diff mbox series

[v4] drm/i915/dp: Add FEC Enable Retry mechanism

Message ID 20241024061002.4085137-1-chaitanya.kumar.borah@intel.com (mailing list archive)
State New, archived
Headers show
Series [v4] drm/i915/dp: Add FEC Enable Retry mechanism | expand

Commit Message

Chaitanya Kumar Borah Oct. 24, 2024, 6:10 a.m. UTC
Currently, even though there is a bit to control FEC enable/disable
individually, the FEC Decode Enable sequence is sent by the SOC only
once TRANS_CONF enable is set. This ties the FEC enabling too tightly
to modeset and therefore cannot be re-issued (in case of failure)
without a modeset.

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 a modeset. Hence allowing us to have a retry
mechanism in case the DPRX does not respond with an FEC_ENABLE
within certain amount of time.

While at it, replace struct drm_i915_private with struct intel_display

v4:
 - More code refactor [Jani]
 - use struct intel_display [Jani]
 - Optimize logging [Jani]

v3:
 - Make the commit message more legible [Jani]
 - Refactor code to re-use existing code [Jani]
 - Do away with platform dependent FEC enable checks [Jani]

v2:
 - Refactor code to avoid duplication and improve readability [Jani]
 - In case of PTL, wait for FEC status directly after FEC enable [Srikanth]
 - Wait for FEC_ENABLE_LIVE_STATUS to be cleared before
   re-enabling FEC [Srikanth]

Signed-off-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
---
 drivers/gpu/drm/i915/display/intel_ddi.c | 81 +++++++++++++++++-------
 drivers/gpu/drm/i915/display/intel_ddi.h |  6 +-
 2 files changed, 61 insertions(+), 26 deletions(-)

Comments

Jani Nikula Oct. 24, 2024, 9:30 a.m. UTC | #1
On Thu, 24 Oct 2024, Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com> wrote:
> Currently, even though there is a bit to control FEC enable/disable
> individually, the FEC Decode Enable sequence is sent by the SOC only
> once TRANS_CONF enable is set. This ties the FEC enabling too tightly
> to modeset and therefore cannot be re-issued (in case of failure)
> without a modeset.
>
> 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 a modeset. Hence allowing us to have a retry
> mechanism in case the DPRX does not respond with an FEC_ENABLE
> within certain amount of time.
>
> While at it, replace struct drm_i915_private with struct intel_display
>
> v4:
>  - More code refactor [Jani]
>  - use struct intel_display [Jani]
>  - Optimize logging [Jani]
>
> v3:
>  - Make the commit message more legible [Jani]
>  - Refactor code to re-use existing code [Jani]
>  - Do away with platform dependent FEC enable checks [Jani]
>
> v2:
>  - Refactor code to avoid duplication and improve readability [Jani]
>  - In case of PTL, wait for FEC status directly after FEC enable [Srikanth]
>  - Wait for FEC_ENABLE_LIVE_STATUS to be cleared before
>    re-enabling FEC [Srikanth]
>
> Signed-off-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_ddi.c | 81 +++++++++++++++++-------
>  drivers/gpu/drm/i915/display/intel_ddi.h |  6 +-
>  2 files changed, 61 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index fe1ded6707f9..ce95263d74ea 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -2256,9 +2256,9 @@ 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 int wait_for_fec_detected(struct drm_dp_aux *aux, bool enabled)
>  {
> -	struct drm_i915_private *i915 = to_i915(aux->drm_dev);
> +	struct intel_display *display = to_intel_display(aux->drm_dev);
>  	int mask = enabled ? DP_FEC_DECODE_EN_DETECTED : DP_FEC_DECODE_DIS_DETECTED;
>  	int status;
>  	int err;
> @@ -2267,57 +2267,92 @@ static void wait_for_fec_detected(struct drm_dp_aux *aux, bool enabled)
>  				 status & mask || status < 0,
>  				 10000, 200000);
>  
> -	if (!err && status >= 0)
> -		return;
> +	if (err || status < 0) {
> +		drm_dbg_kms(display->drm,
> +			    "Failed waiting for FEC %s to get detected: %d (status %d)\n",
> +			    str_enabled_disabled(enabled), err, status);
> +		return err ? err : status;
> +	}
>  
> -	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);
> +	return 0;
>  }
>  
> -void intel_ddi_wait_for_fec_status(struct intel_encoder *encoder,
> -				   const struct intel_crtc_state *crtc_state,
> -				   bool enabled)
> +int 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_display *display = to_intel_display(encoder);
>  	struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
>  	int ret;
>  
>  	if (!crtc_state->fec_enable)
> -		return;
> +		return 0;
>  
>  	if (enabled)
> -		ret = intel_de_wait_for_set(i915, dp_tp_status_reg(encoder, crtc_state),
> +		ret = intel_de_wait_for_set(display, 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),
> +		ret = intel_de_wait_for_clear(display, dp_tp_status_reg(encoder, crtc_state),
>  					      DP_TP_STATUS_FEC_ENABLE_LIVE, 1);
>  
> -	if (ret)
> -		drm_err(&i915->drm,
> +	if (ret) {
> +		drm_err(display->drm,
>  			"Timeout waiting for FEC live state to get %s\n",
>  			str_enabled_disabled(enabled));
> -
> +		return ret;
> +	}

