[PATCH 0/2] drm/bridge: tc358767: Fix DRM_BRIDGE_ATTACH_NO_CONNECTOR case

[PATCH 0/2] drm/bridge: tc358767: Fix DRM_BRIDGE_ATTACH_NO_CONNECTOR case

[Tomi Valkeinen]

These two patches are needed to make tc358767 work in the
DRM_BRIDGE_ATTACH_NO_CONNECTOR case, at least when using a DP connector.
The first patch, "drm/bridge: tc358767: Support input format negotiation
hook" was already sent separately, but I included it here for
completeness, as both are needed to get a working display.

I have tested this with TI AM654 EVM with a tc358767 add-on card.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
Aradhya Bhatia (1):
      drm/bridge: tc358767: Support input format negotiation hook

Tomi Valkeinen (1):
      drm/bridge: tc358767: Fix link properties discovery

 drivers/gpu/drm/bridge/tc358767.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)
---
base-commit: 79d94360d50fcd487edcfe118a47a2881534923f
change-id: 20231031-tc358767-58e3ebdf95f0

Best regards,
-- 
Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>

[PATCH 1/2] drm/bridge: tc358767: Support input format negotiation hook

[Tomi Valkeinen]

From: Aradhya Bhatia <a-bhatia1@ti.com>

With new connector model, tc358767 will not create the connector, when
DRM_BRIDGE_ATTACH_NO_CONNECTOR is set and display-controller driver will
rely on format negotiation to setup the encoder format.

Add the missing input-format negotiation hook in the
drm_bridge_funcs to complete DRM_BRIDGE_ATTACH_NO_CONNECTOR support.

Input format is selected to MEDIA_BUS_FMT_RGB888_1X24 as default, as is
the case with older model.

Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
Closes: https://lore.kernel.org/all/24282420-b4dd-45b3-bb1c-fc37fe4a8205@siemens.com/
Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/gpu/drm/bridge/tc358767.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
index ef2e373606ba..0affcefdeb1c 100644
--- a/drivers/gpu/drm/bridge/tc358767.c
+++ b/drivers/gpu/drm/bridge/tc358767.c
@@ -1751,6 +1751,30 @@ tc_dpi_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
 	return input_fmts;
 }
 
+static u32 *
+tc_edp_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
+				 struct drm_bridge_state *bridge_state,
+				 struct drm_crtc_state *crtc_state,
+				 struct drm_connector_state *conn_state,
+				 u32 output_fmt,
+				 unsigned int *num_input_fmts)
+{
+	u32 *input_fmts;
+
+	*num_input_fmts = 0;
+
+	input_fmts = kcalloc(MAX_INPUT_SEL_FORMATS, sizeof(*input_fmts),
+			     GFP_KERNEL);
+	if (!input_fmts)
+		return NULL;
+
+	/* This is the DSI/DPI-end bus format */
+	input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
+	*num_input_fmts = 1;
+
+	return input_fmts;
+}
+
 static const struct drm_bridge_funcs tc_dpi_bridge_funcs = {
 	.attach = tc_dpi_bridge_attach,
 	.mode_valid = tc_dpi_mode_valid,
@@ -1777,6 +1801,7 @@ static const struct drm_bridge_funcs tc_edp_bridge_funcs = {
 	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
 	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
 	.atomic_reset = drm_atomic_helper_bridge_reset,
+	.atomic_get_input_bus_fmts = tc_edp_atomic_get_input_bus_fmts,
 };
 
 static bool tc_readable_reg(struct device *dev, unsigned int reg)

-- 
2.34.1

[PATCH 2/2] drm/bridge: tc358767: Fix link properties discovery

[Tomi Valkeinen]

When a display controller driver uses DRM_BRIDGE_ATTACH_NO_CONNECTOR,
tc358767 will behave properly and skip the creation of the connector.

