Re: [PATCH] drm/i915/display: Allow forcing the joiner on eDP

["Hogander, Jouni" <jouni.hogander@intel.com>]

On Wed, 2026-09-23 at 11:59 +0000, Mika Kahola wrote:
> intel_dp_has_joiner() rejects eDP unless the VBT enables the pipe
> joiner, and the debugfs file is only created when that returns true,
> so
> i915_joiner_force_enable can never turn it on.
> 
> Always create the file for DP and eDP, and let a forced pipe count
> above one override the VBT.
> 
> Assisted-by: Copilot:claude-opus-5
> Signed-off-by: Mika Kahola <mika.kahola@intel.com>

Reviewed-by: Jouni Högander <jouni.hogander@intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_display_debugfs.c |  5 ++---
>  drivers/gpu/drm/i915/display/intel_dp.c              | 12 +++++++++-
> --
>  2 files changed, 11 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> index 3e302f23f247..e55fa01addb5 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> @@ -1352,9 +1352,8 @@ void intel_connector_debugfs_add(struct
> intel_connector *connector)
>  				    connector,
> &i915_dsc_fractional_bpp_fops);
>  	}
>  
> -	if ((connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
> -	     connector_type == DRM_MODE_CONNECTOR_eDP) &&
> -	    intel_dp_has_joiner(intel_attached_dp(connector))) {
> +	if (connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
> +	    connector_type == DRM_MODE_CONNECTOR_eDP) {
>  		debugfs_create_file("i915_joiner_force_enable",
> 0644, root,
>  				    connector, &i915_joiner_fops);
>  	}
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index 2480b8ce3bec..80ce71ce4c20 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -473,9 +473,15 @@ bool intel_dp_has_joiner(struct intel_dp
> *intel_dp)
>  	if (intel_dp->mso_link_count)
>  		return false;
>  
> -	if (intel_dp_is_edp(intel_dp) &&
> -	    !connector->panel.vbt.edp.pipe_joiner_enable)
> -		return false;
> +	if (intel_dp_is_edp(intel_dp)) {
> +		bool pipe_joiner_enable = connector-
> >panel.vbt.edp.pipe_joiner_enable;
> +
> +		if (connector->force_joined_pipes > 1)
> +			pipe_joiner_enable = true;
> +
> +		if (!pipe_joiner_enable)
> +			return false;
> +	}
>  
>  	return DISPLAY_VER(display) >= 12 ||
>  		(DISPLAY_VER(display) == 11 &&