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  3. [PATCH v3 0/4] drm/dp: Rework LTTPR transparent mode handling and add support to msm driver
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[PATCH v3 3/4] drm/i915/dp: Use the generic helper to control LTTPR transparent mode

Abel Vesa posted 4 patches 1 year, 1 month ago
There is a newer version of this series
[PATCH v3 3/4] drm/i915/dp: Use the generic helper to control LTTPR transparent mode
Posted by Abel Vesa 1 year, 1 month ago 
LTTPRs operating modes are defined by the DisplayPort standard and the
generic framework now provides a helper to switch between them, which
is handling the explicit disabling of non-transparent mode and its
disable->enable sequence mentioned in the DP Standard v2.0 section
3.6.6.1.

So use the new drm generic helper instead as it makes the code a bit
cleaner.

Acked-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
---
 .../gpu/drm/i915/display/intel_dp_link_training.c  | 24 +++++-----------------
 1 file changed, 5 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
index 8b1977cfec503c70f07af716ee2c00e7605c6adf..c5bad311edf7b9a5cebb633b9e9692bae397f9ed 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
@@ -119,9 +119,6 @@ intel_dp_set_lttpr_transparent_mode(struct intel_dp *intel_dp, bool enable)
 	u8 val = enable ? DP_PHY_REPEATER_MODE_TRANSPARENT :
 			  DP_PHY_REPEATER_MODE_NON_TRANSPARENT;
 
-	if (drm_dp_dpcd_write(&intel_dp->aux, DP_PHY_REPEATER_MODE, &val, 1) != 1)
-		return false;
-
 	intel_dp->lttpr_common_caps[DP_PHY_REPEATER_MODE -
 				    DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV] = val;
 
@@ -146,6 +143,7 @@ static bool intel_dp_lttpr_transparent_mode_enabled(struct intel_dp *intel_dp)
 static int intel_dp_init_lttpr_phys(struct intel_dp *intel_dp, const u8 dpcd[DP_RECEIVER_CAP_SIZE])
 {
 	int lttpr_count;
+	int ret;
 
 	if (!intel_dp_read_lttpr_common_caps(intel_dp, dpcd))
 		return 0;
@@ -172,22 +170,8 @@ static int intel_dp_init_lttpr_phys(struct intel_dp *intel_dp, const u8 dpcd[DP_
 		return lttpr_count;
 	}
 
-	/*
-	 * See DP Standard v2.0 3.6.6.1. about the explicit disabling of
-	 * non-transparent mode and the disable->enable non-transparent mode
-	 * sequence.
-	 */
-	intel_dp_set_lttpr_transparent_mode(intel_dp, true);
-
-	/*
-	 * In case of unsupported number of LTTPRs or failing to switch to
-	 * non-transparent mode fall-back to transparent link training mode,
-	 * still taking into account any LTTPR common lane- rate/count limits.
-	 */
-	if (lttpr_count < 0)
-		goto out_reset_lttpr_count;
-
-	if (!intel_dp_set_lttpr_transparent_mode(intel_dp, false)) {
+	ret = drm_dp_lttpr_init(&intel_dp->aux, lttpr_count);
+	if (ret) {
 		lt_dbg(intel_dp, DP_PHY_DPRX,
 		       "Switching to LTTPR non-transparent LT mode failed, fall-back to transparent mode\n");
 
@@ -196,6 +180,8 @@ static int intel_dp_init_lttpr_phys(struct intel_dp *intel_dp, const u8 dpcd[DP_
 		goto out_reset_lttpr_count;
 	}
 
+	intel_dp_set_lttpr_transparent_mode(intel_dp, false);
+
 	return lttpr_count;
 
 out_reset_lttpr_count:

