[PATCH v3 0/2] Fix ycbcr_420_allowed inconsistency for HDMI bridges

[PATCH v3 0/2] Fix ycbcr_420_allowed inconsistency for HDMI bridges

[Cristian Ciocaltea]

Bridges with DRM_BRIDGE_OP_HDMI set in drm_bridge->ops are expected to
rely on drm_bridge->supported_formats to advertise the supported
colorspaces, including HDMI_COLORSPACE_YUV420.

However, when drm_bridge_connector gets initialised, only
drm_bridge->ycbcr_420_allowed is considered in the process of adjusting
the drm_connector->ycbcr_420_allowed, which effectively discards the
formats advertised by the HDMI bridge.

This patchset tries to address the issue by prioritizing
supported_formats over ycbcr_420_allowed.

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
---
Changes in v3:
- Simplified the inconsistency handling by overwriting ycbcr_420_allowed
  for HDMI bridges before adding them to the global bridge list
- Added a 2nd patch to check if supported_formats matches
  ycbcr_420_allowed on HDMI connector initialization (Dmitry)
- Link to v2: https://lore.kernel.org/r/20241206-bridge-conn-fmt-prio-v2-1-85c817529b88@collabora.com

Changes in v2:
- Wrapped HDMI_COLORSPACE_YUV420 flag in the BIT() macro to properly
  check its presence in supported_formats
- Ensured YUV420 gets removed from the bitmask passed to
  drmm_connector_hdmi_init() when ycbcr_420_allowed is not set
- Link to v1: https://lore.kernel.org/r/20241130-bridge-conn-fmt-prio-v1-1-146b663f17f3@collabora.com

---
Cristian Ciocaltea (2):
      drm/bridge-connector: Prioritize supported_formats over ycbcr_420_allowed
      drm/connector: hdmi: Validate supported_formats matches ycbcr_420_allowed

 drivers/gpu/drm/display/drm_bridge_connector.c | 8 ++++++--
 drivers/gpu/drm/drm_bridge.c                   | 4 ++++
 drivers/gpu/drm/drm_connector.c                | 3 +++
 3 files changed, 13 insertions(+), 2 deletions(-)
---
base-commit: f486c8aa16b8172f63bddc70116a0c897a7f3f02
change-id: 20241130-bridge-conn-fmt-prio-c517c1407ed5

[PATCH v3 1/2] drm/bridge-connector: Prioritize supported_formats over ycbcr_420_allowed

[Cristian Ciocaltea]

Bridges having the DRM_BRIDGE_OP_HDMI flag set in drm_bridge->ops are
supposed to rely on drm_bridge->supported_formats bitmask to advertise
the supported colorspaces, including HDMI_COLORSPACE_YUV420.  Therefore,
the newly introduced drm_bridge->ycbcr_420_allowed flag becomes
redundant in this particular context.

Moreover, when drm_bridge_connector gets initialised, only
drm_bridge->ycbcr_420_allowed is considered in the process of adjusting
the equivalent property of the base drm_connector, which effectively
discards the formats advertised by the HDMI bridge.

Handle the inconsistency by overwriting drm_bridge->ycbcr_420_allowed
for HDMI bridges according to drm_bridge->supported_formats, before
adding them to the global bridge list.

Additionally, ensure the YUV420 related bit is removed from the bitmask
passed to drmm_connector_hdmi_init() when the final ycbcr_420_allowed
flag for the connector ends up not being set (i.e. the case of having at
least one non-HDMI bridge in the pipeline that didn't enable it).