So the functional change here is that we skip the below wait if we timed
out above. I think it's probably fine.

I also think the patch evolved to be considerably neater than the
original. What do you think?

Reviewed-by: Jani Nikula <jani.nikula@intel.com>


>  	/*
>  	 * 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);
> +	if (enabled) {
> +		ret = wait_for_fec_detected(&intel_dp->aux, enabled);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
>  }
>  
>  static void intel_ddi_enable_fec(struct intel_encoder *encoder,
>  				 const struct intel_crtc_state *crtc_state)
>  {
> -	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> +	struct intel_display *display = to_intel_display(encoder);
> +	int i;
> +	int ret;
>  
>  	if (!crtc_state->fec_enable)
>  		return;
>  
> -	intel_de_rmw(dev_priv, dp_tp_ctl_reg(encoder, crtc_state),
> +	intel_de_rmw(display, dp_tp_ctl_reg(encoder, crtc_state),
>  		     0, DP_TP_CTL_FEC_ENABLE);
> +
> +	if (DISPLAY_VER(display) < 30)
> +		return;
> +
> +	ret = intel_ddi_wait_for_fec_status(encoder, crtc_state, true);
> +	if (!ret)
> +		return;
> +
> +	for (i = 0; i < 3; i++) {
> +		drm_dbg_kms(display->drm, "Retry FEC enabling\n");
> +
> +		intel_de_rmw(display, dp_tp_ctl_reg(encoder, crtc_state),
> +			     DP_TP_CTL_FEC_ENABLE, 0);
> +
> +		ret = intel_ddi_wait_for_fec_status(encoder, crtc_state, false);
> +		if (ret)
> +			continue;
> +
> +		intel_de_rmw(display, dp_tp_ctl_reg(encoder, crtc_state),
> +			     0, DP_TP_CTL_FEC_ENABLE);
> +
> +		ret = intel_ddi_wait_for_fec_status(encoder, crtc_state, true);
> +		if (!ret)
> +			return;
> +	}
> +
> +	drm_err(display->drm, "Failed to enable FEC after retries\n");
>  }
>  
>  static void intel_ddi_disable_fec(struct intel_encoder *encoder,
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.h b/drivers/gpu/drm/i915/display/intel_ddi.h
> index 6d85422bdefe..640851d46b1b 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.h
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.h
> @@ -63,9 +63,9 @@ 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);
> +int 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);
Chaitanya Kumar Borah Oct. 24, 2024, 9:42 a.m. UTC | #2
Hello Jani,

