[PATCH] drm/i915/dp: Add FEC Enable Retry mechanism
Srikanth V, NagaVenkata
nagavenkata.srikanth.v at intel.com
Wed Oct 30 04:38:32 UTC 2024
Looks good to me.
Reviewed-by: Naga Venkata Srikanth V <nagavenkata.srikanth.v at intel.com>
> -----Original Message-----
> From: Intel-gfx-trybot <intel-gfx-trybot-bounces at lists.freedesktop.org> On
> Behalf Of Chaitanya Kumar Borah
> Sent: Wednesday, October 2, 2024 4:48 PM
> To: intel-gfx-trybot at lists.freedesktop.org
> Subject: [PATCH] drm/i915/dp: Add FEC Enable Retry mechanism
>
> From PTL, FEC_DECODE_EN sequence can be sent to a DPRX independent of
> TRANS_CONF enable. This allows us to re-issue an FEC_DECODE_EN
> sequence without re-doing the whole mode set sequence. This separate
> control over FEC_ECODE_EN/DIS sequence enables us to have a retry
> mechanism in case the DPRX does not respond with an FEC_ENABLE within
> the stipulated 5ms.
>
> Signed-off-by: Chaitanya Kumar Borah <chaitanya.kumar.borah at intel.com>
> ---
> drivers/gpu/drm/i915/display/intel_ddi.c | 81 +++++++++++++++++----
> drivers/gpu/drm/i915/display/intel_ddi.h | 2 +-
> drivers/gpu/drm/i915/display/intel_dp_mst.c | 4 +-
> 3 files changed, 69 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c
> b/drivers/gpu/drm/i915/display/intel_ddi.c
> index fe1ded6707f9..dee60d8c773a 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -2256,30 +2256,76 @@ static int read_fec_detected_status(struct
> drm_dp_aux *aux)
> return status;
> }
>
> -static void wait_for_fec_detected(struct drm_dp_aux *aux, bool enabled)
> +static void retry_fec_enable(struct intel_encoder *encoder,
> + const struct intel_crtc_state *crtc_state,
> + struct drm_dp_aux *aux)
> +{
> + struct drm_i915_private *i915 = to_i915(aux->drm_dev);
> + int ret = 0;
> +
> + 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 disabled
> during
> +retry\n");
> +
> + /* Clear FEC enable */
> + intel_de_rmw(i915, dp_tp_ctl_reg(encoder, crtc_state),
> + DP_TP_CTL_FEC_ENABLE, 0);
> +
> + /* Set FEC enable */
> + intel_de_rmw(i915, dp_tp_ctl_reg(encoder, crtc_state),
> + 0, DP_TP_CTL_FEC_ENABLE);
> +
> + ret = intel_de_wait_for_set(i915, dp_tp_status_reg(encoder,
> crtc_state),
> + DP_TP_STATUS_FEC_ENABLE_LIVE, 1);
> + if (!ret)
> + drm_dbg_kms(&i915->drm,
> + "Timeout waiting for FEC live state to get
> enabled"); }
> +
> +static void wait_for_fec_detected(struct intel_encoder *encoder,
> + const struct intel_crtc_state *crtc_state,
> + struct drm_dp_aux *aux, bool enabled, bool retry)
> {
> 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;
> + int max_retries = retry ? 3 : 1;
>
> - err = readx_poll_timeout(read_fec_detected_status, aux, status,
> - status & mask || status < 0,
> - 10000, 200000);
> + for (int retrycount = 0; retrycount < max_retries; retrycount++) {
> + err = readx_poll_timeout(read_fec_detected_status, aux,
> status,
> + status & mask || status < 0,
> + retry ? 500 : 10000,
> + retry ? 5000 : 20000);
>
> - if (!err && status >= 0)
> - return;
> + if (!err && status >= 0)
> + return;
>
> - if (err == -ETIMEDOUT)
> - drm_dbg_kms(&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);
> + if (err == -ETIMEDOUT) {
> + drm_dbg_kms(&i915->drm,
> + "Timeout waiting for FEC %s to get
> detected, retrying (%d/%d)\n",
> + str_enabled_disabled(enabled), retrycount
> + 1, max_retries);
> +
> + /* If retry is requested and FEC is being enabled, try
> re-enabling */
> + if (retry && enabled)
> + retry_fec_enable(encoder, crtc_state, aux);
> + } else {
> + drm_dbg_kms(&i915->drm, "FEC detected status
> read error: %d\n", status);
> + return;
> + }
> + }
> +
> + /* If retries are exhausted or not enabled, print final failure message
> */
> + drm_err(&i915->drm, "FEC %s Failed after %d attempts\n",
> + str_enabled_disabled(enabled), max_retries);
> }
>
> void intel_ddi_wait_for_fec_status(struct intel_encoder *encoder,
> const struct intel_crtc_state *crtc_state,
> - bool enabled)
> + bool enabled, bool retry)
> {
> struct drm_i915_private *i915 = to_i915(crtc_state->uapi.crtc->dev);
> struct intel_dp *intel_dp = enc_to_intel_dp(encoder); @@ -2305,7
> +2351,7 @@ void intel_ddi_wait_for_fec_status(struct intel_encoder
> *encoder,
> * FEC decoding disabling so skip waiting for that.