Fixes: 3ced1c687512 ("drm/display: bridge_connector: handle ycbcr_420_allowed")
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
---
 drivers/gpu/drm/display/drm_bridge_connector.c | 8 ++++++--
 drivers/gpu/drm/drm_bridge.c                   | 4 ++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/drm/display/drm_bridge_connector.c
index 320c297008aaa8b6ef5b1f4c71928849b202e8ac..3a5a4f92c979accaa2a8f79ca0f15396dd579429 100644
--- a/drivers/gpu/drm/display/drm_bridge_connector.c
+++ b/drivers/gpu/drm/display/drm_bridge_connector.c
@@ -459,7 +459,10 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 	if (connector_type == DRM_MODE_CONNECTOR_Unknown)
 		return ERR_PTR(-EINVAL);
 
-	if (bridge_connector->bridge_hdmi)
+	if (bridge_connector->bridge_hdmi) {
+		if (!connector->ycbcr_420_allowed)
+			supported_formats &= ~BIT(HDMI_COLORSPACE_YUV420);
+
 		ret = drmm_connector_hdmi_init(drm, connector,
 					       bridge_connector->bridge_hdmi->vendor,
 					       bridge_connector->bridge_hdmi->product,
@@ -468,10 +471,11 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 					       connector_type, ddc,
 					       supported_formats,
 					       max_bpc);
-	else
+	} else {
 		ret = drmm_connector_init(drm, connector,
 					  &drm_bridge_connector_funcs,
 					  connector_type, ddc);
+	}
 	if (ret)
 		return ERR_PTR(ret);
 
diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index c6af46dd02bfa9e15b59e4c460debdd7fd84be44..241a384ebce39b4a3db58c208af27960904fc662 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -207,6 +207,10 @@ void drm_bridge_add(struct drm_bridge *bridge)
 {
 	mutex_init(&bridge->hpd_mutex);
 
+	if (bridge->ops & DRM_BRIDGE_OP_HDMI)
+		bridge->ycbcr_420_allowed = !!(bridge->supported_formats &
+					       BIT(HDMI_COLORSPACE_YUV420));
+
 	mutex_lock(&bridge_lock);
 	list_add_tail(&bridge->list, &bridge_list);
 	mutex_unlock(&bridge_lock);

-- 
2.47.0

Re: [PATCH v3 1/2] drm/bridge-connector: Prioritize supported_formats over ycbcr_420_allowed

[Dmitry Baryshkov]

On Tue, Dec 17, 2024 at 12:54:07AM +0200, Cristian Ciocaltea wrote:
> Bridges having the DRM_BRIDGE_OP_HDMI flag set in drm_bridge->ops are
> supposed to rely on drm_bridge->supported_formats bitmask to advertise
> the supported colorspaces, including HDMI_COLORSPACE_YUV420.  Therefore,
> the newly introduced drm_bridge->ycbcr_420_allowed flag becomes
> redundant in this particular context.
> 
> Moreover, when drm_bridge_connector gets initialised, only
> drm_bridge->ycbcr_420_allowed is considered in the process of adjusting
> the equivalent property of the base drm_connector, which effectively
> discards the formats advertised by the HDMI bridge.
> 
> Handle the inconsistency by overwriting drm_bridge->ycbcr_420_allowed
> for HDMI bridges according to drm_bridge->supported_formats, before
> adding them to the global bridge list.
> 
> Additionally, ensure the YUV420 related bit is removed from the bitmask
> passed to drmm_connector_hdmi_init() when the final ycbcr_420_allowed
> flag for the connector ends up not being set (i.e. the case of having at
> least one non-HDMI bridge in the pipeline that didn't enable it).
> 
> Fixes: 3ced1c687512 ("drm/display: bridge_connector: handle ycbcr_420_allowed")
> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
> ---
>  drivers/gpu/drm/display/drm_bridge_connector.c | 8 ++++++--
>  drivers/gpu/drm/drm_bridge.c                   | 4 ++++
>  2 files changed, 10 insertions(+), 2 deletions(-)

I think the second patch in the series is enough, it ensures that
connector's state is consistent, no matter if the drm_bridge_connector
is being used or a normal drm_connector.

Nevertheless, I'd leave the final decision to DRM maintainers.

