On Fri, Jul 28, 2023 at 09:41:41AM +0530, Ankit Nautiyal wrote:
> For DSC the min BPC is 8 for ICL+ and so the min pipe_bpp is 24.
> Check this condition for cases where bpc is forced by debugfs flag
> dsc_force_bpc. If the check fails, then WARN and ignore the debugfs
> flag.
>
> For MST case the pipe_bpp is already computed (hardcoded to be 24),
> and this check is not required.
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@xxxxxxxxx>
>
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_dp.c | 48 ++++++++++++++++---------
> 1 file changed, 31 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index f41de126a8d3..78ac8f4fd348 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -1697,6 +1697,12 @@ u8 intel_dp_dsc_min_src_input_bpc(struct drm_i915_private *i915)
> return 0;
> }
>
> +static
> +bool is_dsc_pipe_bpp_sufficient(struct drm_i915_private *i915, int pipe_bpp)
> +{
> + return pipe_bpp >= intel_dp_dsc_min_src_input_bpc(i915) * 3;
> +}
> +
> int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
> struct intel_crtc_state *pipe_config,
> struct drm_connector_state *conn_state,
> @@ -1708,7 +1714,6 @@ int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
> struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
> const struct drm_display_mode *adjusted_mode =
> &pipe_config->hw.adjusted_mode;
> - int pipe_bpp;
> int ret;
>
> pipe_config->fec_enable = !intel_dp_is_edp(intel_dp) &&
> @@ -1720,28 +1725,37 @@ int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
> if (!intel_dp_dsc_supports_format(intel_dp, pipe_config->output_format))
> return -EINVAL;
>
> - if (intel_dp->force_dsc_bpc && compute_pipe_bpp) {
> - pipe_bpp = intel_dp->force_dsc_bpc * 3;
> - drm_dbg_kms(&dev_priv->drm, "Input DSC BPC forced to %d\n",
> - intel_dp->force_dsc_bpc);
> - } else if (compute_pipe_bpp) {
> - pipe_bpp = intel_dp_dsc_compute_bpp(intel_dp, conn_state->max_requested_bpc);
> - } else {
> - pipe_bpp = pipe_config->pipe_bpp;
> - }
> + if (compute_pipe_bpp) {
> + int pipe_bpp;
> + int forced_bpp = intel_dp->force_dsc_bpc * 3;
>
> - if (pipe_bpp < intel_dp_dsc_min_src_input_bpc(dev_priv) * 3) {
> - drm_dbg_kms(&dev_priv->drm,
> - "Computed BPC less than min supported by source for DSC\n");
> - return -EINVAL;
> + if (forced_bpp && is_dsc_pipe_bpp_sufficient(dev_priv, forced_bpp)) {
> + pipe_bpp = forced_bpp;
> + drm_dbg_kms(&dev_priv->drm, "Input DSC BPC forced to %d\n",
> + intel_dp->force_dsc_bpc);
> + } else {
> + drm_WARN(&dev_priv->drm, forced_bpp,
> + "Cannot force DSC BPC:%d, due to DSC BPC limits\n",
> + intel_dp->force_dsc_bpc);
> +
> + pipe_bpp = intel_dp_dsc_compute_bpp(intel_dp,
> + conn_state->max_requested_bpc);
> +
> + if (!is_dsc_pipe_bpp_sufficient(dev_priv, pipe_bpp)) {
> + drm_dbg_kms(&dev_priv->drm,
> + "Computed BPC less than min supported by source for DSC\n");
> + return -EINVAL;
> + }
> + }
> +
> + pipe_config->pipe_bpp = pipe_bpp;
> }
>
> /*
> - * For now enable DSC for max bpp, max link rate, max lane count.
> + * For now enable DSC for max link rate, max lane count.
> * Optimize this later for the minimum possible link rate/lane count
> * with DSC enabled for the requested mode.
> */
> - pipe_config->pipe_bpp = pipe_bpp;
> pipe_config->port_clock = limits->max_rate;
> pipe_config->lane_count = limits->max_lane_count;
>
> @@ -1770,7 +1784,7 @@ int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
> adjusted_mode->crtc_hdisplay,
> pipe_config->bigjoiner_pipes,
> pipe_config->output_format,
> - pipe_bpp,
> + pipe_config->pipe_bpp,
> timeslots);
> if (!dsc_max_compressed_bpp) {
> drm_dbg_kms(&dev_priv->drm,
> --
> 2.40.1
>
