Re: [PATCH 15/17] drm/i915/dp: Add helpers for joiner candidate loops

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

On Fri, Jan 30, 2026 at 01:48:10PM +0530, Ankit Nautiyal wrote:
> Introduce for_each_joiner_candidate(), intel_dp_joiner_candidate_valid()
> and intel_dp_joiner_candidate_valid() to remove duplicated joiner
> enumeration and validity checks across DP SST and MST paths.
> 
> Suggested-by: Imre Deak <imre.deak@intel.com>
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>

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

> ---
>  drivers/gpu/drm/i915/display/intel_dp.c     | 44 ++++++++++-----------
>  drivers/gpu/drm/i915/display/intel_dp.h     |  7 ++++
>  drivers/gpu/drm/i915/display/intel_dp_mst.c | 25 +-----------
>  3 files changed, 29 insertions(+), 47 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 3905723f5ab6..920e4d593b1d 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -1492,19 +1492,9 @@ intel_dp_mode_valid(struct drm_connector *_connector,
>  	 * over candidate pipe counts and evaluate each combination.
>  	 */
>  	status = MODE_CLOCK_HIGH;
> -	for (num_joined_pipes = 1; num_joined_pipes <= I915_MAX_PIPES; num_joined_pipes++) {
> +	for_each_joiner_candidate(connector, mode, num_joined_pipes) {
>  		int dsc_slice_count = 0;
>  
> -		if (connector->force_joined_pipes &&
> -		    num_joined_pipes != connector->force_joined_pipes)
> -			continue;
> -
> -		if (!intel_dp_can_join(display, num_joined_pipes))
> -			continue;
> -
> -		if (mode->hdisplay > num_joined_pipes * intel_dp_max_hdisplay_per_pipe(display))
> -			continue;
> -
>  		status = intel_pfit_mode_valid(display, mode, output_format, num_joined_pipes);
>  		if (status != MODE_OK)
>  			continue;
> @@ -2884,7 +2874,6 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
>  			     struct drm_connector_state *conn_state,
>  			     bool respect_downstream_limits)
>  {
> -	struct intel_display *display = to_intel_display(encoder);
>  	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
>  	struct intel_connector *connector =
>  		to_intel_connector(conn_state->connector);
> @@ -2898,18 +2887,7 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
>  	    !intel_dp_supports_fec(intel_dp, connector, crtc_state))
>  		return -EINVAL;
>  
> -	for (num_joined_pipes = 1; num_joined_pipes <= I915_MAX_PIPES; num_joined_pipes++) {
> -		if (connector->force_joined_pipes &&
> -		    num_joined_pipes != connector->force_joined_pipes)
> -			continue;
> -
> -		if (!intel_dp_can_join(display, num_joined_pipes))
> -			continue;
> -
> -		if (adjusted_mode->hdisplay >
> -		    num_joined_pipes * intel_dp_max_hdisplay_per_pipe(display))
> -			continue;
> -
> +	for_each_joiner_candidate(connector, adjusted_mode, num_joined_pipes) {
>  		/*
>  		 * NOTE:
>  		 * The crtc_state->joiner_pipes should have been set at the end
> @@ -7219,3 +7197,21 @@ 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,
> +				     int hdisplay,
> +				     int num_joined_pipes)
> +{
> +	struct intel_display *display = to_intel_display(connector);
> +
> +	if (!intel_dp_can_join(display, num_joined_pipes))
> +		return false;
> +
> +	if (hdisplay > num_joined_pipes * intel_dp_max_hdisplay_per_pipe(display))
> +		return false;
> +
> +	if (connector->force_joined_pipes && connector->force_joined_pipes != num_joined_pipes)
> +		return false;
> +
> +	return true;
> +}
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h
> index 95a38763a367..ff527b351de0 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.h
> +++ b/drivers/gpu/drm/i915/display/intel_dp.h
> @@ -229,5 +229,12 @@ 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,
> +				     int hdisplay,
> +				     int num_joined_pipes);
> +
> +#define for_each_joiner_candidate(__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))
>  
>  #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 ad66c483959b..2c8a7c57e795 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -720,18 +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 (num_joined_pipes = 1; num_joined_pipes <= I915_MAX_PIPES; num_joined_pipes++) {
> -		if (connector->force_joined_pipes &&
> -		    num_joined_pipes != connector->force_joined_pipes)
> -			continue;
> -
> -		if (!intel_dp_can_join(display, num_joined_pipes))
> -			continue;
> -
> -		if (adjusted_mode->hdisplay >
> -		    num_joined_pipes * intel_dp_max_hdisplay_per_pipe(display))
> -			continue;
> -
> +	for_each_joiner_candidate(connector, adjusted_mode, num_joined_pipes) {
>  		if (num_joined_pipes > 1)
>  			pipe_config->joiner_pipes = GENMASK(crtc->pipe + num_joined_pipes - 1,
>  							    crtc->pipe);
> @@ -1535,19 +1524,9 @@ mst_connector_mode_valid_ctx(struct drm_connector *_connector,
>  	}
>  
>  	*status = MODE_CLOCK_HIGH;
> -	for (num_joined_pipes = 1; num_joined_pipes <= I915_MAX_PIPES; num_joined_pipes++) {
> +	for_each_joiner_candidate(connector, mode, num_joined_pipes) {
>  		int dsc_slice_count = 0;
>  
> -		if (connector->force_joined_pipes &&
> -		    num_joined_pipes != connector->force_joined_pipes)
> -			continue;
> -
> -		if (!intel_dp_can_join(display, num_joined_pipes))
> -			continue;
> -
> -		if (mode->hdisplay > num_joined_pipes * intel_dp_max_hdisplay_per_pipe(display))
> -			continue;
> -
>  		if (intel_dp_has_dsc(connector) &&
>  		    drm_dp_sink_supports_fec(connector->dp.fec_capability)) {
>  			/*
> -- 
> 2.45.2
>