[PATCH 1/4] drm/i915/gen9+: Enable hotplug detection early

[PATCH 1/4] drm/i915/gen9+: Enable hotplug detection early

[Imre Deak]

For LSPCON resume time initialization we need to sample the
corresponding pin's HPD level, but this is only available when HPD
detection is enabled. Currently we enable detection only when enabling
HPD interrupts which is too late, so bring the enabling of detection
earlier.

This is needed by the next patch.

Cc: Shashank Sharma <shashank.sharma@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: <stable@vger.kernel.org> # v4.9+
Signed-off-by: Imre Deak <imre.deak@intel.com>
---
 drivers/gpu/drm/i915/i915_irq.c | 71 +++++++++++++++++++++++++++++------------
 1 file changed, 51 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 8440d8b..6daf522 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -3142,24 +3142,33 @@ static void ibx_hpd_irq_setup(struct drm_i915_private *dev_priv)
 	I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
 }
 
+static void spt_hpd_detection_setup(struct drm_i915_private *dev_priv)
+{
+	u32 hotplug;
+
+	/* Enable digital hotplug on the PCH */
+	hotplug = I915_READ(PCH_PORT_HOTPLUG);
+	hotplug |= PORTA_HOTPLUG_ENABLE |
+		   PORTB_HOTPLUG_ENABLE |
+		   PORTC_HOTPLUG_ENABLE |
+		   PORTD_HOTPLUG_ENABLE;
+	I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
+
+	hotplug = I915_READ(PCH_PORT_HOTPLUG2);
+	hotplug |= PORTE_HOTPLUG_ENABLE;
+	I915_WRITE(PCH_PORT_HOTPLUG2, hotplug);
+}
+
 static void spt_hpd_irq_setup(struct drm_i915_private *dev_priv)
 {
-	u32 hotplug_irqs, hotplug, enabled_irqs;
+	u32 hotplug_irqs, enabled_irqs;
 
 	hotplug_irqs = SDE_HOTPLUG_MASK_SPT;
 	enabled_irqs = intel_hpd_enabled_irqs(dev_priv, hpd_spt);
 
 	ibx_display_interrupt_update(dev_priv, hotplug_irqs, enabled_irqs);
 
-	/* Enable digital hotplug on the PCH */
-	hotplug = I915_READ(PCH_PORT_HOTPLUG);
-	hotplug |= PORTD_HOTPLUG_ENABLE | PORTC_HOTPLUG_ENABLE |
-		PORTB_HOTPLUG_ENABLE | PORTA_HOTPLUG_ENABLE;
-	I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
-
-	hotplug = I915_READ(PCH_PORT_HOTPLUG2);
-	hotplug |= PORTE_HOTPLUG_ENABLE;
-	I915_WRITE(PCH_PORT_HOTPLUG2, hotplug);
+	spt_hpd_detection_setup(dev_priv);
 }
 
 static void ilk_hpd_irq_setup(struct drm_i915_private *dev_priv)
@@ -3196,18 +3205,15 @@ static void ilk_hpd_irq_setup(struct drm_i915_private *dev_priv)
 	ibx_hpd_irq_setup(dev_priv);
 }
 
-static void bxt_hpd_irq_setup(struct drm_i915_private *dev_priv)
+static void __bxt_hpd_detection_setup(struct drm_i915_private *dev_priv,
+					     u32 enabled_irqs)
 {
-	u32 hotplug_irqs, hotplug, enabled_irqs;
-
-	enabled_irqs = intel_hpd_enabled_irqs(dev_priv, hpd_bxt);
-	hotplug_irqs = BXT_DE_PORT_HOTPLUG_MASK;
-
-	bdw_update_port_irq(dev_priv, hotplug_irqs, enabled_irqs);
+	u32 hotplug;
 
 	hotplug = I915_READ(PCH_PORT_HOTPLUG);
-	hotplug |= PORTC_HOTPLUG_ENABLE | PORTB_HOTPLUG_ENABLE |
-		PORTA_HOTPLUG_ENABLE;
+	hotplug |= PORTA_HOTPLUG_ENABLE |
+		   PORTB_HOTPLUG_ENABLE |
+		   PORTC_HOTPLUG_ENABLE;
 
 	DRM_DEBUG_KMS("Invert bit setting: hp_ctl:%x hp_port:%x\n",
 		      hotplug, enabled_irqs);
@@ -3217,7 +3223,6 @@ static void bxt_hpd_irq_setup(struct drm_i915_private *dev_priv)
 	 * For BXT invert bit has to be set based on AOB design
 	 * for HPD detection logic, update it based on VBT fields.
 	 */
-
 	if ((enabled_irqs & BXT_DE_PORT_HP_DDIA) &&
 	    intel_bios_is_port_hpd_inverted(dev_priv, PORT_A))
 		hotplug |= BXT_DDIA_HPD_INVERT;
@@ -3231,6 +3236,23 @@ static void bxt_hpd_irq_setup(struct drm_i915_private *dev_priv)
 	I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
 }
 
+static void bxt_hpd_detection_setup(struct drm_i915_private *dev_priv)
+{
+	__bxt_hpd_detection_setup(dev_priv, BXT_DE_PORT_HOTPLUG_MASK);
+}
+
+static void bxt_hpd_irq_setup(struct drm_i915_private *dev_priv)
+{
+	u32 hotplug_irqs, enabled_irqs;
+
+	enabled_irqs = intel_hpd_enabled_irqs(dev_priv, hpd_bxt);
+	hotplug_irqs = BXT_DE_PORT_HOTPLUG_MASK;
+
+	bdw_update_port_irq(dev_priv, hotplug_irqs, enabled_irqs);
+
+	__bxt_hpd_detection_setup(dev_priv, enabled_irqs);
+}
+
 static void ibx_irq_postinstall(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = to_i915(dev);
@@ -3246,6 +3268,12 @@ static void ibx_irq_postinstall(struct drm_device *dev)
 
 	gen5_assert_iir_is_zero(dev_priv, SDEIIR);
 	I915_WRITE(SDEIMR, ~mask);
+
+	if (HAS_PCH_IBX(dev_priv) || HAS_PCH_CPT(dev_priv) ||
+	    HAS_PCH_LPT(dev_priv))
+		; /* TODO: Enable HPD detection on older PCH platforms too */
+	else
+		spt_hpd_detection_setup(dev_priv);
 }
 
 static void gen5_gt_irq_postinstall(struct drm_device *dev)
@@ -3457,6 +3485,9 @@ static void gen8_de_irq_postinstall(struct drm_i915_private *dev_priv)
 
 	GEN5_IRQ_INIT(GEN8_DE_PORT_, ~de_port_masked, de_port_enables);
 	GEN5_IRQ_INIT(GEN8_DE_MISC_, ~de_misc_masked, de_misc_masked);
+
+	if (IS_GEN9_LP(dev_priv))
+		bxt_hpd_detection_setup(dev_priv);
 }
 
 static int gen8_irq_postinstall(struct drm_device *dev)
-- 
2.5.0

[PATCH 2/4] drm/i915/lspcon: Fix resume time initialization due to unasserted HPD

[Imre Deak]