However, tc_get_display_props(), which is used to find out about the DP
monitor and link, is only called from two places: .atomic_enable() and
tc_connector_get_modes(). The latter is only used when tc358767 creates
its own connector, i.e. when DRM_BRIDGE_ATTACH_NO_CONNECTOR is _not_
set.

Thus, the driver never finds out the link properties before get_edid()
is called. With num_lanes of 0 and link_rate of 0 there are not many
valid modes...

Fix this by adding tc_connector_get_modes() call at the beginning of
get_edid(), so that we have up to date information before looking at the
modes.

Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
Closes: https://lore.kernel.org/all/24282420-b4dd-45b3-bb1c-fc37fe4a8205@siemens.com/
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/gpu/drm/bridge/tc358767.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
index 0affcefdeb1c..137a9f5e3cad 100644
--- a/drivers/gpu/drm/bridge/tc358767.c
+++ b/drivers/gpu/drm/bridge/tc358767.c
@@ -1579,6 +1579,13 @@ static struct edid *tc_get_edid(struct drm_bridge *bridge,
 				struct drm_connector *connector)
 {
 	struct tc_data *tc = bridge_to_tc(bridge);
+	int ret;
+
+	ret = tc_get_display_props(tc);
+	if (ret < 0) {
+		dev_err(tc->dev, "failed to read display props: %d\n", ret);
+		return 0;
+	}
 
 	return drm_get_edid(connector, &tc->aux.ddc);
 }

-- 
2.34.1

Re: [PATCH 2/2] drm/bridge: tc358767: Fix link properties discovery

[Aradhya Bhatia]

On 31-Oct-23 18:56, Tomi Valkeinen wrote:
> When a display controller driver uses DRM_BRIDGE_ATTACH_NO_CONNECTOR,
> tc358767 will behave properly and skip the creation of the connector.
> 
> However, tc_get_display_props(), which is used to find out about the DP
> monitor and link, is only called from two places: .atomic_enable() and
> tc_connector_get_modes(). The latter is only used when tc358767 creates
> its own connector, i.e. when DRM_BRIDGE_ATTACH_NO_CONNECTOR is _not_
> set.
> 
> Thus, the driver never finds out the link properties before get_edid()
> is called. With num_lanes of 0 and link_rate of 0 there are not many
> valid modes...
> 
> Fix this by adding tc_connector_get_modes() call at the beginning of
> get_edid(), so that we have up to date information before looking at the
> modes.
> 
> Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
> Closes: https://lore.kernel.org/all/24282420-b4dd-45b3-bb1c-fc37fe4a8205@siemens.com/
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> ---

Thank you, Tomi, for quickly debugging this!

Reviewed-by: Aradhya Bhatia <a-bhatia1@ti.com>

Regards
Aradhya

>  drivers/gpu/drm/bridge/tc358767.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
> index 0affcefdeb1c..137a9f5e3cad 100644
> --- a/drivers/gpu/drm/bridge/tc358767.c
> +++ b/drivers/gpu/drm/bridge/tc358767.c
> @@ -1579,6 +1579,13 @@ static struct edid *tc_get_edid(struct drm_bridge *bridge,
>  				struct drm_connector *connector)
>  {
>  	struct tc_data *tc = bridge_to_tc(bridge);
> +	int ret;
> +
> +	ret = tc_get_display_props(tc);
> +	if (ret < 0) {
> +		dev_err(tc->dev, "failed to read display props: %d\n", ret);
> +		return 0;
> +	}
>  
>  	return drm_get_edid(connector, &tc->aux.ddc);
>  }
> 

Re: [PATCH 0/2] drm/bridge: tc358767: Fix DRM_BRIDGE_ATTACH_NO_CONNECTOR case

[Jan Kiszka]

