[PATCH v6 1/3] intel_acpi: Rename drm_dev local variable to dev

[PATCH v6 1/3] intel_acpi: Rename drm_dev local variable to dev

[Rajat Jain]

Change the struct drm_device * local variable from drm_dev to dev
per the feedback received here:
https://lkml.org/lkml/2020/1/24/1143

Signed-off-by: Rajat Jain <rajatja@google.com>
---
v6: Initial patch (v6 to match other patches in the set) 

 drivers/gpu/drm/i915/display/intel_acpi.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_acpi.c b/drivers/gpu/drm/i915/display/intel_acpi.c
index e21fb14d5e07b..3e6831cca4ac1 100644
--- a/drivers/gpu/drm/i915/display/intel_acpi.c
+++ b/drivers/gpu/drm/i915/display/intel_acpi.c
@@ -224,13 +224,13 @@ static u32 acpi_display_type(struct intel_connector *connector)
 
 void intel_acpi_device_id_update(struct drm_i915_private *dev_priv)
 {
-	struct drm_device *drm_dev = &dev_priv->drm;
+	struct drm_device *dev = &dev_priv->drm;
 	struct intel_connector *connector;
 	struct drm_connector_list_iter conn_iter;
 	u8 display_index[16] = {};
 
 	/* Populate the ACPI IDs for all connectors for a given drm_device */
-	drm_connector_list_iter_begin(drm_dev, &conn_iter);
+	drm_connector_list_iter_begin(dev, &conn_iter);
 	for_each_intel_connector_iter(connector, &conn_iter) {
 		u32 device_id, type;
 
-- 
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[PATCH v6 2/3] drm/i915: Lookup and attach ACPI device node for connectors

[Rajat Jain]

Lookup and attach ACPI nodes for intel connectors. The lookup is done
in compliance with ACPI Spec 6.3
https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf
(Ref: Pages 1119 - 1123).

This can be useful for any connector specific platform properties. (This
will be used for privacy screen in next patch).

Signed-off-by: Rajat Jain <rajatja@google.com>
---
v6: Addressed minor comments from Jani at
    https://lkml.org/lkml/2020/1/24/1143
     - local variable renamed.
     - used drm_dbg_kms()
     - used acpi_device_handle()
     - Used opaque type acpi_handle instead of void*
v5: same as v4
v4: Same as v3
v3: fold the code into existing acpi_device_id_update() function
v2: formed by splitting the original patch into ACPI lookup, and privacy
    screen property. Also move it into i915 now that I found existing code
    in i915 that can be re-used.

 drivers/gpu/drm/i915/display/intel_acpi.c     | 24 +++++++++++++++++++
 .../drm/i915/display/intel_display_types.h    |  5 ++++
 drivers/gpu/drm/i915/display/intel_dp.c       |  3 +++
 3 files changed, 32 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_acpi.c b/drivers/gpu/drm/i915/display/intel_acpi.c
index 3e6831cca4ac1..870c1ad98df92 100644
--- a/drivers/gpu/drm/i915/display/intel_acpi.c
+++ b/drivers/gpu/drm/i915/display/intel_acpi.c
@@ -222,11 +222,22 @@ static u32 acpi_display_type(struct intel_connector *connector)
 	return display_type;
 }
 
+/*
+ * Ref: ACPI Spec 6.3
+ * https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf
+ * Pages 1119 - 1123 describe, what I believe, a standard way of
+ * identifying / addressing "display panels" in the ACPI. It provides
+ * a way for the ACPI to define devices for the display panels attached
+ * to the system. It thus provides a way for the BIOS to export any panel
+ * specific properties to the system via ACPI (like device trees).
+ */
 void intel_acpi_device_id_update(struct drm_i915_private *dev_priv)
 {
 	struct drm_device *dev = &dev_priv->drm;
 	struct intel_connector *connector;
 	struct drm_connector_list_iter conn_iter;
+	struct acpi_device *conn_dev;
+	u64 conn_addr;
 	u8 display_index[16] = {};
 