During system resume time initialization the HPD level on LSPCON ports
can stay low for an extended amount of time, leading to failed AUX
transfers and LSPCON initialization. Fix this by waiting for HPD to get
asserted.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99178
Cc: Shashank Sharma <shashank.sharma@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: <stable@vger.kernel.org> # v4.9+
Signed-off-by: Imre Deak <imre.deak@intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c     | 4 ++--
 drivers/gpu/drm/i915/intel_drv.h    | 2 ++
 drivers/gpu/drm/i915/intel_lspcon.c | 5 ++++-
 3 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index e0f9b9e..a7785ce 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4400,8 +4400,8 @@ static bool bxt_digital_port_connected(struct drm_i915_private *dev_priv,
  *
  * Return %true if @port is connected, %false otherwise.
  */
-static bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
-					 struct intel_digital_port *port)
+bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
+				  struct intel_digital_port *port)
 {
 	if (HAS_PCH_IBX(dev_priv))
 		return ibx_digital_port_connected(dev_priv, port);
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index b71fece..b9cde11 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1489,6 +1489,8 @@ bool __intel_dp_read_desc(struct intel_dp *intel_dp,
 bool intel_dp_read_desc(struct intel_dp *intel_dp);
 int intel_dp_link_required(int pixel_clock, int bpp);
 int intel_dp_max_data_rate(int max_link_clock, int max_lanes);
+bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
+				  struct intel_digital_port *port);
 
 /* intel_dp_aux_backlight.c */
 int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector);
diff --git a/drivers/gpu/drm/i915/intel_lspcon.c b/drivers/gpu/drm/i915/intel_lspcon.c
index f6d4e69..c300647 100644
--- a/drivers/gpu/drm/i915/intel_lspcon.c
+++ b/drivers/gpu/drm/i915/intel_lspcon.c
@@ -158,6 +158,8 @@ static bool lspcon_probe(struct intel_lspcon *lspcon)
 static void lspcon_resume_in_pcon_wa(struct intel_lspcon *lspcon)
 {
 	struct intel_dp *intel_dp = lspcon_to_intel_dp(lspcon);
+	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
+	struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
 	unsigned long start = jiffies;
 
 	if (!lspcon->desc_valid)
@@ -173,7 +175,8 @@ static void lspcon_resume_in_pcon_wa(struct intel_lspcon *lspcon)
 		if (!__intel_dp_read_desc(intel_dp, &desc))
 			return;
 
-		if (!memcmp(&intel_dp->desc, &desc, sizeof(desc))) {
+		if (intel_digital_port_connected(dev_priv, dig_port) &&
+		    !memcmp(&intel_dp->desc, &desc, sizeof(desc))) {
 			DRM_DEBUG_KMS("LSPCON recovering in PCON mode after %u ms\n",
 				      jiffies_to_msecs(jiffies - start));
 			return;
-- 
2.5.0

Re: [PATCH 1/4] drm/i915/gen9+: Enable hotplug detection early

[Sharma, Shashank]

Regards

Shashank


On 1/27/2017 3:09 PM, Imre Deak wrote:
> For LSPCON resume time initialization we need to sample the
> corresponding pin's HPD level, but this is only available when HPD
> detection is enabled. Currently we enable detection only when enabling
> HPD interrupts which is too late, so bring the enabling of detection
> earlier.
>
> This is needed by the next patch.
>
> Cc: Shashank Sharma <shashank.sharma@intel.com>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: <stable@vger.kernel.org> # v4.9+
> Signed-off-by: Imre Deak <imre.deak@intel.com>
> ---
>   drivers/gpu/drm/i915/i915_irq.c | 71 +++++++++++++++++++++++++++++------------
>   1 file changed, 51 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index 8440d8b..6daf522 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -3142,24 +3142,33 @@ static void ibx_hpd_irq_setup(struct drm_i915_private *dev_priv)
>   	I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
>   }
>   
> +static void spt_hpd_detection_setup(struct drm_i915_private *dev_priv)
> +{
> +	u32 hotplug;
> +
> +	/* Enable digital hotplug on the PCH */
> +	hotplug = I915_READ(PCH_PORT_HOTPLUG);
> +	hotplug |= PORTA_HOTPLUG_ENABLE |
> +		   PORTB_HOTPLUG_ENABLE |
> +		   PORTC_HOTPLUG_ENABLE |
> +		   PORTD_HOTPLUG_ENABLE;
> +	I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
> +
> +	hotplug = I915_READ(PCH_PORT_HOTPLUG2);
> +	hotplug |= PORTE_HOTPLUG_ENABLE;
> +	I915_WRITE(PCH_PORT_HOTPLUG2, hotplug);
> +}
> +
>   static void spt_hpd_irq_setup(struct drm_i915_private *dev_priv)
>   {
> -	u32 hotplug_irqs, hotplug, enabled_irqs;
> +	u32 hotplug_irqs, enabled_irqs;
>   
>   	hotplug_irqs = SDE_HOTPLUG_MASK_SPT;
>   	enabled_irqs = intel_hpd_enabled_irqs(dev_priv, hpd_spt);
>   
>   	ibx_display_interrupt_update(dev_priv, hotplug_irqs, enabled_irqs);
>   
> -	/* Enable digital hotplug on the PCH */
> -	hotplug = I915_READ(PCH_PORT_HOTPLUG);
> -	hotplug |= PORTD_HOTPLUG_ENABLE | PORTC_HOTPLUG_ENABLE |
> -		PORTB_HOTPLUG_ENABLE | PORTA_HOTPLUG_ENABLE;
> -	I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
> -
> -	hotplug = I915_READ(PCH_PORT_HOTPLUG2);
> -	hotplug |= PORTE_HOTPLUG_ENABLE;
> -	I915_WRITE(PCH_PORT_HOTPLUG2, hotplug);
> +	spt_hpd_detection_setup(dev_priv);
>   }
>   
>   static void ilk_hpd_irq_setup(struct drm_i915_private *dev_priv)
> @@ -3196,18 +3205,15 @@ static void ilk_hpd_irq_setup(struct drm_i915_private *dev_priv)
>   	ibx_hpd_irq_setup(dev_priv);
>   }
>   
> -static void bxt_hpd_irq_setup(struct drm_i915_private *dev_priv)
> +static void __bxt_hpd_detection_setup(struct drm_i915_private *dev_priv,
> +					     u32 enabled_irqs)
>   {
> -	u32 hotplug_irqs, hotplug, enabled_irqs;
> -
> -	enabled_irqs = intel_hpd_enabled_irqs(dev_priv, hpd_bxt);
> -	hotplug_irqs = BXT_DE_PORT_HOTPLUG_MASK;
> -
> -	bdw_update_port_irq(dev_priv, hotplug_irqs, enabled_irqs);
> +	u32 hotplug;
>   
>   	hotplug = I915_READ(PCH_PORT_HOTPLUG);
> -	hotplug |= PORTC_HOTPLUG_ENABLE | PORTB_HOTPLUG_ENABLE |
> -		PORTA_HOTPLUG_ENABLE;
> +	hotplug |= PORTA_HOTPLUG_ENABLE |
> +		   PORTB_HOTPLUG_ENABLE |
> +		   PORTC_HOTPLUG_ENABLE;
>   
>   	DRM_DEBUG_KMS("Invert bit setting: hp_ctl:%x hp_port:%x\n",
>   		      hotplug, enabled_irqs);
> @@ -3217,7 +3223,6 @@ static void bxt_hpd_irq_setup(struct drm_i915_private *dev_priv)
>   	 * For BXT invert bit has to be set based on AOB design
>   	 * for HPD detection logic, update it based on VBT fields.
>   	 */
> -
>   	if ((enabled_irqs & BXT_DE_PORT_HP_DDIA) &&
>   	    intel_bios_is_port_hpd_inverted(dev_priv, PORT_A))
>   		hotplug |= BXT_DDIA_HPD_INVERT;
> @@ -3231,6 +3236,23 @@ static void bxt_hpd_irq_setup(struct drm_i915_private *dev_priv)
>   	I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
>   }
>   
> +static void bxt_hpd_detection_setup(struct drm_i915_private *dev_priv)
> +{
> +	__bxt_hpd_detection_setup(dev_priv, BXT_DE_PORT_HOTPLUG_MASK);
Do we need another layer of internal function ? Why cant the content of 
__bxt_hpd_detection_setup be here, just
like spd_hpd_detection_setup, as they both are static to the file ?
> +}
> +
> +static void bxt_hpd_irq_setup(struct drm_i915_private *dev_priv)
> +{
> +	u32 hotplug_irqs, enabled_irqs;
> +
> +	enabled_irqs = intel_hpd_enabled_irqs(dev_priv, hpd_bxt);
> +	hotplug_irqs = BXT_DE_PORT_HOTPLUG_MASK;
> +
> +	bdw_update_port_irq(dev_priv, hotplug_irqs, enabled_irqs);
> +
> +	__bxt_hpd_detection_setup(dev_priv, enabled_irqs);
> +}
> +
>   static void ibx_irq_postinstall(struct drm_device *dev)
>   {
>   	struct drm_i915_private *dev_priv = to_i915(dev);
> @@ -3246,6 +3268,12 @@ static void ibx_irq_postinstall(struct drm_device *dev)
>   
>   	gen5_assert_iir_is_zero(dev_priv, SDEIIR);
>   	I915_WRITE(SDEIMR, ~mask);
> +
> +	if (HAS_PCH_IBX(dev_priv) || HAS_PCH_CPT(dev_priv) ||
> +	    HAS_PCH_LPT(dev_priv))
> +		; /* TODO: Enable HPD detection on older PCH platforms too */
> +	else
> +		spt_hpd_detection_setup(dev_priv);
>   }
>   
>   static void gen5_gt_irq_postinstall(struct drm_device *dev)
> @@ -3457,6 +3485,9 @@ static void gen8_de_irq_postinstall(struct drm_i915_private *dev_priv)
>   
>   	GEN5_IRQ_INIT(GEN8_DE_PORT_, ~de_port_masked, de_port_enables);
>   	GEN5_IRQ_INIT(GEN8_DE_MISC_, ~de_misc_masked, de_misc_masked);
> +
> +	if (IS_GEN9_LP(dev_priv))
I have not done the delta analysis between hotplug interrupts, but this 
will be true for GLK too.
Should we bother ?

