On Tue, Oct 24, 2023 at 04:09:14AM +0300, Imre Deak wrote:
> As required by the DP standard wait for the sink to detect the FEC
> decode enabling symbol sent by the source.
>
> Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_ddi.c | 73 +++++++++++++++++++++
> drivers/gpu/drm/i915/display/intel_ddi.h | 3 +
> drivers/gpu/drm/i915/display/intel_dp_mst.c | 4 ++
> 3 files changed, 80 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index dac3b59758af7..6f9d0f2ff3d9a 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -25,6 +25,7 @@
> *
> */
>
> +#include <linux/iopoll.h>
> #include <linux/string_helpers.h>
>
> #include <drm/display/drm_scdc_helper.h>
> @@ -2220,6 +2221,74 @@ static void intel_dp_sink_set_fec_ready(struct intel_dp *intel_dp,
> if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_FEC_CONFIGURATION, DP_FEC_READY) <= 0)
> drm_dbg_kms(&i915->drm,
> "Failed to set FEC_READY in the sink\n");
> +
> + if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_FEC_STATUS,
> + DP_FEC_DECODE_EN_DETECTED | DP_FEC_DECODE_DIS_DETECTED) <= 0)
> + drm_dbg_kms(&i915->drm, "Failed to clear FEC detected flags\n");
> +}
> +
> +static int read_fec_detected_status(struct drm_dp_aux *aux)
> +{
> + int ret;
> + u8 status;
> +
> + ret = drm_dp_dpcd_readb(aux, DP_FEC_STATUS, &status);
> + if (ret < 0)
> + return ret;
> +
> + return status;
> +}
> +
> +static void wait_for_fec_detected(struct drm_dp_aux *aux, bool enabled)
> +{
> + struct drm_i915_private *i915 = to_i915(aux->drm_dev);
> + int mask = enabled ? DP_FEC_DECODE_EN_DETECTED : DP_FEC_DECODE_DIS_DETECTED;
> + int status;
> + int err;
> +
> + err = readx_poll_timeout(read_fec_detected_status, aux, status,
> + status & mask || status < 0,
> + 10000, 200000);
> +
> + if (!err && status >= 0)
> + return;
> +
> + if (err == -ETIMEDOUT)
> + drm_err(&i915->drm, "Timeout waiting for FEC %s to get detected\n",
> + str_enabled_disabled(enabled));
> + else
> + drm_dbg_kms(&i915->drm, "FEC detected status read error: %d\n", status);
> +}
> +
> +void intel_ddi_wait_for_fec_status(struct intel_encoder *encoder,
> + const struct intel_crtc_state *crtc_state,
> + bool enabled)
> +{
> + struct drm_i915_private *i915 = to_i915(crtc_state->uapi.crtc->dev);
> + struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
> + int ret;
> +
> + if (!crtc_state->fec_enable)
> + return;
> +
> + if (enabled)
> + ret = intel_de_wait_for_set(i915, dp_tp_status_reg(encoder, crtc_state),
> + DP_TP_STATUS_FEC_ENABLE_LIVE, 1);
> + else
> + ret = intel_de_wait_for_clear(i915, dp_tp_status_reg(encoder, crtc_state),
> + DP_TP_STATUS_FEC_ENABLE_LIVE, 1);
> +
> + if (ret)
> + drm_err(&i915->drm,
> + "Timeout waiting for FEC live state to get %s\n",
> + str_enabled_disabled(enabled));
> +
> + /*
> + * At least the Synoptics MST hub doesn't set the detected flag for
> + * FEC decoding disabling so skip waiting for that.
> + */
> + if (enabled)
> + wait_for_fec_detected(&intel_dp->aux, enabled);
> }
>
> static void intel_ddi_enable_fec(struct intel_encoder *encoder,
> @@ -2887,6 +2956,8 @@ static void intel_disable_ddi_buf(struct intel_encoder *encoder,
> } else {
> disable_ddi_buf(encoder, crtc_state);
> }
> +
> + intel_ddi_wait_for_fec_status(encoder, crtc_state, false);
> }
>
> static void intel_ddi_post_disable_dp(struct intel_atomic_state *state,
> @@ -3248,6 +3319,8 @@ static void intel_enable_ddi(struct intel_atomic_state *state,
> if (!intel_crtc_is_bigjoiner_slave(crtc_state))
> intel_ddi_enable_transcoder_func(encoder, crtc_state);
>
> + intel_ddi_wait_for_fec_status(encoder, crtc_state, true);
> +
> /* Enable/Disable DP2.0 SDP split config before transcoder */
> intel_audio_sdp_split_update(crtc_state);
>
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.h b/drivers/gpu/drm/i915/display/intel_ddi.h
> index 4999c0ee229bd..e939b93fc81c2 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.h
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.h
> @@ -60,6 +60,9 @@ void intel_ddi_disable_transcoder_func(const struct intel_crtc_state *crtc_state
> void intel_ddi_enable_transcoder_clock(struct intel_encoder *encoder,
> const struct intel_crtc_state *crtc_state);
> void intel_ddi_disable_transcoder_clock(const struct intel_crtc_state *crtc_state);
> +void intel_ddi_wait_for_fec_status(struct intel_encoder *encoder,
> + const struct intel_crtc_state *crtc_state,
> + bool enabled);
> void intel_ddi_set_dp_msa(const struct intel_crtc_state *crtc_state,
> const struct drm_connector_state *conn_state);
> bool intel_ddi_connector_get_hw_state(struct intel_connector *intel_connector);
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> index b7a9ce40cf59a..a1ea75cd5ea84 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -853,6 +853,7 @@ static void intel_mst_enable_dp(struct intel_atomic_state *state,
> struct drm_dp_mst_topology_state *mst_state =
> drm_atomic_get_new_mst_topology_state(&state->base, &intel_dp->mst_mgr);
> enum transcoder trans = pipe_config->cpu_transcoder;
> + bool first_mst_stream = intel_dp->active_mst_links == 1;
>
> drm_WARN_ON(&dev_priv->drm, pipe_config->has_pch_encoder);
>
> @@ -879,6 +880,9 @@ static void intel_mst_enable_dp(struct intel_atomic_state *state,
>
> wait_for_act_sent(encoder, pipe_config);
>
> + if (first_mst_stream)
> + intel_ddi_wait_for_fec_status(encoder, pipe_config, true);
> +
> drm_dp_add_payload_part2(&intel_dp->mst_mgr, &state->base,
> drm_atomic_get_mst_payload_state(mst_state, connector->port));
>
> --
> 2.39.2
>
