.id, property->name);
+	return -EINVAL;
+}
+
 static void vc4_hdmi_connector_reset(struct drm_connector *connector)
 {
 	struct vc4_hdmi_connector_state *old_state =
@@ -594,6 +648,7 @@  static void vc4_hdmi_connector_reset(struct drm_connector *connector)
 	new_state->base.max_bpc = 8;
 	new_state->base.max_requested_bpc = 8;
 	new_state->output_format = VC4_HDMI_OUTPUT_RGB;
+	new_state->broadcast_rgb = VC4_HDMI_BROADCAST_RGB_AUTO;
 	drm_atomic_helper_connector_tv_margins_reset(connector);
 }
 
@@ -611,6 +666,7 @@  vc4_hdmi_connector_duplicate_state(struct drm_connector *connector)
 	new_state->tmds_char_rate = vc4_state->tmds_char_rate;
 	new_state->output_bpc = vc4_state->output_bpc;
 	new_state->output_format = vc4_state->output_format;
+	new_state->broadcast_rgb = vc4_state->broadcast_rgb;
 	__drm_atomic_helper_connector_duplicate_state(connector, &new_state->base);
 
 	return &new_state->base;
@@ -621,6 +677,8 @@  static const struct drm_connector_funcs vc4_hdmi_connector_funcs = {
 	.reset = vc4_hdmi_connector_reset,
 	.atomic_duplicate_state = vc4_hdmi_connector_duplicate_state,
 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+	.atomic_get_property = vc4_hdmi_connector_get_property,
+	.atomic_set_property = vc4_hdmi_connector_set_property,
 };
 
 static const struct drm_connector_helper_funcs vc4_hdmi_connector_helper_funcs = {
@@ -629,6 +687,33 @@  static const struct drm_connector_helper_funcs vc4_hdmi_connector_helper_funcs =
 	.atomic_check = vc4_hdmi_connector_atomic_check,
 };
 
+static const struct drm_prop_enum_list broadcast_rgb_names[] = {
+	{ VC4_HDMI_BROADCAST_RGB_AUTO, "Automatic" },
+	{ VC4_HDMI_BROADCAST_RGB_FULL, "Full" },
+	{ VC4_HDMI_BROADCAST_RGB_LIMITED, "Limited 16:235" },
+};
+
+static void
+vc4_hdmi_attach_broadcast_rgb_property(struct drm_device *dev,
+				       struct vc4_hdmi *vc4_hdmi)
+{
+	struct drm_property *prop = vc4_hdmi->broadcast_rgb_property;
+
+	if (!prop) {
+		prop = drm_property_create_enum(dev, DRM_MODE_PROP_ENUM,
+						"Broadcast RGB",
+						broadcast_rgb_names,
+						ARRAY_SIZE(broadcast_rgb_names));
+		if (!prop)
+			return;
+
+		vc4_hdmi->broadcast_rgb_property = prop;
+	}
+
+	drm_object_attach_property(&vc4_hdmi->connector.base, prop,
+				   VC4_HDMI_BROADCAST_RGB_AUTO);
+}
+
 static int vc4_hdmi_connector_init(struct drm_device *dev,
 				   struct vc4_hdmi *vc4_hdmi)
 {
@@ -675,6 +760,8 @@  static int vc4_hdmi_connector_init(struct drm_device *dev,
 	if (vc4_hdmi->variant->supports_hdr)
 		drm_connector_attach_hdr_output_metadata_property(connector);
 
+	vc4_hdmi_attach_broadcast_rgb_property(dev, vc4_hdmi);
+
 	drm_connector_attach_encoder(connector, encoder);
 
 	return 0;
@@ -829,7 +916,7 @@  static void vc4_hdmi_set_avi_infoframe(struct drm_encoder *encoder)
 
 	drm_hdmi_avi_infoframe_quant_range(&frame.avi,
 					   connector, mode,
-					   vc4_hdmi_is_full_range_rgb(vc4_hdmi, mode) ?
+					   vc4_hdmi_is_full_range_rgb(vc4_hdmi, vc4_state) ?
 					   HDMI_QUANTIZATION_RANGE_FULL :
 					   HDMI_QUANTIZATION_RANGE_LIMITED);
 	drm_hdmi_avi_infoframe_colorimetry(&frame.avi, cstate);
@@ -1069,6 +1156,8 @@  static void vc4_hdmi_csc_setup(struct vc4_hdmi *vc4_hdmi,
 			       struct drm_connector_state *state,
 			       const struct drm_display_mode *mode)
 {
+	struct vc4_hdmi_connector_state *vc4_state =
+		conn_state_to_vc4_hdmi_conn_state(state);
 	struct drm_device *drm = vc4_hdmi->connector.dev;
 	unsigned long flags;
 	u32 csc_ctl;
@@ -1082,7 +1171,7 @@  static void vc4_hdmi_csc_setup(struct vc4_hdmi *vc4_hdmi,
 	csc_ctl = VC4_SET_FIELD(VC4_HD_CSC_CTL_ORDER_BGR,
 				VC4_HD_CSC_CTL_ORDER);
 
-	if (!vc4_hdmi_is_full_range_rgb(vc4_hdmi, mode)) {
+	if (!vc4_hdmi_is_full_range_rgb(vc4_hdmi, vc4_state)) {
 		/* CEA VICs other than #1 requre limited range RGB
 		 * output unless overridden by an AVI infoframe.
 		 * Apply a colorspace conversion to squash 0-255 down
@@ -1235,7 +1324,7 @@  static void vc5_hdmi_csc_setup(struct vc4_hdmi *vc4_hdmi,
 	case VC4_HDMI_OUTPUT_RGB:
 		if_xbar = 0x354021;
 
-		if (!vc4_hdmi_is_full_range_rgb(vc4_hdmi, mode))
+		if (!vc4_hdmi_is_full_range_rgb(vc4_hdmi, vc4_state))
 			vc5_hdmi_set_csc_coeffs(vc4_hdmi, vc5_hdmi_csc_full_rgb_to_limited_rgb);
 		else
 			vc5_hdmi_set_csc_coeffs(vc4_hdmi, vc5_hdmi_csc_full_rgb_unity);
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.h b/drivers/gpu/drm/vc4/vc4_hdmi.h
index 5d249ac54cd1..89800c48aa24 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.h
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.h
@@ -117,6 +117,12 @@  enum vc4_hdmi_output_format {
 	VC4_HDMI_OUTPUT_YUV420,
 };
 
+enum vc4_hdmi_broadcast_rgb {
+	VC4_HDMI_BROADCAST_RGB_AUTO,
+	VC4_HDMI_BROADCAST_RGB_FULL,
+	VC4_HDMI_BROADCAST_RGB_LIMITED,
+};
+
 /* General HDMI hardware state. */
 struct vc4_hdmi {
 	struct vc4_hdmi_audio audio;
@@ -129,6 +135,8 @@  struct vc4_hdmi {
 
 	struct delayed_work scrambling_work;
 
+	struct drm_property *broadcast_rgb_property;
+
 	struct i2c_adapter *ddc;
 	void __iomem *hdmicore_regs;
 	void __iomem *hd_regs;
@@ -238,6 +246,7 @@  struct vc4_hdmi_connector_state {
 	unsigned long long		tmds_char_rate;
 	unsigned int 			output_bpc;
 	enum vc4_hdmi_output_format	output_format;
+	enum vc4_hdmi_broadcast_rgb	broadcast_rgb;
 };
 
 #define conn_state_to_vc4_hdmi_conn_state(_state)			\