- Shashank
> +		bxt_hpd_detection_setup(dev_priv);
>   }
>   
>   static int gen8_irq_postinstall(struct drm_device *dev)

Re: [PATCH 2/4] drm/i915/lspcon: Fix resume time initialization due to unasserted HPD

[Sharma, Shashank]

Regards

Shashank


On 1/27/2017 3:09 PM, Imre Deak wrote:
> During system resume time initialization the HPD level on LSPCON ports
> can stay low for an extended amount of time, leading to failed AUX
> transfers and LSPCON initialization. Fix this by waiting for HPD to get
> asserted.
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99178
> Cc: Shashank Sharma <shashank.sharma@intel.com>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: <stable@vger.kernel.org> # v4.9+
> Signed-off-by: Imre Deak <imre.deak@intel.com>
> ---
>   drivers/gpu/drm/i915/intel_dp.c     | 4 ++--
>   drivers/gpu/drm/i915/intel_drv.h    | 2 ++
>   drivers/gpu/drm/i915/intel_lspcon.c | 5 ++++-
>   3 files changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index e0f9b9e..a7785ce 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -4400,8 +4400,8 @@ static bool bxt_digital_port_connected(struct drm_i915_private *dev_priv,
>    *
>    * Return %true if @port is connected, %false otherwise.
>    */
> -static bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
> -					 struct intel_digital_port *port)
> +bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
> +				  struct intel_digital_port *port)
>   {
>   	if (HAS_PCH_IBX(dev_priv))
>   		return ibx_digital_port_connected(dev_priv, port);
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index b71fece..b9cde11 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1489,6 +1489,8 @@ bool __intel_dp_read_desc(struct intel_dp *intel_dp,
>   bool intel_dp_read_desc(struct intel_dp *intel_dp);
>   int intel_dp_link_required(int pixel_clock, int bpp);
>   int intel_dp_max_data_rate(int max_link_clock, int max_lanes);
> +bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
> +				  struct intel_digital_port *port);
>   
>   /* intel_dp_aux_backlight.c */
>   int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector);
> diff --git a/drivers/gpu/drm/i915/intel_lspcon.c b/drivers/gpu/drm/i915/intel_lspcon.c
> index f6d4e69..c300647 100644
> --- a/drivers/gpu/drm/i915/intel_lspcon.c
> +++ b/drivers/gpu/drm/i915/intel_lspcon.c
> @@ -158,6 +158,8 @@ static bool lspcon_probe(struct intel_lspcon *lspcon)
>   static void lspcon_resume_in_pcon_wa(struct intel_lspcon *lspcon)
>   {
>   	struct intel_dp *intel_dp = lspcon_to_intel_dp(lspcon);
> +	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
> +	struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
>   	unsigned long start = jiffies;
>   
>   	if (!lspcon->desc_valid)
> @@ -173,7 +175,8 @@ static void lspcon_resume_in_pcon_wa(struct intel_lspcon *lspcon)
>   		if (!__intel_dp_read_desc(intel_dp, &desc))
>   			return;
>   
> -		if (!memcmp(&intel_dp->desc, &desc, sizeof(desc))) {
> +		if (intel_digital_port_connected(dev_priv, dig_port) &&
when in PCON mode, live_status is always up for LSPCON port, so this 
check will be always true, isn't it ?
- Shashank
> +		    !memcmp(&intel_dp->desc, &desc, sizeof(desc))) {
>   			DRM_DEBUG_KMS("LSPCON recovering in PCON mode after %u ms\n",
>   				      jiffies_to_msecs(jiffies - start));
>   			return;

Re: [PATCH 1/4] drm/i915/gen9+: Enable hotplug detection early

[Imre Deak]