-- 
2.34.1
Re: [PATCH v3 3/4] drm/i915/dp: Use the generic helper to control LTTPR transparent mode
Posted by Dmitry Baryshkov 1 year, 1 month ago 
On Fri, Jan 03, 2025 at 02:58:17PM +0200, Abel Vesa wrote:
> LTTPRs operating modes are defined by the DisplayPort standard and the
> generic framework now provides a helper to switch between them, which
> is handling the explicit disabling of non-transparent mode and its
> disable->enable sequence mentioned in the DP Standard v2.0 section
> 3.6.6.1.
> 
> So use the new drm generic helper instead as it makes the code a bit
> cleaner.
> 
> Acked-by: Imre Deak <imre.deak@intel.com>
> Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
> ---
>  .../gpu/drm/i915/display/intel_dp_link_training.c  | 24 +++++-----------------
>  1 file changed, 5 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> index 8b1977cfec503c70f07af716ee2c00e7605c6adf..c5bad311edf7b9a5cebb633b9e9692bae397f9ed 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> @@ -119,9 +119,6 @@ intel_dp_set_lttpr_transparent_mode(struct intel_dp *intel_dp, bool enable)
>  	u8 val = enable ? DP_PHY_REPEATER_MODE_TRANSPARENT :
>  			  DP_PHY_REPEATER_MODE_NON_TRANSPARENT;
>  
> -	if (drm_dp_dpcd_write(&intel_dp->aux, DP_PHY_REPEATER_MODE, &val, 1) != 1)
> -		return false;
> -
>  	intel_dp->lttpr_common_caps[DP_PHY_REPEATER_MODE -
>  				    DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV] = val;
>  
> @@ -146,6 +143,7 @@ static bool intel_dp_lttpr_transparent_mode_enabled(struct intel_dp *intel_dp)
>  static int intel_dp_init_lttpr_phys(struct intel_dp *intel_dp, const u8 dpcd[DP_RECEIVER_CAP_SIZE])
>  {
>  	int lttpr_count;
> +	int ret;
>  
>  	if (!intel_dp_read_lttpr_common_caps(intel_dp, dpcd))
>  		return 0;
> @@ -172,22 +170,8 @@ static int intel_dp_init_lttpr_phys(struct intel_dp *intel_dp, const u8 dpcd[DP_
>  		return lttpr_count;
>  	}
>  
> -	/*
> -	 * See DP Standard v2.0 3.6.6.1. about the explicit disabling of
> -	 * non-transparent mode and the disable->enable non-transparent mode
> -	 * sequence.
> -	 */
> -	intel_dp_set_lttpr_transparent_mode(intel_dp, true);
> -
> -	/*
> -	 * In case of unsupported number of LTTPRs or failing to switch to
> -	 * non-transparent mode fall-back to transparent link training mode,
> -	 * still taking into account any LTTPR common lane- rate/count limits.
> -	 */
> -	if (lttpr_count < 0)
> -		goto out_reset_lttpr_count;
> -
> -	if (!intel_dp_set_lttpr_transparent_mode(intel_dp, false)) {
> +	ret = drm_dp_lttpr_init(&intel_dp->aux, lttpr_count);
> +	if (ret) {
>  		lt_dbg(intel_dp, DP_PHY_DPRX,
>  		       "Switching to LTTPR non-transparent LT mode failed, fall-back to transparent mode\n");
>  
> @@ -196,6 +180,8 @@ static int intel_dp_init_lttpr_phys(struct intel_dp *intel_dp, const u8 dpcd[DP_
>  		goto out_reset_lttpr_count;
>  	}
>  
> +	intel_dp_set_lttpr_transparent_mode(intel_dp, false);
> +

I think the code now misses a way to update intel_dp->lttpr_common_caps
in a transparent-mode case:
intel_dp_set_lttpr_transparent_mode(intel_dp, true).

