On Thu, Feb 05, 2026 at 02:06:23PM +0530, Ankit Nautiyal wrote:
> Commit ad121a62d566 ("drm/i915/dp: Rework pipe joiner logic in mode_valid")
> replaced intel_dp_num_joined_pipes() with an explicit joiner candidate
> iteration. The previous code implicitly checked for DP joiner capability
> via intel_dp_has_joiner(), but this check was lost during the refactor.
>
> Restore the missing intel_dp_has_joiner() check in intel_dp_can_join() so
> that DP specific joiner conditions are taken into account.
>
> This change also requires propagating struct intel_dp * from the callers
> down to the new check.
>
> Fixes: ad121a62d566 ("drm/i915/dp: Rework pipe joiner logic in mode_valid")
> Cc: Ankit Nautiyal <[email protected]>
> Cc: Imre Deak <[email protected]>
> Signed-off-by: Ankit Nautiyal <[email protected]>
> ---
> drivers/gpu/drm/i915/display/intel_dp.c | 16 +++++++++++-----
> drivers/gpu/drm/i915/display/intel_dp.h | 7 ++++---
> drivers/gpu/drm/i915/display/intel_dp_mst.c | 4 ++--
> 3 files changed, 17 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index 4f5b89f80e55..3021c64d0f85 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -1397,9 +1397,14 @@ bool intel_dp_has_dsc(const struct intel_connector
> *connector)
> }
>
> static
> -bool intel_dp_can_join(struct intel_display *display,
> +bool intel_dp_can_join(struct intel_dp *intel_dp,
> int num_joined_pipes)
> {
> + struct intel_display *display = to_intel_display(intel_dp);
> +
> + if (num_joined_pipes > 1 && !intel_dp_has_joiner(intel_dp))
> + return false;
> +
> switch (num_joined_pipes) {
> case 1:
> return true;
> @@ -1496,7 +1501,7 @@ intel_dp_mode_valid(struct drm_connector *_connector,
> * over candidate pipe counts and evaluate each combination.
> */
> status = MODE_CLOCK_HIGH;
> - for_each_joiner_candidate(connector, mode, num_joined_pipes) {
> + for_each_joiner_candidate(intel_dp, connector, mode, num_joined_pipes) {
> int dsc_slice_count = 0;
>
> status = intel_pfit_mode_valid(display, mode, output_format,
> num_joined_pipes);
> @@ -2895,7 +2900,7 @@ intel_dp_compute_link_config(struct intel_encoder
> *encoder,
> !intel_dp_supports_fec(intel_dp, connector, crtc_state))
> return -EINVAL;
>
> - for_each_joiner_candidate(connector, adjusted_mode, num_joined_pipes) {
> + for_each_joiner_candidate(intel_dp, connector, adjusted_mode,
> num_joined_pipes) {
> /*
> * NOTE:
> * The crtc_state->joiner_pipes should have been set at the end
> @@ -7213,13 +7218,14 @@ int intel_dp_sdp_min_guardband(const struct
> intel_crtc_state *crtc_state,
> return sdp_guardband;
> }
>
> -bool intel_dp_joiner_candidate_valid(struct intel_connector *connector,
> +bool intel_dp_joiner_candidate_valid(struct intel_dp *intel_dp,
> + struct intel_connector *connector,
> int hdisplay,
> int num_joined_pipes)
intel_dp can be always deducted from the connector, via
intel_attached_dp(), so no need to pass intel_dp separately.
> {
> struct intel_display *display = to_intel_display(connector);
>
> - if (!intel_dp_can_join(display, num_joined_pipes))
> + if (!intel_dp_can_join(intel_dp, num_joined_pipes))
> return false;
>
> if (hdisplay > num_joined_pipes *
> intel_dp_max_hdisplay_per_pipe(display))
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.h
> b/drivers/gpu/drm/i915/display/intel_dp.h
> index cbd7fcd3789f..37302ebe1cf9 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.h
> +++ b/drivers/gpu/drm/i915/display/intel_dp.h
> @@ -227,12 +227,13 @@ bool intel_dp_dotclk_valid(struct intel_display
> *display,
> int htotal,
> int dsc_slice_count,
> int num_joined_pipes);
> -bool intel_dp_joiner_candidate_valid(struct intel_connector *connector,
> +bool intel_dp_joiner_candidate_valid(struct intel_dp *intel_dp,
> + struct intel_connector *connector,
> int hdisplay,
> int num_joined_pipes);
>
> -#define for_each_joiner_candidate(__connector, __mode, __num_joined_pipes) \
> +#define for_each_joiner_candidate(__intel_dp, __connector, __mode,
> __num_joined_pipes) \
> for ((__num_joined_pipes) = 1; (__num_joined_pipes) <=
> (I915_MAX_PIPES); (__num_joined_pipes)++) \
> - for_each_if(intel_dp_joiner_candidate_valid(__connector,
> (__mode)->hdisplay, __num_joined_pipes))
> + for_each_if(intel_dp_joiner_candidate_valid(__intel_dp,
> __connector, (__mode)->hdisplay, __num_joined_pipes))
>
> #endif /* __INTEL_DP_H__ */
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> index 29713075e413..b2d3f35edd78 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -720,7 +720,7 @@ static int mst_stream_compute_config(struct intel_encoder
> *encoder,
> pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB;
> pipe_config->has_pch_encoder = false;
>
> - for_each_joiner_candidate(connector, adjusted_mode, num_joined_pipes) {
> + for_each_joiner_candidate(intel_dp, connector, adjusted_mode,
> num_joined_pipes) {
> if (num_joined_pipes > 1)
> pipe_config->joiner_pipes = GENMASK(crtc->pipe +
> num_joined_pipes - 1,
> crtc->pipe);
> @@ -1524,7 +1524,7 @@ mst_connector_mode_valid_ctx(struct drm_connector
> *_connector,
> }
>
> *status = MODE_CLOCK_HIGH;
> - for_each_joiner_candidate(connector, mode, num_joined_pipes) {
> + for_each_joiner_candidate(intel_dp, connector, mode, num_joined_pipes) {
> int dsc_slice_count = 0;
>
> if (intel_dp_has_dsc(connector) &&
> --
> 2.45.2
>