On Sat, Jan 28, 2017 at 10:24:19AM +0530, Sharma, Shashank wrote:
> Regards
> 
> Shashank
> 
> 
> On 1/27/2017 3:09 PM, Imre Deak wrote:
> >For LSPCON resume time initialization we need to sample the
> >corresponding pin's HPD level, but this is only available when HPD
> >detection is enabled. Currently we enable detection only when enabling
> >HPD interrupts which is too late, so bring the enabling of detection
> >earlier.
> >
> >This is needed by the next patch.
> >
> >Cc: Shashank Sharma <shashank.sharma@intel.com>
> >Cc: Jani Nikula <jani.nikula@linux.intel.com>
> >Cc: Ville Syrj�l� <ville.syrjala@linux.intel.com>
> >Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> >Cc: <stable@vger.kernel.org> # v4.9+
> >Signed-off-by: Imre Deak <imre.deak@intel.com>
> >---
> >  drivers/gpu/drm/i915/i915_irq.c | 71 +++++++++++++++++++++++++++++------------
> >  1 file changed, 51 insertions(+), 20 deletions(-)
> >
> >diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> >index 8440d8b..6daf522 100644
> >--- a/drivers/gpu/drm/i915/i915_irq.c
> >+++ b/drivers/gpu/drm/i915/i915_irq.c
> >@@ -3142,24 +3142,33 @@ static void ibx_hpd_irq_setup(struct drm_i915_private *dev_priv)
> >  	I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
> >  }
> >+static void spt_hpd_detection_setup(struct drm_i915_private *dev_priv)
> >+{
> >+	u32 hotplug;
> >+
> >+	/* Enable digital hotplug on the PCH */
> >+	hotplug = I915_READ(PCH_PORT_HOTPLUG);
> >+	hotplug |= PORTA_HOTPLUG_ENABLE |
> >+		   PORTB_HOTPLUG_ENABLE |
> >+		   PORTC_HOTPLUG_ENABLE |
> >+		   PORTD_HOTPLUG_ENABLE;
> >+	I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
> >+
> >+	hotplug = I915_READ(PCH_PORT_HOTPLUG2);
> >+	hotplug |= PORTE_HOTPLUG_ENABLE;
> >+	I915_WRITE(PCH_PORT_HOTPLUG2, hotplug);
> >+}
> >+
> >  static void spt_hpd_irq_setup(struct drm_i915_private *dev_priv)
> >  {
> >-	u32 hotplug_irqs, hotplug, enabled_irqs;
> >+	u32 hotplug_irqs, enabled_irqs;
> >  	hotplug_irqs = SDE_HOTPLUG_MASK_SPT;
> >  	enabled_irqs = intel_hpd_enabled_irqs(dev_priv, hpd_spt);
> >  	ibx_display_interrupt_update(dev_priv, hotplug_irqs, enabled_irqs);
> >-	/* Enable digital hotplug on the PCH */
> >-	hotplug = I915_READ(PCH_PORT_HOTPLUG);
> >-	hotplug |= PORTD_HOTPLUG_ENABLE | PORTC_HOTPLUG_ENABLE |
> >-		PORTB_HOTPLUG_ENABLE | PORTA_HOTPLUG_ENABLE;
> >-	I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
> >-
> >-	hotplug = I915_READ(PCH_PORT_HOTPLUG2);
> >-	hotplug |= PORTE_HOTPLUG_ENABLE;
> >-	I915_WRITE(PCH_PORT_HOTPLUG2, hotplug);
> >+	spt_hpd_detection_setup(dev_priv);
> >  }
> >  static void ilk_hpd_irq_setup(struct drm_i915_private *dev_priv)
> >@@ -3196,18 +3205,15 @@ static void ilk_hpd_irq_setup(struct drm_i915_private *dev_priv)
> >  	ibx_hpd_irq_setup(dev_priv);
> >  }
> >-static void bxt_hpd_irq_setup(struct drm_i915_private *dev_priv)
> >+static void __bxt_hpd_detection_setup(struct drm_i915_private *dev_priv,
> >+					     u32 enabled_irqs)
> >  {
> >-	u32 hotplug_irqs, hotplug, enabled_irqs;
> >-
> >-	enabled_irqs = intel_hpd_enabled_irqs(dev_priv, hpd_bxt);
> >-	hotplug_irqs = BXT_DE_PORT_HOTPLUG_MASK;
> >-
> >-	bdw_update_port_irq(dev_priv, hotplug_irqs, enabled_irqs);
> >+	u32 hotplug;
> >  	hotplug = I915_READ(PCH_PORT_HOTPLUG);
> >-	hotplug |= PORTC_HOTPLUG_ENABLE | PORTB_HOTPLUG_ENABLE |
> >-		PORTA_HOTPLUG_ENABLE;
> >+	hotplug |= PORTA_HOTPLUG_ENABLE |
> >+		   PORTB_HOTPLUG_ENABLE |
> >+		   PORTC_HOTPLUG_ENABLE;
> >  	DRM_DEBUG_KMS("Invert bit setting: hp_ctl:%x hp_port:%x\n",
> >  		      hotplug, enabled_irqs);
> >@@ -3217,7 +3223,6 @@ static void bxt_hpd_irq_setup(struct drm_i915_private *dev_priv)
> >  	 * For BXT invert bit has to be set based on AOB design
> >  	 * for HPD detection logic, update it based on VBT fields.
> >  	 */
> >-
> >  	if ((enabled_irqs & BXT_DE_PORT_HP_DDIA) &&
> >  	    intel_bios_is_port_hpd_inverted(dev_priv, PORT_A))
> >  		hotplug |= BXT_DDIA_HPD_INVERT;
> >@@ -3231,6 +3236,23 @@ static void bxt_hpd_irq_setup(struct drm_i915_private *dev_priv)
> >  	I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
> >  }
> >+static void bxt_hpd_detection_setup(struct drm_i915_private *dev_priv)
> >+{
> >+	__bxt_hpd_detection_setup(dev_priv, BXT_DE_PORT_HOTPLUG_MASK);
> Do we need another layer of internal function ? Why cant the content of
> __bxt_hpd_detection_setup be here, just
> like spd_hpd_detection_setup, as they both are static to the file ?

The port configuration is platform specific and so I wanted to keep it
close to where the rest of HPD setup is done. The caller of
bxt_hpd_detection_setup() only cares about enabling detection on _all_
ports as the other *_hpd_detection_setup() helpers.

> >+}
> >+
> >+static void bxt_hpd_irq_setup(struct drm_i915_private *dev_priv)
> >+{
> >+	u32 hotplug_irqs, enabled_irqs;
> >+
> >+	enabled_irqs = intel_hpd_enabled_irqs(dev_priv, hpd_bxt);
> >+	hotplug_irqs = BXT_DE_PORT_HOTPLUG_MASK;
> >+
> >+	bdw_update_port_irq(dev_priv, hotplug_irqs, enabled_irqs);
> >+
> >+	__bxt_hpd_detection_setup(dev_priv, enabled_irqs);
> >+}
> >+
> >  static void ibx_irq_postinstall(struct drm_device *dev)
> >  {
> >  	struct drm_i915_private *dev_priv = to_i915(dev);
> >@@ -3246,6 +3268,12 @@ static void ibx_irq_postinstall(struct drm_device *dev)
> >  	gen5_assert_iir_is_zero(dev_priv, SDEIIR);
> >  	I915_WRITE(SDEIMR, ~mask);
> >+
> >+	if (HAS_PCH_IBX(dev_priv) || HAS_PCH_CPT(dev_priv) ||
> >+	    HAS_PCH_LPT(dev_priv))
> >+		; /* TODO: Enable HPD detection on older PCH platforms too */
> >+	else
> >+		spt_hpd_detection_setup(dev_priv);
> >  }
> >  static void gen5_gt_irq_postinstall(struct drm_device *dev)
> >@@ -3457,6 +3485,9 @@ static void gen8_de_irq_postinstall(struct drm_i915_private *dev_priv)
> >  	GEN5_IRQ_INIT(GEN8_DE_PORT_, ~de_port_masked, de_port_enables);
> >  	GEN5_IRQ_INIT(GEN8_DE_MISC_, ~de_misc_masked, de_misc_masked);
> >+
> >+	if (IS_GEN9_LP(dev_priv))
> I have not done the delta analysis between hotplug interrupts, but this will
> be true for GLK too.
> Should we bother ?

The GLK HPD detection setup and interrupt setup and handling is the same as
on BXT. See bxt_hpd_irq_setup() and bxt_hpd_irq_handler() that are
called on GLK as well.

> 
> - Shashank
> >+		bxt_hpd_detection_setup(dev_priv);
> >  }
> >  static int gen8_irq_postinstall(struct drm_device *dev)
> 

Re: [PATCH 2/4] drm/i915/lspcon: Fix resume time initialization due to unasserted HPD

[Imre Deak]