 	/* Populate the ACPI IDs for all connectors for a given drm_device */
@@ -242,6 +253,19 @@ void intel_acpi_device_id_update(struct drm_i915_private *dev_priv)
 		device_id |= display_index[type]++ << ACPI_DISPLAY_INDEX_SHIFT;
 
 		connector->acpi_device_id = device_id;
+
+		/* Build the _ADR to look for */
+		conn_addr = device_id | ACPI_DEVICE_ID_SCHEME |
+				ACPI_BIOS_CAN_DETECT;
+
+		drm_dbg_kms(dev, "Checking connector ACPI node at _ADR=%llX\n",
+			    conn_addr);
+
+		/* Look up the connector device, under the PCI device */
+		conn_dev = acpi_find_child_device(
+					ACPI_COMPANION(&dev->pdev->dev),
+					conn_addr, false);
+		connector->acpi_handle = acpi_device_handle(conn_dev);
 	}
 	drm_connector_list_iter_end(&conn_iter);
 }
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index 5e00e611f077f..d70612cc1ba2a 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -411,9 +411,14 @@ struct intel_connector {
 	 */
 	struct intel_encoder *encoder;
 
+#ifdef CONFIG_ACPI
 	/* ACPI device id for ACPI and driver cooperation */
 	u32 acpi_device_id;
 
+	/* ACPI handle corresponding to this connector display, if found */
+	acpi_handle acpi_handle;
+#endif
+
 	/* Reads out the current hw, returning true if the connector is enabled
 	 * and active (i.e. dpms ON state). */
 	bool (*get_hw_state)(struct intel_connector *);
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 0a417cd2af2bc..171821113d362 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -44,6 +44,7 @@
 #include "i915_debugfs.h"
 #include "i915_drv.h"
 #include "i915_trace.h"
+#include "intel_acpi.h"
 #include "intel_atomic.h"
 #include "intel_audio.h"
 #include "intel_connector.h"
@@ -6868,6 +6869,8 @@ intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connect
 
 		connector->state->scaling_mode = DRM_MODE_SCALE_ASPECT;
 
+		/* Lookup the ACPI node corresponding to the connector */
+		intel_acpi_device_id_update(dev_priv);
 	}
 }
 
-- 
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[PATCH v6 3/3] drm/i915: Add support for integrated privacy screens

[Rajat Jain]

Certain laptops now come with panels that have integrated privacy
screens on them. This patch adds support for such panels by adding
a privacy-screen property to the intel_connector for the panel, that
the userspace can then use to control and check the status.

Identifying the presence of privacy screen, and controlling it, is done
via ACPI _DSM methods.

Currently, this is done only for the Intel display ports. But in future,
this can be done for any other ports if the hardware becomes available
(e.g. external monitors supporting integrated privacy screens?).

Signed-off-by: Rajat Jain <rajatja@google.com>
---
v6: Always initialize prop in intel_attach_privacy_screen_property()
v5: fix a cosmetic checkpatch warning
v4: Fix a typo in intel_privacy_screen.h
v3: * Change license to GPL-2.0 OR MIT
    * Move privacy screen enum from UAPI to intel_display_types.h
    * Rename parameter name and some other minor changes.
v2: Formed by splitting the original patch into multiple patches.
    - All code has been moved into i915 now.
    - Privacy screen is a i915 property
    - Have a local state variable to store the prvacy screen. Don't read
      it from hardware.

 drivers/gpu/drm/i915/Makefile                 |  3 +-
 drivers/gpu/drm/i915/display/intel_atomic.c   | 13 +++-
 .../gpu/drm/i915/display/intel_connector.c    | 35 +++++++++
 .../gpu/drm/i915/display/intel_connector.h    |  1 +
 .../drm/i915/display/intel_display_types.h    | 18 +++++
 drivers/gpu/drm/i915/display/intel_dp.c       |  6 ++
 .../drm/i915/display/intel_privacy_screen.c   | 72 +++++++++++++++++++
 .../drm/i915/display/intel_privacy_screen.h   | 27 +++++++
 8 files changed, 171 insertions(+), 4 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/display/intel_privacy_screen.c
 create mode 100644 drivers/gpu/drm/i915/display/intel_privacy_screen.h

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 991a8c537d123..825951b4cd006 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -208,7 +208,8 @@ i915-y += \
 	display/intel_vga.o
 i915-$(CONFIG_ACPI) += \
 	display/intel_acpi.o \
-	display/intel_opregion.o
+	display/intel_opregion.o \
+	display/intel_privacy_screen.o
 i915-$(CONFIG_DRM_FBDEV_EMULATION) += \
 	display/intel_fbdev.o
 
diff --git a/drivers/gpu/drm/i915/display/intel_atomic.c b/drivers/gpu/drm/i915/display/intel_atomic.c
index d043057d2fa03..4ed537c877777 100644
--- a/drivers/gpu/drm/i915/display/intel_atomic.c
+++ b/drivers/gpu/drm/i915/display/intel_atomic.c
@@ -40,6 +40,7 @@
 #include "intel_global_state.h"
 #include "intel_hdcp.h"
 #include "intel_psr.h"
+#include "intel_privacy_screen.h"
 #include "intel_sprite.h"
 