>  	return lttpr_count;
>  
>  out_reset_lttpr_count:
> 
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry
Re: [PATCH v3 3/4] drm/i915/dp: Use the generic helper to control LTTPR transparent mode
Posted by Abel Vesa 1 year, 1 month ago 
On 25-01-03 20:09:42, Dmitry Baryshkov wrote:
> On Fri, Jan 03, 2025 at 02:58:17PM +0200, Abel Vesa wrote:
> > LTTPRs operating modes are defined by the DisplayPort standard and the
> > generic framework now provides a helper to switch between them, which
> > is handling the explicit disabling of non-transparent mode and its
> > disable->enable sequence mentioned in the DP Standard v2.0 section
> > 3.6.6.1.
> > 
> > So use the new drm generic helper instead as it makes the code a bit
> > cleaner.
> > 
> > Acked-by: Imre Deak <imre.deak@intel.com>
> > Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
> > ---
> >  .../gpu/drm/i915/display/intel_dp_link_training.c  | 24 +++++-----------------
> >  1 file changed, 5 insertions(+), 19 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> > index 8b1977cfec503c70f07af716ee2c00e7605c6adf..c5bad311edf7b9a5cebb633b9e9692bae397f9ed 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> > @@ -119,9 +119,6 @@ intel_dp_set_lttpr_transparent_mode(struct intel_dp *intel_dp, bool enable)
> >  	u8 val = enable ? DP_PHY_REPEATER_MODE_TRANSPARENT :
> >  			  DP_PHY_REPEATER_MODE_NON_TRANSPARENT;
> >  
> > -	if (drm_dp_dpcd_write(&intel_dp->aux, DP_PHY_REPEATER_MODE, &val, 1) != 1)
> > -		return false;
> > -
> >  	intel_dp->lttpr_common_caps[DP_PHY_REPEATER_MODE -
> >  				    DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV] = val;
> >  
> > @@ -146,6 +143,7 @@ static bool intel_dp_lttpr_transparent_mode_enabled(struct intel_dp *intel_dp)
> >  static int intel_dp_init_lttpr_phys(struct intel_dp *intel_dp, const u8 dpcd[DP_RECEIVER_CAP_SIZE])
> >  {
> >  	int lttpr_count;
> > +	int ret;
> >  
> >  	if (!intel_dp_read_lttpr_common_caps(intel_dp, dpcd))
> >  		return 0;
> > @@ -172,22 +170,8 @@ static int intel_dp_init_lttpr_phys(struct intel_dp *intel_dp, const u8 dpcd[DP_
> >  		return lttpr_count;
> >  	}
> >  
> > -	/*
> > -	 * See DP Standard v2.0 3.6.6.1. about the explicit disabling of
> > -	 * non-transparent mode and the disable->enable non-transparent mode
> > -	 * sequence.
> > -	 */
> > -	intel_dp_set_lttpr_transparent_mode(intel_dp, true);
> > -
> > -	/*
> > -	 * In case of unsupported number of LTTPRs or failing to switch to
> > -	 * non-transparent mode fall-back to transparent link training mode,
> > -	 * still taking into account any LTTPR common lane- rate/count limits.
> > -	 */
> > -	if (lttpr_count < 0)
> > -		goto out_reset_lttpr_count;
> > -
> > -	if (!intel_dp_set_lttpr_transparent_mode(intel_dp, false)) {
> > +	ret = drm_dp_lttpr_init(&intel_dp->aux, lttpr_count);
> > +	if (ret) {
> >  		lt_dbg(intel_dp, DP_PHY_DPRX,
> >  		       "Switching to LTTPR non-transparent LT mode failed, fall-back to transparent mode\n");
> >  
> > @@ -196,6 +180,8 @@ static int intel_dp_init_lttpr_phys(struct intel_dp *intel_dp, const u8 dpcd[DP_
> >  		goto out_reset_lttpr_count;
> >  	}
> >  
> > +	intel_dp_set_lttpr_transparent_mode(intel_dp, false);
> > +
> 
> I think the code now misses a way to update intel_dp->lttpr_common_caps
> in a transparent-mode case:
> intel_dp_set_lttpr_transparent_mode(intel_dp, true).

It is being called if the drm_dp_lttpr_init() returns a non-zero value,
but that is not part of the diff here.

