[Intel-gfx] [PATCH 4/4] drm/i915/dp: Ignore max_requested_bpc if its too low for DSC

[Kandpal, Suraj]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Ankit
> Nautiyal
> Sent: Tuesday, November 7, 2023 9:48 AM
> To: intel-gfx at lists.freedesktop.org
> Cc: Nikula, Jani <jani.nikula at intel.com>
> Subject: [Intel-gfx] [PATCH 4/4] drm/i915/dp: Ignore max_requested_bpc if its
> too low for DSC
> 
> At the moment, while choosing the input bpc for DSC, we take into account the
> max_requested_bpc property. This creates a problem, if the
> max_requested_bpc is lower than the minimum bpc required by source with
> DSC.
> 
> So consider max_requested_bpc if its within the limits that we can support with
> DSC.
> 
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp.c | 22 ++++++++++++++++++----
>  1 file changed, 18 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index abc718f1a878..ea4c42a5705e 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -1578,6 +1578,16 @@ u8 intel_dp_dsc_max_src_input_bpc(struct
> drm_i915_private *i915)
>  	return 12;
>  }
> 
> +static int
> +intel_dp_dsc_limit_max_bpc(int max_requested_bpc, int src_dsc_max_bpc,
> +int src_dsc_min_bpc) {
> +	/* Consider max_requested_bpc only if src can support it with DSC */
> +	if (max_requested_bpc >= src_dsc_min_bpc)
> +		return min(src_dsc_max_bpc, max_requested_bpc);
> +
> +	return src_dsc_max_bpc;
> +}
> +
>  int intel_dp_dsc_compute_max_bpp(const struct intel_connector *connector,
>  				 u8 max_req_bpc)
>  {
> @@ -1591,7 +1601,8 @@ int intel_dp_dsc_compute_max_bpp(const struct
> intel_connector *connector,
>  	if (!dsc_max_bpc)
>  		return dsc_max_bpc;
> 
> -	dsc_max_bpc = min_t(u8, dsc_max_bpc, max_req_bpc);
> +	dsc_max_bpc = intel_dp_dsc_limit_max_bpc(max_req_bpc,
> dsc_max_bpc,
> +
> intel_dp_dsc_min_src_input_bpc(i915));
> 
>  	num_bpc = drm_dp_dsc_sink_supported_input_bpcs(connector-
> >dp.dsc_dpcd,
>  						       dsc_bpc);
> @@ -1959,8 +1970,11 @@ bool is_dsc_pipe_bpp_sufficient(struct
> drm_i915_private *i915,  {
>  	u8 dsc_max_bpc, dsc_min_bpc, dsc_max_pipe_bpp,
> dsc_min_pipe_bpp;
> 
> -	dsc_max_bpc = min(intel_dp_dsc_max_src_input_bpc(i915),
> conn_state->max_requested_bpc);
>  	dsc_min_bpc = intel_dp_dsc_min_src_input_bpc(i915);
> +	dsc_max_bpc = intel_dp_dsc_max_src_input_bpc(i915);

Seems like this change could have been a part of the previous patch.

Regards,
Suraj Kandpal
> +
> +	dsc_max_bpc = intel_dp_dsc_limit_max_bpc(conn_state-
> >max_requested_bpc,
> +						 dsc_max_bpc, dsc_min_bpc);
> 
>  	dsc_max_pipe_bpp = min(dsc_max_bpc * 3, limits->pipe.max_bpp);
>  	dsc_min_pipe_bpp = max(dsc_min_bpc * 3, limits->pipe.min_bpp);
> @@ -2020,14 +2034,14 @@ static int intel_dp_dsc_compute_pipe_bpp(struct
> intel_dp *intel_dp,
>  		}
>  	}
> 
> +	dsc_min_bpc = intel_dp_dsc_min_src_input_bpc(i915);
>  	dsc_max_bpc = intel_dp_dsc_max_src_input_bpc(i915);
>  	if (!dsc_max_bpc)
>  		return -EINVAL;
> 
> -	dsc_max_bpc = min_t(u8, dsc_max_bpc, max_req_bpc);
> +	dsc_max_bpc = intel_dp_dsc_limit_max_bpc(max_req_bpc,
> dsc_max_bpc,
> +dsc_min_bpc);
>  	dsc_max_bpp = min(dsc_max_bpc * 3, limits->pipe.max_bpp);
> 
> -	dsc_min_bpc = intel_dp_dsc_min_src_input_bpc(i915);
>  	dsc_min_bpp = max(dsc_min_bpc * 3, limits->pipe.min_bpp);
> 
>  	/*
> --
> 2.40.1