> -----Original Message-----
> From: Jani Nikula <jani.nikula@linux.intel.com>
> Sent: Thursday, October 24, 2024 3:00 PM
> To: Borah, Chaitanya Kumar <chaitanya.kumar.borah@intel.com>; intel-
> gfx@lists.freedesktop.org; intel-xe@lists.freedesktop.org
> Cc: Srikanth V, NagaVenkata <nagavenkata.srikanth.v@intel.com>; Deak, Imre
> <imre.deak@intel.com>
> Subject: Re: [v4] drm/i915/dp: Add FEC Enable Retry mechanism
> 
> On Thu, 24 Oct 2024, Chaitanya Kumar Borah
> <chaitanya.kumar.borah@intel.com> wrote:
> > Currently, even though there is a bit to control FEC enable/disable
> > individually, the FEC Decode Enable sequence is sent by the SOC only
> > once TRANS_CONF enable is set. This ties the FEC enabling too tightly
> > to modeset and therefore cannot be re-issued (in case of failure)
> > without a modeset.
> >
> > 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 a modeset. Hence allowing us to have a retry
> > mechanism in case the DPRX does not respond with an FEC_ENABLE within
> > certain amount of time.
> >
> > While at it, replace struct drm_i915_private with struct intel_display
> >
> > v4:
> >  - More code refactor [Jani]
> >  - use struct intel_display [Jani]
> >  - Optimize logging [Jani]
> >
> > v3:
> >  - Make the commit message more legible [Jani]
> >  - Refactor code to re-use existing code [Jani]
> >  - Do away with platform dependent FEC enable checks [Jani]
> >
> > v2:
> >  - Refactor code to avoid duplication and improve readability [Jani]
> >  - In case of PTL, wait for FEC status directly after FEC enable
> > [Srikanth]
> >  - Wait for FEC_ENABLE_LIVE_STATUS to be cleared before
> >    re-enabling FEC [Srikanth]
> >
> > Signed-off-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_ddi.c | 81
> > +++++++++++++++++-------  drivers/gpu/drm/i915/display/intel_ddi.h |
> > 6 +-
> >  2 files changed, 61 insertions(+), 26 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c
> > b/drivers/gpu/drm/i915/display/intel_ddi.c
> > index fe1ded6707f9..ce95263d74ea 100644
> > --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> > @@ -2256,9 +2256,9 @@ 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 int wait_for_fec_detected(struct drm_dp_aux *aux, bool
> > +enabled)
> >  {
> > -	struct drm_i915_private *i915 = to_i915(aux->drm_dev);
> > +	struct intel_display *display = to_intel_display(aux->drm_dev);
> >  	int mask = enabled ? DP_FEC_DECODE_EN_DETECTED :
> DP_FEC_DECODE_DIS_DETECTED;
> >  	int status;
> >  	int err;
> > @@ -2267,57 +2267,92 @@ static void wait_for_fec_detected(struct
> drm_dp_aux *aux, bool enabled)
> >  				 status & mask || status < 0,
> >  				 10000, 200000);
> >
> > -	if (!err && status >= 0)
> > -		return;
> > +	if (err || status < 0) {
> > +		drm_dbg_kms(display->drm,
> > +			    "Failed waiting for FEC %s to get detected: %d
> (status %d)\n",
> > +			    str_enabled_disabled(enabled), err, status);
> > +		return err ? err : status;
> > +	}
> >
> > -	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);
> > +	return 0;
> >  }
> >
> > -void intel_ddi_wait_for_fec_status(struct intel_encoder *encoder,
> > -				   const struct intel_crtc_state *crtc_state,
> > -				   bool enabled)
> > +int 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_display *display = to_intel_display(encoder);
> >  	struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
> >  	int ret;
> >
> >  	if (!crtc_state->fec_enable)
> > -		return;
> > +		return 0;
> >
> >  	if (enabled)
> > -		ret = intel_de_wait_for_set(i915, dp_tp_status_reg(encoder,
> crtc_state),
> > +		ret = intel_de_wait_for_set(display,
> 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),
> > +		ret = intel_de_wait_for_clear(display,
> dp_tp_status_reg(encoder,
> > +crtc_state),
> >  					      DP_TP_STATUS_FEC_ENABLE_LIVE,
> 1);
> >
> > -	if (ret)
> > -		drm_err(&i915->drm,
> > +	if (ret) {
> > +		drm_err(display->drm,
> >  			"Timeout waiting for FEC live state to get %s\n",
> >  			str_enabled_disabled(enabled));
> > -
> > +		return ret;
> > +	}
> 
> So the functional change here is that we skip the below wait if we timed out
> above. I think it's probably fine.
> 