> 
> >  	return lttpr_count;
> >  
> >  out_reset_lttpr_count:
> > 
> > -- 
> > 2.34.1
> > 
> 
> -- 
> With best wishes
> Dmitry
Re: [PATCH v3 3/4] drm/i915/dp: Use the generic helper to control LTTPR transparent mode
Posted by Dmitry Baryshkov 1 year, 1 month ago 
On Mon, Jan 06, 2025 at 02:45:48PM +0200, Abel Vesa wrote:
> On 25-01-03 20:09:42, Dmitry Baryshkov wrote:
> > On Fri, Jan 03, 2025 at 02:58:17PM +0200, Abel Vesa wrote:
> > > LTTPRs operating modes are defined by the DisplayPort standard and the
> > > generic framework now provides a helper to switch between them, which
> > > is handling the explicit disabling of non-transparent mode and its
> > > disable->enable sequence mentioned in the DP Standard v2.0 section
> > > 3.6.6.1.
> > > 
> > > So use the new drm generic helper instead as it makes the code a bit
> > > cleaner.
> > > 
> > > Acked-by: Imre Deak <imre.deak@intel.com>
> > > Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
> > > ---
> > >  .../gpu/drm/i915/display/intel_dp_link_training.c  | 24 +++++-----------------
> > >  1 file changed, 5 insertions(+), 19 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> > > index 8b1977cfec503c70f07af716ee2c00e7605c6adf..c5bad311edf7b9a5cebb633b9e9692bae397f9ed 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> > > @@ -119,9 +119,6 @@ intel_dp_set_lttpr_transparent_mode(struct intel_dp *intel_dp, bool enable)
> > >  	u8 val = enable ? DP_PHY_REPEATER_MODE_TRANSPARENT :
> > >  			  DP_PHY_REPEATER_MODE_NON_TRANSPARENT;
> > >  
> > > -	if (drm_dp_dpcd_write(&intel_dp->aux, DP_PHY_REPEATER_MODE, &val, 1) != 1)
> > > -		return false;
> > > -
> > >  	intel_dp->lttpr_common_caps[DP_PHY_REPEATER_MODE -
> > >  				    DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV] = val;
> > >  
> > > @@ -146,6 +143,7 @@ static bool intel_dp_lttpr_transparent_mode_enabled(struct intel_dp *intel_dp)
> > >  static int intel_dp_init_lttpr_phys(struct intel_dp *intel_dp, const u8 dpcd[DP_RECEIVER_CAP_SIZE])
> > >  {
> > >  	int lttpr_count;
> > > +	int ret;
> > >  
> > >  	if (!intel_dp_read_lttpr_common_caps(intel_dp, dpcd))
> > >  		return 0;
> > > @@ -172,22 +170,8 @@ static int intel_dp_init_lttpr_phys(struct intel_dp *intel_dp, const u8 dpcd[DP_
> > >  		return lttpr_count;
> > >  	}
> > >  
> > > -	/*
> > > -	 * See DP Standard v2.0 3.6.6.1. about the explicit disabling of
> > > -	 * non-transparent mode and the disable->enable non-transparent mode
> > > -	 * sequence.
> > > -	 */
> > > -	intel_dp_set_lttpr_transparent_mode(intel_dp, true);
> > > -
> > > -	/*
> > > -	 * In case of unsupported number of LTTPRs or failing to switch to
> > > -	 * non-transparent mode fall-back to transparent link training mode,
> > > -	 * still taking into account any LTTPR common lane- rate/count limits.
> > > -	 */
> > > -	if (lttpr_count < 0)
> > > -		goto out_reset_lttpr_count;
> > > -
> > > -	if (!intel_dp_set_lttpr_transparent_mode(intel_dp, false)) {
> > > +	ret = drm_dp_lttpr_init(&intel_dp->aux, lttpr_count);
> > > +	if (ret) {
> > >  		lt_dbg(intel_dp, DP_PHY_DPRX,
> > >  		       "Switching to LTTPR non-transparent LT mode failed, fall-back to transparent mode\n");
> > >  
> > > @@ -196,6 +180,8 @@ static int intel_dp_init_lttpr_phys(struct intel_dp *intel_dp, const u8 dpcd[DP_
> > >  		goto out_reset_lttpr_count;
> > >  	}
> > >  
> > > +	intel_dp_set_lttpr_transparent_mode(intel_dp, false);
> > > +
> > 
> > I think the code now misses a way to update intel_dp->lttpr_common_caps
> > in a transparent-mode case:
> > intel_dp_set_lttpr_transparent_mode(intel_dp, true).
> 
> It is being called if the drm_dp_lttpr_init() returns a non-zero value,
> but that is not part of the diff here.

Ack, thanks for the explanation. I'd suggest mentioning that in the
commit message.

> 
> > 
> > >  	return lttpr_count;
> > >  
> > >  out_reset_lttpr_count:
> > > 
> > > -- 
> > > 2.34.1
> > > 
> > 
> > -- 
> > With best wishes
> > Dmitry