On Sat, Jan 28, 2017 at 10:32:03AM +0530, Sharma, Shashank wrote:
> Regards
> 
> Shashank
> 
> 
> On 1/27/2017 3:09 PM, Imre Deak wrote:
> >During system resume time initialization the HPD level on LSPCON ports
> >can stay low for an extended amount of time, leading to failed AUX
> >transfers and LSPCON initialization. Fix this by waiting for HPD to get
> >asserted.
> >
> >Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99178
> >Cc: Shashank Sharma <shashank.sharma@intel.com>
> >Cc: Jani Nikula <jani.nikula@linux.intel.com>
> >Cc: Ville Syrj�l� <ville.syrjala@linux.intel.com>
> >Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> >Cc: <stable@vger.kernel.org> # v4.9+
> >Signed-off-by: Imre Deak <imre.deak@intel.com>
> >---
> >  drivers/gpu/drm/i915/intel_dp.c     | 4 ++--
> >  drivers/gpu/drm/i915/intel_drv.h    | 2 ++
> >  drivers/gpu/drm/i915/intel_lspcon.c | 5 ++++-
> >  3 files changed, 8 insertions(+), 3 deletions(-)
> >
> >diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> >index e0f9b9e..a7785ce 100644
> >--- a/drivers/gpu/drm/i915/intel_dp.c
> >+++ b/drivers/gpu/drm/i915/intel_dp.c
> >@@ -4400,8 +4400,8 @@ static bool bxt_digital_port_connected(struct drm_i915_private *dev_priv,
> >   *
> >   * Return %true if @port is connected, %false otherwise.
> >   */
> >-static bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
> >-					 struct intel_digital_port *port)
> >+bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
> >+				  struct intel_digital_port *port)
> >  {
> >  	if (HAS_PCH_IBX(dev_priv))
> >  		return ibx_digital_port_connected(dev_priv, port);
> >diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> >index b71fece..b9cde11 100644
> >--- a/drivers/gpu/drm/i915/intel_drv.h
> >+++ b/drivers/gpu/drm/i915/intel_drv.h
> >@@ -1489,6 +1489,8 @@ bool __intel_dp_read_desc(struct intel_dp *intel_dp,
> >  bool intel_dp_read_desc(struct intel_dp *intel_dp);
> >  int intel_dp_link_required(int pixel_clock, int bpp);
> >  int intel_dp_max_data_rate(int max_link_clock, int max_lanes);
> >+bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
> >+				  struct intel_digital_port *port);
> >  /* intel_dp_aux_backlight.c */
> >  int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector);
> >diff --git a/drivers/gpu/drm/i915/intel_lspcon.c b/drivers/gpu/drm/i915/intel_lspcon.c
> >index f6d4e69..c300647 100644
> >--- a/drivers/gpu/drm/i915/intel_lspcon.c
> >+++ b/drivers/gpu/drm/i915/intel_lspcon.c
> >@@ -158,6 +158,8 @@ static bool lspcon_probe(struct intel_lspcon *lspcon)
> >  static void lspcon_resume_in_pcon_wa(struct intel_lspcon *lspcon)
> >  {
> >  	struct intel_dp *intel_dp = lspcon_to_intel_dp(lspcon);
> >+	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
> >+	struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
> >  	unsigned long start = jiffies;
> >  	if (!lspcon->desc_valid)
> >@@ -173,7 +175,8 @@ static void lspcon_resume_in_pcon_wa(struct intel_lspcon *lspcon)
> >  		if (!__intel_dp_read_desc(intel_dp, &desc))
> >  			return;
> >-		if (!memcmp(&intel_dp->desc, &desc, sizeof(desc))) {
> >+		if (intel_digital_port_connected(dev_priv, dig_port) &&
> when in PCON mode, live_status is always up for LSPCON port, so this check
> will be always true, isn't it ?

Not at least in case of the MegaChips LSPCON I've seen, there it takes a
while for HPD to get asserted. And while it's not asserted AUX
transactions will either:
- return garbage in case of native AUX transactions
- hang the chip/FW until next cold reboot in case of I2C-over-AUX
  transactions
- simply not get a reply if the chip/FW initialization has reached a
  certain phase

Based on the DP specification the sink/branch device is not required to
respond in case the HPD is not asserted, so the 3rd scenario is
compliant, but the first two are not.

In PCON mode after initialization and HPD getting asserted, HPD will
stay asserted except for the short pulses signaling an output
connect/disconnect.

--Imre

> - Shashank
> >+		    !memcmp(&intel_dp->desc, &desc, sizeof(desc))) {
> >  			DRM_DEBUG_KMS("LSPCON recovering in PCON mode after %u ms\n",
> >  				      jiffies_to_msecs(jiffies - start));
> >  			return;
> 

Re: [PATCH 1/4] drm/i915/gen9+: Enable hotplug detection early

[Sharma, Shashank]