Since we're no longer using the crash-and-burn approach and making the functions return values now, I thought it would be good to do the same here.

> I also think the patch evolved to be considerably neater than the original.
> What do you think?
> 

Agreed. It gives me framework for the future too. Thanks a lot for the review.

> Reviewed-by: Jani Nikula <jani.nikula@intel.com>
> 
> 
> >  	/*
> >  	 * 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);
> > +	if (enabled) {
> > +		ret = wait_for_fec_detected(&intel_dp->aux, enabled);
> > +		if (ret)
> > +			return ret;
> > +	}
> > +
> > +	return 0;
> >  }
> >
> >  static void intel_ddi_enable_fec(struct intel_encoder *encoder,
> >  				 const struct intel_crtc_state *crtc_state)  {
> > -	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> > +	struct intel_display *display = to_intel_display(encoder);
> > +	int i;
> > +	int ret;
> >
> >  	if (!crtc_state->fec_enable)
> >  		return;
> >
> > -	intel_de_rmw(dev_priv, dp_tp_ctl_reg(encoder, crtc_state),
> > +	intel_de_rmw(display, dp_tp_ctl_reg(encoder, crtc_state),
> >  		     0, DP_TP_CTL_FEC_ENABLE);
> > +
> > +	if (DISPLAY_VER(display) < 30)
> > +		return;
> > +
> > +	ret = intel_ddi_wait_for_fec_status(encoder, crtc_state, true);
> > +	if (!ret)
> > +		return;
> > +
> > +	for (i = 0; i < 3; i++) {
> > +		drm_dbg_kms(display->drm, "Retry FEC enabling\n");
> > +
> > +		intel_de_rmw(display, dp_tp_ctl_reg(encoder, crtc_state),
> > +			     DP_TP_CTL_FEC_ENABLE, 0);
> > +
> > +		ret = intel_ddi_wait_for_fec_status(encoder, crtc_state, false);
> > +		if (ret)
> > +			continue;
> > +
> > +		intel_de_rmw(display, dp_tp_ctl_reg(encoder, crtc_state),
> > +			     0, DP_TP_CTL_FEC_ENABLE);
> > +
> > +		ret = intel_ddi_wait_for_fec_status(encoder, crtc_state, true);
> > +		if (!ret)
> > +			return;
> > +	}
> > +
> > +	drm_err(display->drm, "Failed to enable FEC after retries\n");
> >  }
> >
> >  static void intel_ddi_disable_fec(struct intel_encoder *encoder, diff
> > --git a/drivers/gpu/drm/i915/display/intel_ddi.h
> > b/drivers/gpu/drm/i915/display/intel_ddi.h
> > index 6d85422bdefe..640851d46b1b 100644
> > --- a/drivers/gpu/drm/i915/display/intel_ddi.h
> > +++ b/drivers/gpu/drm/i915/display/intel_ddi.h
> > @@ -63,9 +63,9 @@ 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);
> > +int 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);
> 
> --
> Jani Nikula, Intel
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index fe1ded6707f9..ce95263d74ea 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -2256,9 +2256,9 @@  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 int wait_for_fec_detected(struct drm_dp_aux *aux, bool enabled)
 {
-	struct drm_i915_private *i915 = to_i915(aux->drm_dev);
+	struct intel_display *display = to_intel_display(aux->drm_dev);
 	int mask = enabled ? DP_FEC_DECODE_EN_DETECTED : DP_FEC_DECODE_DIS_DETECTED;
 	int status;
 	int err;
@@ -2267,57 +2267,92 @@  static void wait_for_fec_detected(struct drm_dp_aux *aux, bool enabled)
 				 status & mask || status < 0,
 				 10000, 200000);
 
