Re: [PATCH 3/4] drm/i915/dp_mst: Track min link BPP as x16 fixed-point during mode validation

["Nautiyal, Ankit K" <ankit.k.nautiyal@intel.com>]

On 2/16/2026 12:34 PM, Imre Deak wrote:
> Track the minimum link BPP as an x16 fixed-point value and, for
> clarity, rename the variable storing it to min_link_bpp_x16.
>
> Signed-off-by: Imre Deak <imre.deak@intel.com>

Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>


> ---
>   drivers/gpu/drm/i915/display/intel_dp_mst.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> index 29713075e4135..7ca2e2245fc70 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -1463,10 +1463,10 @@ mst_connector_mode_valid_ctx(struct drm_connector *_connector,
>   	struct intel_dp *intel_dp = connector->mst.dp;
>   	struct drm_dp_mst_topology_mgr *mgr = &intel_dp->mst.mgr;
>   	struct drm_dp_mst_port *port = connector->mst.port;
> -	const int min_bpp = 18;
>   	int max_rate, mode_rate, max_lanes, max_link_clock;
>   	unsigned long bw_overhead_flags =
>   		DRM_DP_BW_OVERHEAD_MST | DRM_DP_BW_OVERHEAD_SSC_REF_CLK;
> +	int min_link_bpp_x16 = fxp_q4_from_int(18);
>   	int ret;
>   	bool dsc = false;
>   	int target_clock = mode->clock;
> @@ -1498,7 +1498,7 @@ mst_connector_mode_valid_ctx(struct drm_connector *_connector,
>   					       max_link_clock, max_lanes);
>   	mode_rate = intel_dp_link_required(max_link_clock, max_lanes,
>   					   mode->clock, mode->hdisplay,
> -					   fxp_q4_from_int(min_bpp),
> +					   min_link_bpp_x16,
>   					   bw_overhead_flags);
>   
>   	/*
> @@ -1518,7 +1518,7 @@ mst_connector_mode_valid_ctx(struct drm_connector *_connector,
>   		return ret;
>   
>   	if (mode_rate > max_rate ||
> -	    drm_dp_calc_pbn_mode(mode->clock, min_bpp << 4) > port->full_pbn) {
> +	    drm_dp_calc_pbn_mode(mode->clock, min_link_bpp_x16) > port->full_pbn) {
>   		*status = MODE_CLOCK_HIGH;
>   		return 0;
>   	}