Regards

Shashank


On 1/28/2017 1:24 PM, Imre Deak wrote:
> On Sat, Jan 28, 2017 at 10:24:19AM +0530, Sharma, Shashank wrote:
>> Regards
>>
>> Shashank
>>
>>
>> On 1/27/2017 3:09 PM, Imre Deak wrote:
>>> For LSPCON resume time initialization we need to sample the
>>> corresponding pin's HPD level, but this is only available when HPD
>>> detection is enabled. Currently we enable detection only when enabling
>>> HPD interrupts which is too late, so bring the enabling of detection
>>> earlier.
>>>
>>> This is needed by the next patch.
>>>
>>> Cc: Shashank Sharma <shashank.sharma@intel.com>
>>> Cc: Jani Nikula <jani.nikula@linux.intel.com>
>>> Cc: Ville Syrj�l� <ville.syrjala@linux.intel.com>
>>> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
>>> Cc: <stable@vger.kernel.org> # v4.9+
>>> Signed-off-by: Imre Deak <imre.deak@intel.com>
>>> ---
>>>   drivers/gpu/drm/i915/i915_irq.c | 71 +++++++++++++++++++++++++++++------------
>>>   1 file changed, 51 insertions(+), 20 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
>>> index 8440d8b..6daf522 100644
>>> --- a/drivers/gpu/drm/i915/i915_irq.c
>>> +++ b/drivers/gpu/drm/i915/i915_irq.c
>>> @@ -3142,24 +3142,33 @@ static void ibx_hpd_irq_setup(struct drm_i915_private *dev_priv)
>>>   	I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
>>>   }
>>> +static void spt_hpd_detection_setup(struct drm_i915_private *dev_priv)
>>> +{
>>> +	u32 hotplug;
>>> +
>>> +	/* Enable digital hotplug on the PCH */
>>> +	hotplug = I915_READ(PCH_PORT_HOTPLUG);
>>> +	hotplug |= PORTA_HOTPLUG_ENABLE |
>>> +		   PORTB_HOTPLUG_ENABLE |
>>> +		   PORTC_HOTPLUG_ENABLE |
>>> +		   PORTD_HOTPLUG_ENABLE;
>>> +	I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
>>> +
>>> +	hotplug = I915_READ(PCH_PORT_HOTPLUG2);
>>> +	hotplug |= PORTE_HOTPLUG_ENABLE;
>>> +	I915_WRITE(PCH_PORT_HOTPLUG2, hotplug);
>>> +}
>>> +
>>>   static void spt_hpd_irq_setup(struct drm_i915_private *dev_priv)
>>>   {
>>> -	u32 hotplug_irqs, hotplug, enabled_irqs;
>>> +	u32 hotplug_irqs, enabled_irqs;
>>>   	hotplug_irqs = SDE_HOTPLUG_MASK_SPT;
>>>   	enabled_irqs = intel_hpd_enabled_irqs(dev_priv, hpd_spt);
>>>   	ibx_display_interrupt_update(dev_priv, hotplug_irqs, enabled_irqs);
>>> -	/* Enable digital hotplug on the PCH */
>>> -	hotplug = I915_READ(PCH_PORT_HOTPLUG);
>>> -	hotplug |= PORTD_HOTPLUG_ENABLE | PORTC_HOTPLUG_ENABLE |
>>> -		PORTB_HOTPLUG_ENABLE | PORTA_HOTPLUG_ENABLE;
>>> -	I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
>>> -
>>> -	hotplug = I915_READ(PCH_PORT_HOTPLUG2);
>>> -	hotplug |= PORTE_HOTPLUG_ENABLE;
>>> -	I915_WRITE(PCH_PORT_HOTPLUG2, hotplug);
>>> +	spt_hpd_detection_setup(dev_priv);
>>>   }
>>>   static void ilk_hpd_irq_setup(struct drm_i915_private *dev_priv)
>>> @@ -3196,18 +3205,15 @@ static void ilk_hpd_irq_setup(struct drm_i915_private *dev_priv)
>>>   	ibx_hpd_irq_setup(dev_priv);
>>>   }
>>> -static void bxt_hpd_irq_setup(struct drm_i915_private *dev_priv)
>>> +static void __bxt_hpd_detection_setup(struct drm_i915_private *dev_priv,
>>> +					     u32 enabled_irqs)
>>>   {
>>> -	u32 hotplug_irqs, hotplug, enabled_irqs;
>>> -
>>> -	enabled_irqs = intel_hpd_enabled_irqs(dev_priv, hpd_bxt);
>>> -	hotplug_irqs = BXT_DE_PORT_HOTPLUG_MASK;
>>> -
>>> -	bdw_update_port_irq(dev_priv, hotplug_irqs, enabled_irqs);
>>> +	u32 hotplug;
>>>   	hotplug = I915_READ(PCH_PORT_HOTPLUG);
>>> -	hotplug |= PORTC_HOTPLUG_ENABLE | PORTB_HOTPLUG_ENABLE |
>>> -		PORTA_HOTPLUG_ENABLE;
>>> +	hotplug |= PORTA_HOTPLUG_ENABLE |
>>> +		   PORTB_HOTPLUG_ENABLE |
>>> +		   PORTC_HOTPLUG_ENABLE;
>>>   	DRM_DEBUG_KMS("Invert bit setting: hp_ctl:%x hp_port:%x\n",
>>>   		      hotplug, enabled_irqs);
>>> @@ -3217,7 +3223,6 @@ static void bxt_hpd_irq_setup(struct drm_i915_private *dev_priv)
>>>   	 * For BXT invert bit has to be set based on AOB design
>>>   	 * for HPD detection logic, update it based on VBT fields.
>>>   	 */
>>> -
>>>   	if ((enabled_irqs & BXT_DE_PORT_HP_DDIA) &&
>>>   	    intel_bios_is_port_hpd_inverted(dev_priv, PORT_A))
>>>   		hotplug |= BXT_DDIA_HPD_INVERT;
>>> @@ -3231,6 +3236,23 @@ static void bxt_hpd_irq_setup(struct drm_i915_private *dev_priv)
>>>   	I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
>>>   }
>>> +static void bxt_hpd_detection_setup(struct drm_i915_private *dev_priv)
>>> +{
>>> +	__bxt_hpd_detection_setup(dev_priv, BXT_DE_PORT_HOTPLUG_MASK);
>> Do we need another layer of internal function ? Why cant the content of
>> __bxt_hpd_detection_setup be here, just
>> like spd_hpd_detection_setup, as they both are static to the file ?
> The port configuration is platform specific and so I wanted to keep it
> close to where the rest of HPD setup is done. The caller of
> bxt_hpd_detection_setup() only cares about enabling detection on _all_
> ports as the other *_hpd_detection_setup() helpers.
I am not very convinced, but seems no harm too :)
>>> +}
>>> +
>>> +static void bxt_hpd_irq_setup(struct drm_i915_private *dev_priv)
>>> +{
>>> +	u32 hotplug_irqs, enabled_irqs;
>>> +
>>> +	enabled_irqs = intel_hpd_enabled_irqs(dev_priv, hpd_bxt);
>>> +	hotplug_irqs = BXT_DE_PORT_HOTPLUG_MASK;
>>> +
>>> +	bdw_update_port_irq(dev_priv, hotplug_irqs, enabled_irqs);
>>> +
>>> +	__bxt_hpd_detection_setup(dev_priv, enabled_irqs);
>>> +}
>>> +
>>>   static void ibx_irq_postinstall(struct drm_device *dev)
>>>   {
>>>   	struct drm_i915_private *dev_priv = to_i915(dev);
>>> @@ -3246,6 +3268,12 @@ static void ibx_irq_postinstall(struct drm_device *dev)
>>>   	gen5_assert_iir_is_zero(dev_priv, SDEIIR);
>>>   	I915_WRITE(SDEIMR, ~mask);
>>> +
>>> +	if (HAS_PCH_IBX(dev_priv) || HAS_PCH_CPT(dev_priv) ||
>>> +	    HAS_PCH_LPT(dev_priv))
>>> +		; /* TODO: Enable HPD detection on older PCH platforms too */
>>> +	else
>>> +		spt_hpd_detection_setup(dev_priv);
>>>   }
>>>   static void gen5_gt_irq_postinstall(struct drm_device *dev)
>>> @@ -3457,6 +3485,9 @@ static void gen8_de_irq_postinstall(struct drm_i915_private *dev_priv)
>>>   	GEN5_IRQ_INIT(GEN8_DE_PORT_, ~de_port_masked, de_port_enables);
>>>   	GEN5_IRQ_INIT(GEN8_DE_MISC_, ~de_misc_masked, de_misc_masked);
>>> +
>>> +	if (IS_GEN9_LP(dev_priv))
>> I have not done the delta analysis between hotplug interrupts, but this will
>> be true for GLK too.
>> Should we bother ?
> The GLK HPD detection setup and interrupt setup and handling is the same as
> on BXT. See bxt_hpd_irq_setup() and bxt_hpd_irq_handler() that are
> called on GLK as well.
Yep, I was wandering about SCDC kind of interrupts, which are new in 
GLK, but probably I should
take care of it, while writing the code for that.

Reviewed-by: Shashank Sharma <shashank.sharma@intel.com>
>> - Shashank
>>> +		bxt_hpd_detection_setup(dev_priv);
>>>   }
>>>   static int gen8_irq_postinstall(struct drm_device *dev)

Re: [PATCH 2/4] drm/i915/lspcon: Fix resume time initialization due to unasserted HPD

[Sharma, Shashank]