-	if (!err && status >= 0)
-		return;
+	if (err || status < 0) {
+		drm_dbg_kms(display->drm,
+			    "Failed waiting for FEC %s to get detected: %d (status %d)\n",
+			    str_enabled_disabled(enabled), err, status);
+		return err ? err : status;
+	}
 
-	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);
+	return 0;
 }
 
-void intel_ddi_wait_for_fec_status(struct intel_encoder *encoder,
-				   const struct intel_crtc_state *crtc_state,
-				   bool enabled)
+int 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_display *display = to_intel_display(encoder);
 	struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
 	int ret;
 
 	if (!crtc_state->fec_enable)
-		return;
+		return 0;
 
 	if (enabled)
-		ret = intel_de_wait_for_set(i915, dp_tp_status_reg(encoder, crtc_state),
+		ret = intel_de_wait_for_set(display, 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),
+		ret = intel_de_wait_for_clear(display, dp_tp_status_reg(encoder, crtc_state),
 					      DP_TP_STATUS_FEC_ENABLE_LIVE, 1);
 
-	if (ret)
-		drm_err(&i915->drm,
+	if (ret) {
+		drm_err(display->drm,
 			"Timeout waiting for FEC live state to get %s\n",
 			str_enabled_disabled(enabled));
-
+		return ret;
+	}
 	/*
 	 * 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);
+	if (enabled) {
+		ret = wait_for_fec_detected(&intel_dp->aux, enabled);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
 }
 
 static void intel_ddi_enable_fec(struct intel_encoder *encoder,
 				 const struct intel_crtc_state *crtc_state)
 {
-	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
+	struct intel_display *display = to_intel_display(encoder);
+	int i;
+	int ret;
 
 	if (!crtc_state->fec_enable)
 		return;
 
-	intel_de_rmw(dev_priv, dp_tp_ctl_reg(encoder, crtc_state),
+	intel_de_rmw(display, dp_tp_ctl_reg(encoder, crtc_state),
 		     0, DP_TP_CTL_FEC_ENABLE);
+
+	if (DISPLAY_VER(display) < 30)
+		return;
+
+	ret = intel_ddi_wait_for_fec_status(encoder, crtc_state, true);
+	if (!ret)
+		return;
+
+	for (i = 0; i < 3; i++) {
+		drm_dbg_kms(display->drm, "Retry FEC enabling\n");
+
+		intel_de_rmw(display, dp_tp_ctl_reg(encoder, crtc_state),
+			     DP_TP_CTL_FEC_ENABLE, 0);
+
+		ret = intel_ddi_wait_for_fec_status(encoder, crtc_state, false);
+		if (ret)
+			continue;
+
+		intel_de_rmw(display, dp_tp_ctl_reg(encoder, crtc_state),
+			     0, DP_TP_CTL_FEC_ENABLE);
+
+		ret = intel_ddi_wait_for_fec_status(encoder, crtc_state, true);
+		if (!ret)
+			return;
+	}
+
+	drm_err(display->drm, "Failed to enable FEC after retries\n");
 }
 
 static void intel_ddi_disable_fec(struct intel_encoder *encoder,
diff --git a/drivers/gpu/drm/i915/display/intel_ddi.h b/drivers/gpu/drm/i915/display/intel_ddi.h
index 6d85422bdefe..640851d46b1b 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.h
+++ b/drivers/gpu/drm/i915/display/intel_ddi.h
@@ -63,9 +63,9 @@  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);
+int 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);