-- 
With best wishes
Dmitry

Re: [PATCH v3 1/2] drm/bridge-connector: Prioritize supported_formats over ycbcr_420_allowed

[Cristian Ciocaltea]

On 12/17/24 1:27 AM, Dmitry Baryshkov wrote:
> On Tue, Dec 17, 2024 at 12:54:07AM +0200, Cristian Ciocaltea wrote:
>> Bridges having the DRM_BRIDGE_OP_HDMI flag set in drm_bridge->ops are
>> supposed to rely on drm_bridge->supported_formats bitmask to advertise
>> the supported colorspaces, including HDMI_COLORSPACE_YUV420.  Therefore,
>> the newly introduced drm_bridge->ycbcr_420_allowed flag becomes
>> redundant in this particular context.
>>
>> Moreover, when drm_bridge_connector gets initialised, only
>> drm_bridge->ycbcr_420_allowed is considered in the process of adjusting
>> the equivalent property of the base drm_connector, which effectively
>> discards the formats advertised by the HDMI bridge.
>>
>> Handle the inconsistency by overwriting drm_bridge->ycbcr_420_allowed
>> for HDMI bridges according to drm_bridge->supported_formats, before
>> adding them to the global bridge list.
>>
>> Additionally, ensure the YUV420 related bit is removed from the bitmask
>> passed to drmm_connector_hdmi_init() when the final ycbcr_420_allowed
>> flag for the connector ends up not being set (i.e. the case of having at
>> least one non-HDMI bridge in the pipeline that didn't enable it).
>>
>> Fixes: 3ced1c687512 ("drm/display: bridge_connector: handle ycbcr_420_allowed")
>> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
>> ---
>>  drivers/gpu/drm/display/drm_bridge_connector.c | 8 ++++++--
>>  drivers/gpu/drm/drm_bridge.c                   | 4 ++++
>>  2 files changed, 10 insertions(+), 2 deletions(-)
> 
> I think the second patch in the series is enough, it ensures that
> connector's state is consistent, no matter if the drm_bridge_connector
> is being used or a normal drm_connector.
> 
> Nevertheless, I'd leave the final decision to DRM maintainers.

This patch has 2 parts, maybe I should have put them into separate patches
as they kind of relate to distinct problems.

The 1st part makes sure that drm_bridge->ycbcr_420_allowed is automatically
set when HDMI_COLORSPACE_YUV420 is provided in drm_bridge->supported_formats, 
to avoid the need of requiring redundant information on HDMI bridges 
initialization.  This implicitly ensures the consistency needed to further 
allow relying on ->ycbcr_420_allowed internally.

While the 1st part could be dropped (assuming redundancy & consistency is
not really something we want/need to handle), the 2nd part I think is
mandatory, i.e. we must adjust supported_formats before calling
drmm_connector_hdmi_init() to ensure the presence of HDMI_COLORSPACE_YUV420
reflects the status of the computed connector->ycbcr_420_allowed, which
might end up being different than what the HDMI bridge advertised, i.e. the
case of having an HDMI bridge in the pipeline advertising YUV420 via 
supported_formats and a non-HDMI one that didn't enable ycbcr_420_allowed.

Thanks,
Cristian

Re: [PATCH v3 1/2] drm/bridge-connector: Prioritize supported_formats over ycbcr_420_allowed

[Dmitry Baryshkov]

