Re: [PATCH v4 02/11] drm/i915/vbt: Add fields dedicated_external and dyn_port_over_tc

[Imre Deak <imre.deak@intel.com>]

On Fri, Nov 07, 2025 at 09:05:35PM -0300, Gustavo Sousa wrote:
> VBT version 264 adds new fields associated to Xe3p_LPD's new ways of
> configuring SoC for TC ports and PHYs.  Update the code to match the
> updates in VBT.
> 
> The new field dedicated_external is used to represent TC ports that are
> connected to PHYs outside of the Type-C subsystem, meaning that they
> behave like dedicated ports and don't require the extra Type-C
> programming.  In an upcoming change, we will update the driver to take
> this field into consideration when detecting the type of port.
> 
> The new field dyn_port_over_tc is used to inform that the TC port can be
> dynamically allocated for a legacy connector in the Type-C subsystem,
> which is a new feature in Xe3p_LPD.  In upcoming changes, we will use
> that field in order to handle the IOM resource management programming
> required for that.
> 
> Note that, when dedicated_external is set, the fields dp_usb_type_c and
> tbt are tagged as "don't care" in the spec, so they should be ignored in
> that case, so also add a sanitization function to take care of forcing
> them to zero when dedicated_external is true.
> 
> v2:
>   - Use sanitization function to force dp_usb_type_c and tbt fields to
>     be zero instead of adding a
>     intel_bios_encoder_is_dedicated_external() check in each of their
>     respective accessor functions. (Jani)
>   - Print info about dedicated external ports in print_ddi_port().
>     (Jani)
> 
> Bspec: 20124, 68954, 74304
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Shekhar Chauhan <shekhar.chauhan@intel.com>
> Signed-off-by: Gustavo Sousa <gustavo.sousa@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_bios.c     | 54 ++++++++++++++++++++++++++-
>  drivers/gpu/drm/i915/display/intel_bios.h     |  2 +
>  drivers/gpu/drm/i915/display/intel_vbt_defs.h |  3 +-
>  3 files changed, 56 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
> index 852e4d6db8a3..1487d5e5a69d 100644
> --- a/drivers/gpu/drm/i915/display/intel_bios.c
> +++ b/drivers/gpu/drm/i915/display/intel_bios.c
> @@ -2530,6 +2530,36 @@ intel_bios_encoder_reject_edp_rate(const struct intel_bios_encoder_data *devdata
>  	return devdata->child.edp_data_rate_override & edp_rate_override_mask(rate);
>  }
>  
> +static void sanitize_dedicated_external(struct intel_bios_encoder_data *devdata,
> +					enum port port)
> +{
> +	struct intel_display *display = devdata->display;
> +
> +	if (!intel_bios_encoder_is_dedicated_external(devdata))
> +		return;
> +
> +	/*
> +	 * Fields dp_usb_type_c and tbt must be ignored when
> +	 * dedicated_external is set.  Since dedicated_external is for
> +	 * ports connected to PHYs outside of the Type-C subsystem, it
> +	 * is safe to force those fields to zero.
> +	 */
> +
> +	if (devdata->child.dp_usb_type_c) {
> +		drm_dbg_kms(display->drm,
> +			    "VBT claims Port %c supports USB Type-C, but the port is dedicated external, ignoring\n",
> +			    port_name(port));
> +		devdata->child.dp_usb_type_c = 0;
> +	}
> +
> +	if (devdata->child.tbt) {
> +		drm_dbg_kms(display->drm,
> +			    "VBT claims Port %c supports TBT, but the port is dedicated external, ignoring\n",
> +			    port_name(port));
> +		devdata->child.tbt = 0;
> +	}
> +}
> +
>  static void sanitize_device_type(struct intel_bios_encoder_data *devdata,
>  				 enum port port)
>  {
> @@ -2668,7 +2698,8 @@ static void print_ddi_port(const struct intel_bios_encoder_data *devdata)
>  {
>  	struct intel_display *display = devdata->display;
>  	const struct child_device_config *child = &devdata->child;
> -	bool is_dvi, is_hdmi, is_dp, is_edp, is_dsi, is_crt, supports_typec_usb, supports_tbt;
> +	bool is_dvi, is_hdmi, is_dp, is_edp, is_dsi, is_crt, supports_typec_usb,
> +		supports_tbt, dedicated_external;
>  	int dp_boost_level, dp_max_link_rate, hdmi_boost_level, hdmi_level_shift, max_tmds_clock;
>  	enum port port;
>  
> @@ -2694,6 +2725,12 @@ static void print_ddi_port(const struct intel_bios_encoder_data *devdata)
>  		    supports_typec_usb, supports_tbt,
>  		    devdata->dsc != NULL);
>  
> +	dedicated_external = intel_bios_encoder_is_dedicated_external(devdata);
> +	if (dedicated_external)

