[PATCH 1/1] drm/i915: Allow bigjoiner for MST

[Manasi Navare]

Thanks Vidya for the v3,
this LGTM,

Reviewed-by: Manasi Navare <navaremanasi at chromium.org>

Manasi

On Wed, Mar 6, 2024 at 9:31 PM Vidya Srinivas <vidya.srinivas at intel.com> wrote:
>
> We need bigjoiner support with MST functionality
> for MST monitor resolutions > 5K to work.
> Adding support for the same.
>
> v2: Addressed review comments from Jani.
> Revert rejection of MST bigjoiner modes and add
> functionality
>
> v3: Fixed pipe_mismatch WARN for mst_master_transcoder
> Credits-to: Manasi Navare <navaremanasi at chromium.org>
>
> Signed-off-by: Vidya Srinivas <vidya.srinivas at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_ddi.c    |  6 ++++--
>  drivers/gpu/drm/i915/display/intel_dp_mst.c | 17 +++++++++--------
>  2 files changed, 13 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index c587a8efeafc..41998022ed07 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -3902,9 +3902,11 @@ static void intel_ddi_read_func_ctl(struct intel_encoder *encoder,
>                 pipe_config->lane_count =
>                         ((temp & DDI_PORT_WIDTH_MASK) >> DDI_PORT_WIDTH_SHIFT) + 1;
>
> -               if (DISPLAY_VER(dev_priv) >= 12)
> -                       pipe_config->mst_master_transcoder =
> +               if (DISPLAY_VER(dev_priv) >= 12) {
> +                       if (!intel_crtc_is_bigjoiner_slave(pipe_config))
> +                               pipe_config->mst_master_transcoder =
>                                         REG_FIELD_GET(TRANS_DDI_MST_TRANSPORT_SELECT_MASK, temp);
> +               }
>
>                 intel_cpu_transcoder_get_m1_n1(crtc, cpu_transcoder,
>                                                &pipe_config->dp_m_n);
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> index db1254b036f1..c5e7293c13eb 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -525,6 +525,7 @@ static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
>  {
>         struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
>         struct intel_atomic_state *state = to_intel_atomic_state(conn_state->state);
> +       struct intel_crtc *crtc = to_intel_crtc(pipe_config->uapi.crtc);
>         struct intel_dp_mst_encoder *intel_mst = enc_to_mst(encoder);
>         struct intel_dp *intel_dp = &intel_mst->primary->dp;
>         const struct intel_connector *connector =
> @@ -542,6 +543,10 @@ static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
>         if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)
>                 return -EINVAL;
>
> +       if (intel_dp_need_bigjoiner(intel_dp, adjusted_mode->crtc_hdisplay,
> +                                   adjusted_mode->crtc_clock))
> +               pipe_config->bigjoiner_pipes = GENMASK(crtc->pipe + 1, crtc->pipe);
> +
>         pipe_config->sink_format = INTEL_OUTPUT_FORMAT_RGB;
>         pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB;
>         pipe_config->has_pch_encoder = false;
> @@ -1330,12 +1335,6 @@ intel_dp_mst_mode_valid_ctx(struct drm_connector *connector,
>          *   corresponding link capabilities of the sink) in case the
>          *   stream is uncompressed for it by the last branch device.
>          */
> -       if (mode_rate > max_rate || mode->clock > max_dotclk ||
> -           drm_dp_calc_pbn_mode(mode->clock, min_bpp << 4) > port->full_pbn) {
> -               *status = MODE_CLOCK_HIGH;
> -               return 0;
> -       }
> -
>         if (mode->clock < 10000) {
>                 *status = MODE_CLOCK_LOW;
>                 return 0;
> @@ -1349,8 +1348,10 @@ intel_dp_mst_mode_valid_ctx(struct drm_connector *connector,
>         if (intel_dp_need_bigjoiner(intel_dp, mode->hdisplay, target_clock)) {
>                 bigjoiner = true;
>                 max_dotclk *= 2;
> +       }
>
> -               /* TODO: add support for bigjoiner */
> +       if (mode_rate > max_rate || mode->clock > max_dotclk ||
> +           drm_dp_calc_pbn_mode(mode->clock, min_bpp << 4) > port->full_pbn) {
>                 *status = MODE_CLOCK_HIGH;
>                 return 0;
>         }
> @@ -1397,7 +1398,7 @@ intel_dp_mst_mode_valid_ctx(struct drm_connector *connector,
>                 return 0;
>         }
>
> -       *status = intel_mode_valid_max_plane_size(dev_priv, mode, false);
> +       *status = intel_mode_valid_max_plane_size(dev_priv, mode, bigjoiner);
>         return 0;
>  }
>
> --
> 2.33.0
>