On Tue, Dec 17, 2024 at 02:38:55AM +0200, Cristian Ciocaltea wrote:
> On 12/17/24 1:27 AM, Dmitry Baryshkov wrote:
> > On Tue, Dec 17, 2024 at 12:54:07AM +0200, Cristian Ciocaltea wrote:
> >> Bridges having the DRM_BRIDGE_OP_HDMI flag set in drm_bridge->ops are
> >> supposed to rely on drm_bridge->supported_formats bitmask to advertise
> >> the supported colorspaces, including HDMI_COLORSPACE_YUV420.  Therefore,
> >> the newly introduced drm_bridge->ycbcr_420_allowed flag becomes
> >> redundant in this particular context.
> >>
> >> Moreover, when drm_bridge_connector gets initialised, only
> >> drm_bridge->ycbcr_420_allowed is considered in the process of adjusting
> >> the equivalent property of the base drm_connector, which effectively
> >> discards the formats advertised by the HDMI bridge.
> >>
> >> Handle the inconsistency by overwriting drm_bridge->ycbcr_420_allowed
> >> for HDMI bridges according to drm_bridge->supported_formats, before
> >> adding them to the global bridge list.
> >>
> >> Additionally, ensure the YUV420 related bit is removed from the bitmask
> >> passed to drmm_connector_hdmi_init() when the final ycbcr_420_allowed
> >> flag for the connector ends up not being set (i.e. the case of having at
> >> least one non-HDMI bridge in the pipeline that didn't enable it).
> >>
> >> Fixes: 3ced1c687512 ("drm/display: bridge_connector: handle ycbcr_420_allowed")
> >> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
> >> ---
> >>  drivers/gpu/drm/display/drm_bridge_connector.c | 8 ++++++--
> >>  drivers/gpu/drm/drm_bridge.c                   | 4 ++++
> >>  2 files changed, 10 insertions(+), 2 deletions(-)
> > 
> > I think the second patch in the series is enough, it ensures that
> > connector's state is consistent, no matter if the drm_bridge_connector
> > is being used or a normal drm_connector.
> > 
> > Nevertheless, I'd leave the final decision to DRM maintainers.
> 
> This patch has 2 parts, maybe I should have put them into separate patches
> as they kind of relate to distinct problems.
> 
> The 1st part makes sure that drm_bridge->ycbcr_420_allowed is automatically
> set when HDMI_COLORSPACE_YUV420 is provided in drm_bridge->supported_formats, 
> to avoid the need of requiring redundant information on HDMI bridges 
> initialization.  This implicitly ensures the consistency needed to further 
> allow relying on ->ycbcr_420_allowed internally.
> 
> While the 1st part could be dropped (assuming redundancy & consistency is
> not really something we want/need to handle), the 2nd part I think is
> mandatory, i.e. we must adjust supported_formats before calling
> drmm_connector_hdmi_init() to ensure the presence of HDMI_COLORSPACE_YUV420
> reflects the status of the computed connector->ycbcr_420_allowed, which
> might end up being different than what the HDMI bridge advertised, i.e. the
> case of having an HDMI bridge in the pipeline advertising YUV420 via 
> supported_formats and a non-HDMI one that didn't enable ycbcr_420_allowed.

Please split it into two patches. I don't have a strong opinion upon the
first one (I'd change it to dev_warn() maybe), while the second one
(removing HDMI_COLORSPACE_YUV420 if connector->ycbcr_420_allowed is
false) is definitely a correct change.

> 
> Thanks,
> Cristian

-- 
With best wishes
Dmitry

Re: [PATCH v3 1/2] drm/bridge-connector: Prioritize supported_formats over ycbcr_420_allowed

[Cristian Ciocaltea]