-- 
With best wishes
Dmitry
Re: [PATCH v3 3/4] drm/i915/dp: Use the generic helper to control LTTPR transparent mode
Posted by Abel Vesa 1 year, 1 month ago 
On 25-01-08 15:11:50, Dmitry Baryshkov wrote:
> On Mon, Jan 06, 2025 at 02:45:48PM +0200, Abel Vesa wrote:
> > On 25-01-03 20:09:42, Dmitry Baryshkov wrote:
> > > On Fri, Jan 03, 2025 at 02:58:17PM +0200, Abel Vesa wrote:
> > > > LTTPRs operating modes are defined by the DisplayPort standard and the
> > > > generic framework now provides a helper to switch between them, which
> > > > is handling the explicit disabling of non-transparent mode and its
> > > > disable->enable sequence mentioned in the DP Standard v2.0 section
> > > > 3.6.6.1.
> > > > 
> > > > So use the new drm generic helper instead as it makes the code a bit
> > > > cleaner.
> > > > 
> > > > Acked-by: Imre Deak <imre.deak@intel.com>
> > > > Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
> > > > ---
> > > >  .../gpu/drm/i915/display/intel_dp_link_training.c  | 24 +++++-----------------
> > > >  1 file changed, 5 insertions(+), 19 deletions(-)
> > > > 
> > > > diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> > > > index 8b1977cfec503c70f07af716ee2c00e7605c6adf..c5bad311edf7b9a5cebb633b9e9692bae397f9ed 100644
> > > > --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> > > > +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> > > > @@ -119,9 +119,6 @@ intel_dp_set_lttpr_transparent_mode(struct intel_dp *intel_dp, bool enable)
> > > >  	u8 val = enable ? DP_PHY_REPEATER_MODE_TRANSPARENT :
> > > >  			  DP_PHY_REPEATER_MODE_NON_TRANSPARENT;
> > > >  
> > > > -	if (drm_dp_dpcd_write(&intel_dp->aux, DP_PHY_REPEATER_MODE, &val, 1) != 1)
> > > > -		return false;
> > > > -
> > > >  	intel_dp->lttpr_common_caps[DP_PHY_REPEATER_MODE -
> > > >  				    DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV] = val;
> > > >  
> > > > @@ -146,6 +143,7 @@ static bool intel_dp_lttpr_transparent_mode_enabled(struct intel_dp *intel_dp)
> > > >  static int intel_dp_init_lttpr_phys(struct intel_dp *intel_dp, const u8 dpcd[DP_RECEIVER_CAP_SIZE])
> > > >  {
> > > >  	int lttpr_count;
> > > > +	int ret;
> > > >  
> > > >  	if (!intel_dp_read_lttpr_common_caps(intel_dp, dpcd))
> > > >  		return 0;
> > > > @@ -172,22 +170,8 @@ static int intel_dp_init_lttpr_phys(struct intel_dp *intel_dp, const u8 dpcd[DP_
> > > >  		return lttpr_count;
> > > >  	}
> > > >  
> > > > -	/*
> > > > -	 * See DP Standard v2.0 3.6.6.1. about the explicit disabling of
> > > > -	 * non-transparent mode and the disable->enable non-transparent mode
> > > > -	 * sequence.
> > > > -	 */
> > > > -	intel_dp_set_lttpr_transparent_mode(intel_dp, true);
> > > > -
> > > > -	/*
> > > > -	 * In case of unsupported number of LTTPRs or failing to switch to
> > > > -	 * non-transparent mode fall-back to transparent link training mode,
> > > > -	 * still taking into account any LTTPR common lane- rate/count limits.
> > > > -	 */
> > > > -	if (lttpr_count < 0)
> > > > -		goto out_reset_lttpr_count;
> > > > -
> > > > -	if (!intel_dp_set_lttpr_transparent_mode(intel_dp, false)) {
> > > > +	ret = drm_dp_lttpr_init(&intel_dp->aux, lttpr_count);
> > > > +	if (ret) {
> > > >  		lt_dbg(intel_dp, DP_PHY_DPRX,
> > > >  		       "Switching to LTTPR non-transparent LT mode failed, fall-back to transparent mode\n");
> > > >  
> > > > @@ -196,6 +180,8 @@ static int intel_dp_init_lttpr_phys(struct intel_dp *intel_dp, const u8 dpcd[DP_
> > > >  		goto out_reset_lttpr_count;
> > > >  	}
> > > >  
> > > > +	intel_dp_set_lttpr_transparent_mode(intel_dp, false);
> > > > +
> > > 
> > > I think the code now misses a way to update intel_dp->lttpr_common_caps
> > > in a transparent-mode case:
> > > intel_dp_set_lttpr_transparent_mode(intel_dp, true).
> > 
> > It is being called if the drm_dp_lttpr_init() returns a non-zero value,
> > but that is not part of the diff here.
> 
> Ack, thanks for the explanation. I'd suggest mentioning that in the
> commit message.

Sure. Will do.

> 
> > 
> > > 
> > > >  	return lttpr_count;
> > > >  
> > > >  out_reset_lttpr_count:
> > > > 
> > > > -- 
> > > > 2.34.1
> > > > 
> > > 
> > > -- 
> > > With best wishes
> > > Dmitry
> 
> -- 
> With best wishes
> Dmitry

Thanks for reviewing!

Abel

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