Nit: the variable could be dropped imo, and would be good to print the
dyn_port_over_tc info as well. Either way:

Reviewed-by: Imre Deak <imre.deak@intel.com>

> +		drm_dbg_kms(display->drm,
> +			    "Port %c is dedicated external\n",
> +			    port_name(port));
> +
>  	hdmi_level_shift = intel_bios_hdmi_level_shift(devdata);
>  	if (hdmi_level_shift >= 0) {
>  		drm_dbg_kms(display->drm,
> @@ -2751,6 +2788,7 @@ static void parse_ddi_port(struct intel_bios_encoder_data *devdata)
>  		return;
>  	}
>  
> +	sanitize_dedicated_external(devdata, port);
>  	sanitize_device_type(devdata, port);
>  	sanitize_hdmi_level_shift(devdata, port);
>  }
> @@ -2778,7 +2816,7 @@ static int child_device_expected_size(u16 version)
>  {
>  	BUILD_BUG_ON(sizeof(struct child_device_config) < 40);
>  
> -	if (version > 263)
> +	if (version > 264)
>  		return -ENOENT;
>  	else if (version >= 263)
>  		return 44;
> @@ -3723,6 +3761,18 @@ bool intel_bios_encoder_supports_tbt(const struct intel_bios_encoder_data *devda
>  	return devdata->display->vbt.version >= 209 && devdata->child.tbt;
>  }
>  
> +bool intel_bios_encoder_is_dedicated_external(const struct intel_bios_encoder_data *devdata)
> +{
> +	return devdata->display->vbt.version >= 264 &&
> +		devdata->child.dedicated_external;
> +}
> +
> +bool intel_bios_encoder_supports_dyn_port_over_tc(const struct intel_bios_encoder_data *devdata)
> +{
> +	return devdata->display->vbt.version >= 264 &&
> +		devdata->child.dyn_port_over_tc;
> +}
> +
>  bool intel_bios_encoder_lane_reversal(const struct intel_bios_encoder_data *devdata)
>  {
>  	return devdata && devdata->child.lane_reversal;
> diff --git a/drivers/gpu/drm/i915/display/intel_bios.h b/drivers/gpu/drm/i915/display/intel_bios.h
> index f9e438b2787b..75dff27b4228 100644
> --- a/drivers/gpu/drm/i915/display/intel_bios.h
> +++ b/drivers/gpu/drm/i915/display/intel_bios.h
> @@ -79,6 +79,8 @@ bool intel_bios_encoder_supports_dp(const struct intel_bios_encoder_data *devdat
>  bool intel_bios_encoder_supports_edp(const struct intel_bios_encoder_data *devdata);
>  bool intel_bios_encoder_supports_typec_usb(const struct intel_bios_encoder_data *devdata);
>  bool intel_bios_encoder_supports_tbt(const struct intel_bios_encoder_data *devdata);
> +bool intel_bios_encoder_is_dedicated_external(const struct intel_bios_encoder_data *devdata);
> +bool intel_bios_encoder_supports_dyn_port_over_tc(const struct intel_bios_encoder_data *devdata);
>  bool intel_bios_encoder_supports_dsi(const struct intel_bios_encoder_data *devdata);
>  bool intel_bios_encoder_supports_dp_dual_mode(const struct intel_bios_encoder_data *devdata);
>  bool intel_bios_encoder_is_lspcon(const struct intel_bios_encoder_data *devdata);
> diff --git a/drivers/gpu/drm/i915/display/intel_vbt_defs.h b/drivers/gpu/drm/i915/display/intel_vbt_defs.h
> index 70e31520c560..57fda5824c9c 100644
> --- a/drivers/gpu/drm/i915/display/intel_vbt_defs.h
> +++ b/drivers/gpu/drm/i915/display/intel_vbt_defs.h
> @@ -554,7 +554,8 @@ struct child_device_config {
>  	u8 dvo_function;
>  	u8 dp_usb_type_c:1;					/* 195+ */
>  	u8 tbt:1;						/* 209+ */
> -	u8 flags2_reserved:2;					/* 195+ */
> +	u8 dedicated_external:1;				/* 264+ */
> +	u8 dyn_port_over_tc:1;					/* 264+ */
>  	u8 dp_port_trace_length:4;				/* 209+ */
>  	u8 dp_gpio_index;					/* 195+ */
>  	u16 dp_gpio_pin_num;					/* 195+ */
> 
> -- 
> 2.51.0
>