On 12/20/24 3:05 AM, Dmitry Baryshkov wrote:
> On Tue, Dec 17, 2024 at 02:38:55AM +0200, Cristian Ciocaltea wrote:
>> On 12/17/24 1:27 AM, Dmitry Baryshkov wrote:
>>> On Tue, Dec 17, 2024 at 12:54:07AM +0200, Cristian Ciocaltea wrote:
>>>> Bridges having the DRM_BRIDGE_OP_HDMI flag set in drm_bridge->ops are
>>>> supposed to rely on drm_bridge->supported_formats bitmask to advertise
>>>> the supported colorspaces, including HDMI_COLORSPACE_YUV420.  Therefore,
>>>> the newly introduced drm_bridge->ycbcr_420_allowed flag becomes
>>>> redundant in this particular context.
>>>>
>>>> Moreover, when drm_bridge_connector gets initialised, only
>>>> drm_bridge->ycbcr_420_allowed is considered in the process of adjusting
>>>> the equivalent property of the base drm_connector, which effectively
>>>> discards the formats advertised by the HDMI bridge.
>>>>
>>>> Handle the inconsistency by overwriting drm_bridge->ycbcr_420_allowed
>>>> for HDMI bridges according to drm_bridge->supported_formats, before
>>>> adding them to the global bridge list.
>>>>
>>>> Additionally, ensure the YUV420 related bit is removed from the bitmask
>>>> passed to drmm_connector_hdmi_init() when the final ycbcr_420_allowed
>>>> flag for the connector ends up not being set (i.e. the case of having at
>>>> least one non-HDMI bridge in the pipeline that didn't enable it).
>>>>
>>>> Fixes: 3ced1c687512 ("drm/display: bridge_connector: handle ycbcr_420_allowed")
>>>> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
>>>> ---
>>>>  drivers/gpu/drm/display/drm_bridge_connector.c | 8 ++++++--
>>>>  drivers/gpu/drm/drm_bridge.c                   | 4 ++++
>>>>  2 files changed, 10 insertions(+), 2 deletions(-)
>>>
>>> I think the second patch in the series is enough, it ensures that
>>> connector's state is consistent, no matter if the drm_bridge_connector
>>> is being used or a normal drm_connector.
>>>
>>> Nevertheless, I'd leave the final decision to DRM maintainers.
>>
>> This patch has 2 parts, maybe I should have put them into separate patches
>> as they kind of relate to distinct problems.
>>
>> The 1st part makes sure that drm_bridge->ycbcr_420_allowed is automatically
>> set when HDMI_COLORSPACE_YUV420 is provided in drm_bridge->supported_formats, 
>> to avoid the need of requiring redundant information on HDMI bridges 
>> initialization.  This implicitly ensures the consistency needed to further 
>> allow relying on ->ycbcr_420_allowed internally.
>>
>> While the 1st part could be dropped (assuming redundancy & consistency is
>> not really something we want/need to handle), the 2nd part I think is
>> mandatory, i.e. we must adjust supported_formats before calling
>> drmm_connector_hdmi_init() to ensure the presence of HDMI_COLORSPACE_YUV420
>> reflects the status of the computed connector->ycbcr_420_allowed, which
>> might end up being different than what the HDMI bridge advertised, i.e. the
>> case of having an HDMI bridge in the pipeline advertising YUV420 via 
>> supported_formats and a non-HDMI one that didn't enable ycbcr_420_allowed.
> 
> Please split it into two patches. I don't have a strong opinion upon the
> first one (I'd change it to dev_warn() maybe), while the second one
> (removing HDMI_COLORSPACE_YUV420 if connector->ycbcr_420_allowed is
> false) is definitely a correct change.

Split done in v4:

https://lore.kernel.org/lkml/20241224-bridge-conn-fmt-prio-v4-2-a9ceb5671379@collabora.com/

Thanks,
Cristian

[PATCH v3 2/2] drm/connector: hdmi: Validate supported_formats matches ycbcr_420_allowed

[Cristian Ciocaltea]

Ensure HDMI connector initialization fails when the presence of
HDMI_COLORSPACE_YUV420 in the given supported_formats bitmask doesn't
match the value of drm_connector->ycbcr_420_allowed.

Suggested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
---
 drivers/gpu/drm/drm_connector.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index fc35f47e2849ed6786d6223ac9c69e1c359fc648..ca7f43c8d6f1b31ef9d3a1ee05f4df930ecffac4 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -507,6 +507,9 @@ int drmm_connector_hdmi_init(struct drm_device *dev,
 	if (!supported_formats || !(supported_formats & BIT(HDMI_COLORSPACE_RGB)))
 		return -EINVAL;
 
+	if (connector->ycbcr_420_allowed != !!(supported_formats & BIT(HDMI_COLORSPACE_YUV420)))
+		return -EINVAL;
+
 	if (!(max_bpc == 8 || max_bpc == 10 || max_bpc == 12))
 		return -EINVAL;
 

-- 
2.47.0

Re: [PATCH v3 2/2] drm/connector: hdmi: Validate supported_formats matches ycbcr_420_allowed

