Re: [PATCH 29/32] drm/i915/display: Handle dedicated external ports in intel_encoder_is_tc()

[Jani Nikula <jani.nikula@linux.intel.com>]

On Wed, 15 Oct 2025, Gustavo Sousa <gustavo.sousa@intel.com> wrote:
> Starting with Xe3p_LPD, the VBT has a new field, called in the driver
> "dedicated_external", which tells that a Type-C capable port is
> physically connected to a PHY outside of the Type-C subsystem.  When
> that's the case, the driver must not do the extra Type-C programming for
> that port.  Update intel_encoder_is_tc() to check for that case.
>
> While at it, add a note to intel_phy_is_tc() to remind us that it is
> about whether the respective port is a Type-C capable port rather than
> the PHY itself.
>
> (Maybe it would be a nice idea to rename intel_phy_is_tc()?)
>
> Note that this was handled with a new bool member added to struct
> intel_digital_port instead of having querying the VBT directly because
> VBT memory is freed (intel_bios_driver_remove) before encoder cleanup
> (intel_ddi_encoder_destroy), which would cause an oops to happen when
> the latter calls intel_encoder_is_tc().  This could be fixed by keeping
> VBT data around longer, but that's left for a follow-up work, if deemed
> necessary.
>
> Cc: Shekhar Chauhan <shekhar.chauhan@intel.com>
> Signed-off-by: Gustavo Sousa <gustavo.sousa@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_ddi.c           |  7 +++++++
>  drivers/gpu/drm/i915/display/intel_display.c       | 19 ++++++++++++++++++-
>  drivers/gpu/drm/i915/display/intel_display_types.h |  1 +
>  3 files changed, 26 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index c09aa759f4d4..6fcbebb81263 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -5343,6 +5343,13 @@ void intel_ddi_init(struct intel_display *display,
>  			goto err;
>  	}
>  
> +	if (intel_bios_encoder_is_dedicated_external(devdata)) {
> +		dig_port->dedicated_external = true;
> +		drm_dbg_kms(display->drm,
> +			    "Port %c is dedicated external\n",
> +			    port_name(port));
> +	}

With the information print added in parse_ddi_port(), the printing here
becomes redundant.

> +
>  	if (intel_encoder_is_tc(encoder)) {
>  		bool is_legacy =
>  			!intel_bios_encoder_supports_typec_usb(devdata) &&
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 6ac718192e1c..46474199d1ab 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -1778,7 +1778,17 @@ bool intel_phy_is_combo(struct intel_display *display, enum phy phy)
>  		return false;
>  }
>  
> -/* Prefer intel_encoder_is_tc() */
> +/*
> + * This function returns true if the DDI port respective to the PHY enumeration
> + * is a Type-C capable port.
> + *
> + * Depending on the VBT, the port might be configured
> + * as a "dedicated external" port, meaning that actual physical PHY is outside
> + * of the Type-C subsystem and, as such, not really a "Type-C PHY".
> + *
> + * Prefer intel_encoder_is_tc(), especially if you really need to know if we
> + * are dealing with Type-C connections.
> + */
>  bool intel_phy_is_tc(struct intel_display *display, enum phy phy)
>  {
>  	/*
> @@ -1863,6 +1873,13 @@ bool intel_encoder_is_tc(struct intel_encoder *encoder)
>  {
>  	struct intel_display *display = to_intel_display(encoder);
>  
> +	if (intel_encoder_is_dig_port(encoder)) {
> +		struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
> +
> +		if (dig_port->dedicated_external)

Why go through all the trouble of duplicating the "decicated external"
information in the digital port, when you already have encoder
available, and can just use intel_bios_encoder_is_dedicated_external()
right here?

> +			return false;
> +	}
> +
>  	return intel_phy_is_tc(display, intel_encoder_to_phy(encoder));
>  }
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 13652e2996a4..b5b9351501b1 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1909,6 +1909,7 @@ struct intel_digital_port {
>  	bool lane_reversal;
>  	bool ddi_a_4_lanes;
>  	bool release_cl2_override;
> +	bool dedicated_external;
>  	u8 max_lanes;
>  	/* Used for DP and ICL+ TypeC/DP and TypeC/HDMI ports. */
>  	enum aux_ch aux_ch;

-- 
Jani Nikula, Intel