Re: [PATCH 4/4] drm/i915/debugfs: Reject invalid force_joined_pipes harder

On 8/7/2026 6:04 PM, Jani Nikula wrote:
> Reject invalid joiner forcing more thoroughly, taking into account
> whether bigjoiner or uncompressed joiner is available, and whether the
> requested number of pipes can actually be joined.
>
> Cc: Ankit Nautiyal <[email protected]>
> Signed-off-by: Jani Nikula <[email protected]>

LGTM.

Reviewed-by: Ankit Nautiyal <[email protected]>


> ---
>   .../drm/i915/display/intel_display_debugfs.c  | 19 ++++---------------
>   1 file changed, 4 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> index 2bbf4760dc30..3e302f23f247 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> @@ -1285,22 +1285,11 @@ static ssize_t i915_joiner_write(struct file *file,
>   	if (ret < 0)
>   		return ret;
>   
> -	switch (force_joined_pipes) {
> -	case 0:
> -	case 1:
> -	case 2:
> -		connector->force_joined_pipes = force_joined_pipes;
> -		break;
> -	case 4:
> -		if (HAS_ULTRAJOINER(display)) {
> -			connector->force_joined_pipes = force_joined_pipes;
> -			break;
> -		}
> -
> -		fallthrough;
> -	default:
> +	if (force_joined_pipes &&
> +	    !intel_joiner_valid_primary_pipe_mask(display, force_joined_pipes))
>   		return -EINVAL;
> -	}
> +
> +	connector->force_joined_pipes = force_joined_pipes;
>   
>   	*offp += len;
>