On 31.10.23 14:26, Tomi Valkeinen wrote:
> These two patches are needed to make tc358767 work in the
> DRM_BRIDGE_ATTACH_NO_CONNECTOR case, at least when using a DP connector.
> The first patch, "drm/bridge: tc358767: Support input format negotiation
> hook" was already sent separately, but I included it here for
> completeness, as both are needed to get a working display.
> 
> I have tested this with TI AM654 EVM with a tc358767 add-on card.
> 
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> ---
> Aradhya Bhatia (1):
>       drm/bridge: tc358767: Support input format negotiation hook
> 
> Tomi Valkeinen (1):
>       drm/bridge: tc358767: Fix link properties discovery
> 
>  drivers/gpu/drm/bridge/tc358767.c | 32 ++++++++++++++++++++++++++++++++
>  1 file changed, 32 insertions(+)
> ---
> base-commit: 79d94360d50fcd487edcfe118a47a2881534923f
> change-id: 20231031-tc358767-58e3ebdf95f0
> 
> Best regards,

Tested-by: Jan Kiszka <jan.kiszka@siemens.com>

Would be good to have that in stable for 6.6 as well then.

Thanks,
Jan

-- 
Siemens AG, Technology
Linux Expert Center

Re: [PATCH 0/2] drm/bridge: tc358767: Fix DRM_BRIDGE_ATTACH_NO_CONNECTOR case

[Jan Kiszka]

On 31.10.23 14:26, Tomi Valkeinen wrote:
> These two patches are needed to make tc358767 work in the
> DRM_BRIDGE_ATTACH_NO_CONNECTOR case, at least when using a DP connector.
> The first patch, "drm/bridge: tc358767: Support input format negotiation
> hook" was already sent separately, but I included it here for
> completeness, as both are needed to get a working display.
> 
> I have tested this with TI AM654 EVM with a tc358767 add-on card.
> 
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> ---
> Aradhya Bhatia (1):
>       drm/bridge: tc358767: Support input format negotiation hook
> 
> Tomi Valkeinen (1):
>       drm/bridge: tc358767: Fix link properties discovery
> 
>  drivers/gpu/drm/bridge/tc358767.c | 32 ++++++++++++++++++++++++++++++++
>  1 file changed, 32 insertions(+)
> ---
> base-commit: 79d94360d50fcd487edcfe118a47a2881534923f
> change-id: 20231031-tc358767-58e3ebdf95f0
> 
> Best regards,

What's the plan for these fixes? I'm not yet seeing them in Linus' tree,
thus also not in stable.

Jan

-- 
Siemens AG, Technology
Linux Expert Center

Re: [PATCH 0/2] drm/bridge: tc358767: Fix DRM_BRIDGE_ATTACH_NO_CONNECTOR case

[Tomi Valkeinen]

On 15/12/2023 15:33, Jan Kiszka wrote:
> On 31.10.23 14:26, Tomi Valkeinen wrote:
>> These two patches are needed to make tc358767 work in the
>> DRM_BRIDGE_ATTACH_NO_CONNECTOR case, at least when using a DP connector.
>> The first patch, "drm/bridge: tc358767: Support input format negotiation
>> hook" was already sent separately, but I included it here for
>> completeness, as both are needed to get a working display.
>>
>> I have tested this with TI AM654 EVM with a tc358767 add-on card.
>>
>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
>> ---
>> Aradhya Bhatia (1):
>>        drm/bridge: tc358767: Support input format negotiation hook
>>
>> Tomi Valkeinen (1):
>>        drm/bridge: tc358767: Fix link properties discovery
>>
>>   drivers/gpu/drm/bridge/tc358767.c | 32 ++++++++++++++++++++++++++++++++
>>   1 file changed, 32 insertions(+)
>> ---
>> base-commit: 79d94360d50fcd487edcfe118a47a2881534923f
>> change-id: 20231031-tc358767-58e3ebdf95f0
>>
>> Best regards,
> 
> What's the plan for these fixes? I'm not yet seeing them in Linus' tree,
> thus also not in stable.
> 
> Jan
> 

The discussion continued in v2 of the series. There are some open 
question in the tc358767 behavior.

  Tomi