[Dmitry Baryshkov]

On Tue, Dec 17, 2024 at 12:54:08AM +0200, Cristian Ciocaltea wrote:
> Ensure HDMI connector initialization fails when the presence of
> HDMI_COLORSPACE_YUV420 in the given supported_formats bitmask doesn't
> match the value of drm_connector->ycbcr_420_allowed.
> 
> Suggested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
> ---
>  drivers/gpu/drm/drm_connector.c | 3 +++
>  1 file changed, 3 insertions(+)
> 

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

-- 
With best wishes
Dmitry

Re: [PATCH v3 2/2] drm/connector: hdmi: Validate supported_formats matches ycbcr_420_allowed

[Maxime Ripard]

[-- Attachment #1: Type: text/plain, Size: 1237 bytes --]

On Tue, Dec 17, 2024 at 12:54:08AM +0200, Cristian Ciocaltea wrote:
> Ensure HDMI connector initialization fails when the presence of
> HDMI_COLORSPACE_YUV420 in the given supported_formats bitmask doesn't
> match the value of drm_connector->ycbcr_420_allowed.
> 
> Suggested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
> ---
>  drivers/gpu/drm/drm_connector.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> index fc35f47e2849ed6786d6223ac9c69e1c359fc648..ca7f43c8d6f1b31ef9d3a1ee05f4df930ecffac4 100644
> --- a/drivers/gpu/drm/drm_connector.c
> +++ b/drivers/gpu/drm/drm_connector.c
> @@ -507,6 +507,9 @@ int drmm_connector_hdmi_init(struct drm_device *dev,
>  	if (!supported_formats || !(supported_formats & BIT(HDMI_COLORSPACE_RGB)))
>  		return -EINVAL;
>  
> +	if (connector->ycbcr_420_allowed != !!(supported_formats & BIT(HDMI_COLORSPACE_YUV420)))
> +		return -EINVAL;
> +
>  	if (!(max_bpc == 8 || max_bpc == 10 || max_bpc == 12))
>  		return -EINVAL;

The patch looks fine to me, but we need to have unit tests to cover this case.

Maxime

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 273 bytes --]

Re: [PATCH v3 2/2] drm/connector: hdmi: Validate supported_formats matches ycbcr_420_allowed

[Cristian Ciocaltea]

On 12/17/24 5:25 PM, Maxime Ripard wrote:
> On Tue, Dec 17, 2024 at 12:54:08AM +0200, Cristian Ciocaltea wrote:
>> Ensure HDMI connector initialization fails when the presence of
>> HDMI_COLORSPACE_YUV420 in the given supported_formats bitmask doesn't
>> match the value of drm_connector->ycbcr_420_allowed.
>>
>> Suggested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
>> ---
>>  drivers/gpu/drm/drm_connector.c | 3 +++
>>  1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
>> index fc35f47e2849ed6786d6223ac9c69e1c359fc648..ca7f43c8d6f1b31ef9d3a1ee05f4df930ecffac4 100644
>> --- a/drivers/gpu/drm/drm_connector.c
>> +++ b/drivers/gpu/drm/drm_connector.c
>> @@ -507,6 +507,9 @@ int drmm_connector_hdmi_init(struct drm_device *dev,
>>  	if (!supported_formats || !(supported_formats & BIT(HDMI_COLORSPACE_RGB)))
>>  		return -EINVAL;
>>  
>> +	if (connector->ycbcr_420_allowed != !!(supported_formats & BIT(HDMI_COLORSPACE_YUV420)))
>> +		return -EINVAL;
>> +
>>  	if (!(max_bpc == 8 || max_bpc == 10 || max_bpc == 12))
>>  		return -EINVAL;
> 
> The patch looks fine to me, but we need to have unit tests to cover this case.

Unit tests added in v4:

https://lore.kernel.org/lkml/20241224-bridge-conn-fmt-prio-v4-4-a9ceb5671379@collabora.com/

Thanks,
Cristian