Regards

Shashank


On 1/28/2017 1:47 PM, Imre Deak wrote:
> On Sat, Jan 28, 2017 at 10:32:03AM +0530, Sharma, Shashank wrote:
>> Regards
>>
>> Shashank
>>
>>
>> On 1/27/2017 3:09 PM, Imre Deak wrote:
>>> During system resume time initialization the HPD level on LSPCON ports
>>> can stay low for an extended amount of time, leading to failed AUX
>>> transfers and LSPCON initialization. Fix this by waiting for HPD to get
>>> asserted.
>>>
>>> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99178
>>> Cc: Shashank Sharma <shashank.sharma@intel.com>
>>> Cc: Jani Nikula <jani.nikula@linux.intel.com>
>>> Cc: Ville Syrj�l� <ville.syrjala@linux.intel.com>
>>> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
>>> Cc: <stable@vger.kernel.org> # v4.9+
>>> Signed-off-by: Imre Deak <imre.deak@intel.com>
>>> ---
>>>   drivers/gpu/drm/i915/intel_dp.c     | 4 ++--
>>>   drivers/gpu/drm/i915/intel_drv.h    | 2 ++
>>>   drivers/gpu/drm/i915/intel_lspcon.c | 5 ++++-
>>>   3 files changed, 8 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
>>> index e0f9b9e..a7785ce 100644
>>> --- a/drivers/gpu/drm/i915/intel_dp.c
>>> +++ b/drivers/gpu/drm/i915/intel_dp.c
>>> @@ -4400,8 +4400,8 @@ static bool bxt_digital_port_connected(struct drm_i915_private *dev_priv,
>>>    *
>>>    * Return %true if @port is connected, %false otherwise.
>>>    */
>>> -static bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
>>> -					 struct intel_digital_port *port)
>>> +bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
>>> +				  struct intel_digital_port *port)
>>>   {
>>>   	if (HAS_PCH_IBX(dev_priv))
>>>   		return ibx_digital_port_connected(dev_priv, port);
>>> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>>> index b71fece..b9cde11 100644
>>> --- a/drivers/gpu/drm/i915/intel_drv.h
>>> +++ b/drivers/gpu/drm/i915/intel_drv.h
>>> @@ -1489,6 +1489,8 @@ bool __intel_dp_read_desc(struct intel_dp *intel_dp,
>>>   bool intel_dp_read_desc(struct intel_dp *intel_dp);
>>>   int intel_dp_link_required(int pixel_clock, int bpp);
>>>   int intel_dp_max_data_rate(int max_link_clock, int max_lanes);
>>> +bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
>>> +				  struct intel_digital_port *port);
>>>   /* intel_dp_aux_backlight.c */
>>>   int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector);
>>> diff --git a/drivers/gpu/drm/i915/intel_lspcon.c b/drivers/gpu/drm/i915/intel_lspcon.c
>>> index f6d4e69..c300647 100644
>>> --- a/drivers/gpu/drm/i915/intel_lspcon.c
>>> +++ b/drivers/gpu/drm/i915/intel_lspcon.c
>>> @@ -158,6 +158,8 @@ static bool lspcon_probe(struct intel_lspcon *lspcon)
>>>   static void lspcon_resume_in_pcon_wa(struct intel_lspcon *lspcon)
>>>   {
>>>   	struct intel_dp *intel_dp = lspcon_to_intel_dp(lspcon);
>>> +	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
>>> +	struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
>>>   	unsigned long start = jiffies;
>>>   	if (!lspcon->desc_valid)
>>> @@ -173,7 +175,8 @@ static void lspcon_resume_in_pcon_wa(struct intel_lspcon *lspcon)
>>>   		if (!__intel_dp_read_desc(intel_dp, &desc))
>>>   			return;
>>> -		if (!memcmp(&intel_dp->desc, &desc, sizeof(desc))) {
>>> +		if (intel_digital_port_connected(dev_priv, dig_port) &&
>> when in PCON mode, live_status is always up for LSPCON port, so this check
>> will be always true, isn't it ?
> Not at least in case of the MegaChips LSPCON I've seen, there it takes a
> while for HPD to get asserted. And while it's not asserted AUX
> transactions will either:
> - return garbage in case of native AUX transactions
> - hang the chip/FW until next cold reboot in case of I2C-over-AUX
>    transactions
> - simply not get a reply if the chip/FW initialization has reached a
>    certain phase
>
> Based on the DP specification the sink/branch device is not required to
> respond in case the HPD is not asserted, so the 3rd scenario is
> compliant, but the first two are not.
>
> In PCON mode after initialization and HPD getting asserted, HPD will
> stay asserted except for the short pulses signaling an output
> connect/disconnect.
The reason might be, that LSPCON resumes in LS type2 adapter state, 
where the live_status behavior is normal
and reflects the real HPD line, but the moment we move to PCON mode, HPD 
gets asserted low.
I know you would have tested this well, but I also want to test this 
code and logic first, before we go ahead with the patch.

Shashank
> --Imre
>
>> - Shashank
>>> +		    !memcmp(&intel_dp->desc, &desc, sizeof(desc))) {
>>>   			DRM_DEBUG_KMS("LSPCON recovering in PCON mode after %u ms\n",
>>>   				      jiffies_to_msecs(jiffies - start));
>>>   			return;

Re: [PATCH 2/4] drm/i915/lspcon: Fix resume time initialization due to unasserted HPD

[Imre Deak]

On Sun, Jan 29, 2017 at 10:33:07AM +0530, Sharma, Shashank wrote:
> Regards
> 
> Shashank
> 
> 
> On 1/28/2017 1:47 PM, Imre Deak wrote:
> >On Sat, Jan 28, 2017 at 10:32:03AM +0530, Sharma, Shashank wrote:
> >>Regards
> >>
> >>Shashank
> >>
> >>
> >>On 1/27/2017 3:09 PM, Imre Deak wrote:
> >>>During system resume time initialization the HPD level on LSPCON ports
> >>>can stay low for an extended amount of time, leading to failed AUX
> >>>transfers and LSPCON initialization. Fix this by waiting for HPD to get
> >>>asserted.
> >>>
> >>>Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99178
> >>>Cc: Shashank Sharma <shashank.sharma@intel.com>
> >>>Cc: Jani Nikula <jani.nikula@linux.intel.com>
> >>>Cc: Ville Syrj�l� <ville.syrjala@linux.intel.com>
> >>>Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> >>>Cc: <stable@vger.kernel.org> # v4.9+
> >>>Signed-off-by: Imre Deak <imre.deak@intel.com>
> >>>---
> >>>  drivers/gpu/drm/i915/intel_dp.c     | 4 ++--
> >>>  drivers/gpu/drm/i915/intel_drv.h    | 2 ++
> >>>  drivers/gpu/drm/i915/intel_lspcon.c | 5 ++++-
> >>>  3 files changed, 8 insertions(+), 3 deletions(-)
> >>>
> >>>diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> >>>index e0f9b9e..a7785ce 100644
> >>>--- a/drivers/gpu/drm/i915/intel_dp.c
> >>>+++ b/drivers/gpu/drm/i915/intel_dp.c
> >>>@@ -4400,8 +4400,8 @@ static bool bxt_digital_port_connected(struct drm_i915_private *dev_priv,
> >>>   *
> >>>   * Return %true if @port is connected, %false otherwise.
> >>>   */
> >>>-static bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
> >>>-					 struct intel_digital_port *port)
> >>>+bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
> >>>+				  struct intel_digital_port *port)
> >>>  {
> >>>  	if (HAS_PCH_IBX(dev_priv))
> >>>  		return ibx_digital_port_connected(dev_priv, port);
> >>>diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> >>>index b71fece..b9cde11 100644
> >>>--- a/drivers/gpu/drm/i915/intel_drv.h
> >>>+++ b/drivers/gpu/drm/i915/intel_drv.h
> >>>@@ -1489,6 +1489,8 @@ bool __intel_dp_read_desc(struct intel_dp *intel_dp,
> >>>  bool intel_dp_read_desc(struct intel_dp *intel_dp);
> >>>  int intel_dp_link_required(int pixel_clock, int bpp);
> >>>  int intel_dp_max_data_rate(int max_link_clock, int max_lanes);
> >>>+bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
> >>>+				  struct intel_digital_port *port);
> >>>  /* intel_dp_aux_backlight.c */
> >>>  int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector);
> >>>diff --git a/drivers/gpu/drm/i915/intel_lspcon.c b/drivers/gpu/drm/i915/intel_lspcon.c
> >>>index f6d4e69..c300647 100644
> >>>--- a/drivers/gpu/drm/i915/intel_lspcon.c
> >>>+++ b/drivers/gpu/drm/i915/intel_lspcon.c
> >>>@@ -158,6 +158,8 @@ static bool lspcon_probe(struct intel_lspcon *lspcon)
> >>>  static void lspcon_resume_in_pcon_wa(struct intel_lspcon *lspcon)
> >>>  {
> >>>  	struct intel_dp *intel_dp = lspcon_to_intel_dp(lspcon);
> >>>+	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
> >>>+	struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
> >>>  	unsigned long start = jiffies;
> >>>  	if (!lspcon->desc_valid)
> >>>@@ -173,7 +175,8 @@ static void lspcon_resume_in_pcon_wa(struct intel_lspcon *lspcon)
> >>>  		if (!__intel_dp_read_desc(intel_dp, &desc))
> >>>  			return;
> >>>-		if (!memcmp(&intel_dp->desc, &desc, sizeof(desc))) {
> >>>+		if (intel_digital_port_connected(dev_priv, dig_port) &&
> >>when in PCON mode, live_status is always up for LSPCON port, so this check
> >>will be always true, isn't it ?
> >Not at least in case of the MegaChips LSPCON I've seen, there it takes a
> >while for HPD to get asserted. And while it's not asserted AUX
> >transactions will either:
> >- return garbage in case of native AUX transactions
> >- hang the chip/FW until next cold reboot in case of I2C-over-AUX
> >   transactions
> >- simply not get a reply if the chip/FW initialization has reached a
> >   certain phase
> >
> >Based on the DP specification the sink/branch device is not required to
> >respond in case the HPD is not asserted, so the 3rd scenario is
> >compliant, but the first two are not.
> >
> >In PCON mode after initialization and HPD getting asserted, HPD will
> >stay asserted except for the short pulses signaling an output
> >connect/disconnect.
> The reason might be, that LSPCON resumes in LS type2 adapter state, where
> the live_status behavior is normal
> and reflects the real HPD line, but the moment we move to PCON mode, HPD
> gets asserted low.