> */
> if (enabled)
> - wait_for_fec_detected(&intel_dp->aux, enabled);
> + wait_for_fec_detected(encoder, crtc_state, &intel_dp->aux,
> true,
> +retry);
> }
>
> static void intel_ddi_enable_fec(struct intel_encoder *encoder, @@ -2318,6
> +2364,9 @@ static void intel_ddi_enable_fec(struct intel_encoder *encoder,
>
> intel_de_rmw(dev_priv, dp_tp_ctl_reg(encoder, crtc_state),
> 0, DP_TP_CTL_FEC_ENABLE);
> +
> + if (DISPLAY_VER(dev_priv) >= 30)
> + intel_ddi_wait_for_fec_status(encoder, crtc_state, true,
> true);
> }
>
> static void intel_ddi_disable_fec(struct intel_encoder *encoder, @@ -3010,7
> +3059,7 @@ static void intel_disable_ddi_buf(struct intel_encoder *encoder,
> disable_ddi_buf(encoder, crtc_state);
> }
>
> - intel_ddi_wait_for_fec_status(encoder, crtc_state, false);
> + intel_ddi_wait_for_fec_status(encoder, crtc_state, false, false);
> }
>
> static void intel_ddi_post_disable_dp(struct intel_atomic_state *state, @@ -
> 3383,6 +3432,7 @@ static void intel_enable_ddi(struct intel_atomic_state
> *state,
> const struct intel_crtc_state *crtc_state,
> const struct drm_connector_state *conn_state) {
> + struct drm_i915_private *i915 = to_i915(crtc_state->uapi.crtc->dev);
> struct intel_display *display = to_intel_display(encoder);
> struct intel_crtc *pipe_crtc;
> int i;
> @@ -3394,7 +3444,8 @@ static void intel_enable_ddi(struct
> intel_atomic_state *state,
>
> intel_enable_transcoder(crtc_state);
>
> - intel_ddi_wait_for_fec_status(encoder, crtc_state, true);
> + if (DISPLAY_VER(i915) < 30)
> + intel_ddi_wait_for_fec_status(encoder, crtc_state, true,
> false);
>
> for_each_pipe_crtc_modeset_enable(display, pipe_crtc, crtc_state, i)
> {
> const struct intel_crtc_state *pipe_crtc_state = diff --git
> a/drivers/gpu/drm/i915/display/intel_ddi.h
> b/drivers/gpu/drm/i915/display/intel_ddi.h
> index 6d85422bdefe..981e7702e11e 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.h
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.h
> @@ -65,7 +65,7 @@ void intel_ddi_enable_transcoder_clock(struct
> intel_encoder *encoder, 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);
> + bool enabled, bool retry);
> 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 732d7543ad06..226ac9a73a55 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -1289,8 +1289,8 @@ 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);
> + if (first_mst_stream && DISPLAY_VER(dev_priv) < 30)
> + intel_ddi_wait_for_fec_status(encoder, pipe_config, true,
> false);
>
> ret = drm_dp_add_payload_part2(&intel_dp->mst_mgr,
>
> drm_atomic_get_mst_payload_state(mst_state,
> --
> 2.25.1
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