[PATCH 07/14] drm/i915/dp: Add a separate function to reduce the link parameters

[Kandpal, Suraj]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Imre
> Deak
> Sent: Monday, July 22, 2024 10:25 PM
> To: intel-gfx at lists.freedesktop.org
> Subject: [PATCH 07/14] drm/i915/dp: Add a separate function to reduce the link
> parameters
> 
> A follow-up patch will add an alternative way to reduce the link parameters in
> BW order on MST links, prepare for that here.
> 
> Signed-off-by: Imre Deak <imre.deak at intel.com>

LGTM,
Reviewed-by: Suraj Kandpal <suraj.kandpal at intel.com>

> ---
>  .../drm/i915/display/intel_dp_link_training.c | 39 +++++++++++++++----
>  1 file changed, 31 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> index 58dea87a9fa28..57536ae200b77 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> @@ -1193,6 +1193,36 @@ static int reduce_lane_count(struct intel_dp
> *intel_dp, int current_lane_count)
>  	return current_lane_count >> 1;
>  }
> 
> +static bool reduce_link_params_in_rate_lane_order(struct intel_dp *intel_dp,
> +						  const struct intel_crtc_state
> *crtc_state,
> +						  int *new_link_rate, int
> *new_lane_count) {
> +	int link_rate;
> +	int lane_count;
> +
> +	lane_count = crtc_state->lane_count;
> +	link_rate = reduce_link_rate(intel_dp, crtc_state->port_clock);
> +	if (link_rate < 0) {
> +		lane_count = reduce_lane_count(intel_dp, crtc_state-
> >lane_count);
> +		link_rate = intel_dp_max_common_rate(intel_dp);
> +	}
> +
> +	if (lane_count < 0)
> +		return false;
> +
> +	*new_link_rate = link_rate;
> +	*new_lane_count = lane_count;
> +
> +	return true;
> +}
> +
> +static bool reduce_link_params(struct intel_dp *intel_dp, const struct
> intel_crtc_state *crtc_state,
> +			       int *new_link_rate, int *new_lane_count) {
> +	return reduce_link_params_in_rate_lane_order(intel_dp, crtc_state,
> +						     new_link_rate,
> new_lane_count); }
> +
>  static int intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp,
>  						   const struct intel_crtc_state
> *crtc_state)  { @@ -1206,14 +1236,7 @@ static int
> intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp,
>  		return 0;
>  	}
> 
> -	new_lane_count = crtc_state->lane_count;
> -	new_link_rate = reduce_link_rate(intel_dp, crtc_state->port_clock);
> -	if (new_link_rate < 0) {
> -		new_lane_count = reduce_lane_count(intel_dp, crtc_state-
> >lane_count);
> -		new_link_rate = intel_dp_max_common_rate(intel_dp);
> -	}
> -
> -	if (new_lane_count < 0)
> +	if (!reduce_link_params(intel_dp, crtc_state, &new_link_rate,
> +&new_lane_count))
>  		return -1;
> 
>  	if (intel_dp_is_edp(intel_dp) &&
> --
> 2.44.2