No, this chip/firmware resumes in PCON mode not in LS mode. Otherwise
native AUX transfers wouldn't return any reply (per LSPCON
specification) and HPD wouldn't get asserted on its own without a
display connected. Notice that we only check the LS/PCON state and
change it to PCON mode if necessary only after HPD gets asserted.

--Imre

> I know you would have tested this well, but I also want to test this code
> and logic first, before we go ahead with the patch.
> 
> Shashank
> >--Imre
> >
> >>- Shashank
> >>>+		    !memcmp(&intel_dp->desc, &desc, sizeof(desc))) {
> >>>  			DRM_DEBUG_KMS("LSPCON recovering in PCON mode after %u ms\n",
> >>>  				      jiffies_to_msecs(jiffies - start));
> >>>  			return;
> 

Re: [PATCH 2/4] drm/i915/lspcon: Fix resume time initialization due to unasserted HPD

[Sharma, Shashank]

Reviewed-by: Shashank Sharma

Regards
Shashank
On 1/29/2017 9:43 PM, Imre Deak wrote:
> On Sun, Jan 29, 2017 at 10:33:07AM +0530, Sharma, Shashank wrote:
>> Regards
>>
>> Shashank
>>
>>
>> On 1/28/2017 1:47 PM, Imre Deak wrote:
>>> On Sat, Jan 28, 2017 at 10:32:03AM +0530, Sharma, Shashank wrote:
>>>> Regards
>>>>
>>>> Shashank
>>>>
>>>>
>>>> On 1/27/2017 3:09 PM, Imre Deak wrote:
>>>>> During system resume time initialization the HPD level on LSPCON ports
>>>>> can stay low for an extended amount of time, leading to failed AUX
>>>>> transfers and LSPCON initialization. Fix this by waiting for HPD to get
>>>>> asserted.
>>>>>
>>>>> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99178
>>>>> Cc: Shashank Sharma <shashank.sharma@intel.com>
>>>>> Cc: Jani Nikula <jani.nikula@linux.intel.com>
>>>>> Cc: Ville Syrj�l� <ville.syrjala@linux.intel.com>
>>>>> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
>>>>> Cc: <stable@vger.kernel.org> # v4.9+
>>>>> Signed-off-by: Imre Deak <imre.deak@intel.com>
>>>>> ---
>>>>>   drivers/gpu/drm/i915/intel_dp.c     | 4 ++--
>>>>>   drivers/gpu/drm/i915/intel_drv.h    | 2 ++
>>>>>   drivers/gpu/drm/i915/intel_lspcon.c | 5 ++++-
>>>>>   3 files changed, 8 insertions(+), 3 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
>>>>> index e0f9b9e..a7785ce 100644
>>>>> --- a/drivers/gpu/drm/i915/intel_dp.c
>>>>> +++ b/drivers/gpu/drm/i915/intel_dp.c
>>>>> @@ -4400,8 +4400,8 @@ static bool bxt_digital_port_connected(struct drm_i915_private *dev_priv,
>>>>>    *
>>>>>    * Return %true if @port is connected, %false otherwise.
>>>>>    */
>>>>> -static bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
>>>>> -					 struct intel_digital_port *port)
>>>>> +bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
>>>>> +				  struct intel_digital_port *port)
>>>>>   {
>>>>>   	if (HAS_PCH_IBX(dev_priv))
>>>>>   		return ibx_digital_port_connected(dev_priv, port);
>>>>> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>>>>> index b71fece..b9cde11 100644
>>>>> --- a/drivers/gpu/drm/i915/intel_drv.h
>>>>> +++ b/drivers/gpu/drm/i915/intel_drv.h
>>>>> @@ -1489,6 +1489,8 @@ bool __intel_dp_read_desc(struct intel_dp *intel_dp,
>>>>>   bool intel_dp_read_desc(struct intel_dp *intel_dp);
>>>>>   int intel_dp_link_required(int pixel_clock, int bpp);
>>>>>   int intel_dp_max_data_rate(int max_link_clock, int max_lanes);
>>>>> +bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
>>>>> +				  struct intel_digital_port *port);
>>>>>   /* intel_dp_aux_backlight.c */
>>>>>   int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector);
>>>>> diff --git a/drivers/gpu/drm/i915/intel_lspcon.c b/drivers/gpu/drm/i915/intel_lspcon.c
>>>>> index f6d4e69..c300647 100644
>>>>> --- a/drivers/gpu/drm/i915/intel_lspcon.c
>>>>> +++ b/drivers/gpu/drm/i915/intel_lspcon.c
>>>>> @@ -158,6 +158,8 @@ static bool lspcon_probe(struct intel_lspcon *lspcon)
>>>>>   static void lspcon_resume_in_pcon_wa(struct intel_lspcon *lspcon)
>>>>>   {
>>>>>   	struct intel_dp *intel_dp = lspcon_to_intel_dp(lspcon);
>>>>> +	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
>>>>> +	struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
>>>>>   	unsigned long start = jiffies;
>>>>>   	if (!lspcon->desc_valid)
>>>>> @@ -173,7 +175,8 @@ static void lspcon_resume_in_pcon_wa(struct intel_lspcon *lspcon)
>>>>>   		if (!__intel_dp_read_desc(intel_dp, &desc))
>>>>>   			return;
>>>>> -		if (!memcmp(&intel_dp->desc, &desc, sizeof(desc))) {
>>>>> +		if (intel_digital_port_connected(dev_priv, dig_port) &&
>>>> when in PCON mode, live_status is always up for LSPCON port, so this check
>>>> will be always true, isn't it ?
>>> Not at least in case of the MegaChips LSPCON I've seen, there it takes a
>>> while for HPD to get asserted. And while it's not asserted AUX
>>> transactions will either:
>>> - return garbage in case of native AUX transactions
>>> - hang the chip/FW until next cold reboot in case of I2C-over-AUX
>>>    transactions
>>> - simply not get a reply if the chip/FW initialization has reached a
>>>    certain phase
>>>
>>> Based on the DP specification the sink/branch device is not required to
>>> respond in case the HPD is not asserted, so the 3rd scenario is
>>> compliant, but the first two are not.
>>>
>>> In PCON mode after initialization and HPD getting asserted, HPD will
>>> stay asserted except for the short pulses signaling an output
>>> connect/disconnect.
>> The reason might be, that LSPCON resumes in LS type2 adapter state, where
>> the live_status behavior is normal
>> and reflects the real HPD line, but the moment we move to PCON mode, HPD
>> gets asserted low.
> No, this chip/firmware resumes in PCON mode not in LS mode. Otherwise
> native AUX transfers wouldn't return any reply (per LSPCON
> specification) and HPD wouldn't get asserted on its own without a
> display connected. Notice that we only check the LS/PCON state and
> change it to PCON mode if necessary only after HPD gets asserted.
>
> --Imre
>
>> I know you would have tested this well, but I also want to test this code
>> and logic first, before we go ahead with the patch.
>>
>> Shashank
>>> --Imre
>>>
>>>> - Shashank
>>>>> +		    !memcmp(&intel_dp->desc, &desc, sizeof(desc))) {
>>>>>   			DRM_DEBUG_KMS("LSPCON recovering in PCON mode after %u ms\n",
>>>>>   				      jiffies_to_msecs(jiffies - start));
>>>>>   			return;