On Wed, Oct 01, 2025 at 03:50:51PM -0700, Khaled Almahallawy wrote:
> Expose key Type-C port data in i915_display_info to make it easier to
> understand the port configuration and active mode, especially whether
> the link is in DP-Alt or TBT-Alt, without having to scan kernel logs.
>
> Tested in DP-Alt, TBT-Alt, SST, and MST.
>
> Expected output:
>
> [CONNECTOR:290:DP-2]: status: connected
> TC Port: E/TC#2 mode: tbt-alt pin assignment: - max lanes: 4
> physical dimensions: 600x340mm
> ...
> [CONNECTOR:263:DP-5]: status: connected
> TC Port: G/TC#4 mode: dp-alt pin assignment: C max lanes: 4
> physical dimensions: 610x350mm
>
> v2: Use drm_printer (Ville)
> Lock/Unlock around the printf (Imre)
> v3: Forward Declaration drm_printer struct (Jani)
>
> Cc: Ville Syrjälä <[email protected]>
> Cc: Imre Deak <[email protected]>
> Cc: Jani Nikula <[email protected]>
> Signed-off-by: Khaled Almahallawy <[email protected]>
> ---
> drivers/gpu/drm/i915/display/intel_display_debugfs.c | 5 +++++
> drivers/gpu/drm/i915/display/intel_tc.c | 12 ++++++++++++
> drivers/gpu/drm/i915/display/intel_tc.h | 3 +++
> 3 files changed, 20 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> index 10dddec3796f..5f5f1c50adfa 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> @@ -47,6 +47,7 @@
> #include "intel_psr_regs.h"
> #include "intel_vdsc.h"
> #include "intel_wm.h"
> +#include "intel_tc.h"
>
> static struct intel_display *node_to_intel_display(struct drm_info_node
> *node)
> {
> @@ -246,6 +247,7 @@ static void intel_connector_info(struct seq_file *m,
> {
> struct intel_connector *intel_connector = to_intel_connector(connector);
> const struct drm_display_mode *mode;
> + struct drm_printer p = drm_seq_file_printer(m);
>
> seq_printf(m, "[CONNECTOR:%d:%s]: status: %s\n",
> connector->base.id, connector->name,
> @@ -254,6 +256,9 @@ static void intel_connector_info(struct seq_file *m,
> if (connector->status == connector_status_disconnected)
> return;
>
> + if (intel_encoder_is_tc(intel_attached_encoder(intel_connector)))
> + intel_tc_info(&p, intel_attached_dig_port(intel_connector));
An MST connector doesn't have an attached encoder if it's not enabled,
so the above would lead to a NULL deref in that case.
Could you instead - in the connector_type switch below - get dig_port
via dp_to_dig_port(intel_attached_dp()) for DP and eDP and
hdmi_to_dig_port(intel_attached_hdmi()) for HDMI? You could print then
the TC info after the switch block if dig_port != NULL and
intel_encoder_is_tc(&dig_port->base).
> +
> seq_printf(m, "\tphysical dimensions: %dx%dmm\n",
> connector->display_info.width_mm,
> connector->display_info.height_mm);
> diff --git a/drivers/gpu/drm/i915/display/intel_tc.c
> b/drivers/gpu/drm/i915/display/intel_tc.c
> index c4a5601c5107..e666d25ea24a 100644
> --- a/drivers/gpu/drm/i915/display/intel_tc.c
> +++ b/drivers/gpu/drm/i915/display/intel_tc.c
> @@ -1703,6 +1703,18 @@ void intel_tc_port_sanitize_mode(struct
> intel_digital_port *dig_port,
> mutex_unlock(&tc->lock);
> }
>
> +void intel_tc_info(struct drm_printer *p, struct intel_digital_port
> *dig_port)
> +{
> + struct intel_tc_port *tc = to_tc_port(dig_port);
> +
> + mutex_lock(&tc->lock);
> + drm_printf(p, "\tTC Port: %s mode: %s pin assignment: %c max lanes:
> %d\n", tc->port_name,
> + tc_port_mode_name(tc->mode),
> + pin_assignment_name(tc->pin_assignment),
> + tc->max_lane_count);
> + mutex_unlock(&tc->lock);
> +}
> +
> /*
> * The type-C ports are different because even when they are connected, they
> may
> * not be available/usable by the graphics driver: see the comment on
> diff --git a/drivers/gpu/drm/i915/display/intel_tc.h
> b/drivers/gpu/drm/i915/display/intel_tc.h
> index fff8b96e4972..6719aea5bd58 100644
> --- a/drivers/gpu/drm/i915/display/intel_tc.h
> +++ b/drivers/gpu/drm/i915/display/intel_tc.h
> @@ -8,6 +8,7 @@
>
> #include <linux/types.h>
>
> +struct drm_printer;
> struct intel_crtc_state;
> struct intel_digital_port;
> struct intel_encoder;
> @@ -113,4 +114,6 @@ void intel_tc_port_cleanup(struct intel_digital_port
> *dig_port);
>
> bool intel_tc_cold_requires_aux_pw(struct intel_digital_port *dig_port);
>
> +void intel_tc_info(struct drm_printer *p, struct intel_digital_port
> *dig_port);
> +
> #endif /* __INTEL_TC_H__ */
> --
> 2.43.0
>