 /**
@@ -60,11 +61,14 @@ int intel_digital_connector_atomic_get_property(struct drm_connector *connector,
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	struct intel_digital_connector_state *intel_conn_state =
 		to_intel_digital_connector_state(state);
+	struct intel_connector *intel_connector = to_intel_connector(connector);
 
 	if (property == dev_priv->force_audio_property)
 		*val = intel_conn_state->force_audio;
 	else if (property == dev_priv->broadcast_rgb_property)
 		*val = intel_conn_state->broadcast_rgb;
+	else if (property == intel_connector->privacy_screen_property)
+		*val = intel_conn_state->privacy_screen_status;
 	else {
 		drm_dbg_atomic(&dev_priv->drm,
 			       "Unknown property [PROP:%d:%s]\n",
@@ -93,15 +97,18 @@ int intel_digital_connector_atomic_set_property(struct drm_connector *connector,
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	struct intel_digital_connector_state *intel_conn_state =
 		to_intel_digital_connector_state(state);
+	struct intel_connector *intel_connector = to_intel_connector(connector);
 
 	if (property == dev_priv->force_audio_property) {
 		intel_conn_state->force_audio = val;
 		return 0;
-	}
-
-	if (property == dev_priv->broadcast_rgb_property) {
+	} else if (property == dev_priv->broadcast_rgb_property) {
 		intel_conn_state->broadcast_rgb = val;
 		return 0;
+	} else if (property == intel_connector->privacy_screen_property) {
+		intel_privacy_screen_set_val(intel_connector, val);
+		intel_conn_state->privacy_screen_status = val;
+		return 0;
 	}
 
 	drm_dbg_atomic(&dev_priv->drm, "Unknown property [PROP:%d:%s]\n",
diff --git a/drivers/gpu/drm/i915/display/intel_connector.c b/drivers/gpu/drm/i915/display/intel_connector.c
index 903e49659f561..55f80219cb269 100644
--- a/drivers/gpu/drm/i915/display/intel_connector.c
+++ b/drivers/gpu/drm/i915/display/intel_connector.c
@@ -297,3 +297,38 @@ intel_attach_colorspace_property(struct drm_connector *connector)
 	drm_object_attach_property(&connector->base,
 				   connector->colorspace_property, 0);
 }
+
+static const struct drm_prop_enum_list privacy_screen_enum[] = {
+	{ PRIVACY_SCREEN_DISABLED, "Disabled" },
+	{ PRIVACY_SCREEN_ENABLED, "Enabled" },
+};
+
+/**
+ * intel_attach_privacy_screen_property -
+ *     create and attach the connecter's privacy-screen property. *
+ * @connector: connector for which to init the privacy-screen property
+ *
+ * This function creates and attaches the "privacy-screen" property to the
+ * connector. Initial state of privacy-screen is set to disabled.
+ */
+void
+intel_attach_privacy_screen_property(struct drm_connector *connector)
+{
+	struct intel_connector *intel_connector = to_intel_connector(connector);
+	struct drm_property *prop = intel_connector->privacy_screen_property;
+
+	if (!prop) {
+		prop = drm_property_create_enum(connector->dev,
+						DRM_MODE_PROP_ENUM,
+						"privacy-screen",
+						privacy_screen_enum,
+					    ARRAY_SIZE(privacy_screen_enum));
+		if (!prop)
+			return;
+
+		intel_connector->privacy_screen_property = prop;
+	}
+
+	drm_object_attach_property(&connector->base, prop,
+				   PRIVACY_SCREEN_DISABLED);
+}
diff --git a/drivers/gpu/drm/i915/display/intel_connector.h b/drivers/gpu/drm/i915/display/intel_connector.h
index 93a7375c8196d..61005f37a3385 100644
--- a/drivers/gpu/drm/i915/display/intel_connector.h
+++ b/drivers/gpu/drm/i915/display/intel_connector.h
@@ -31,5 +31,6 @@ void intel_attach_force_audio_property(struct drm_connector *connector);
 void intel_attach_broadcast_rgb_property(struct drm_connector *connector);
 void intel_attach_aspect_ratio_property(struct drm_connector *connector);
 void intel_attach_colorspace_property(struct drm_connector *connector);
+void intel_attach_privacy_screen_property(struct drm_connector *connector);
 
 #endif /* __INTEL_CONNECTOR_H__ */
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index d70612cc1ba2a..de20effb3e073 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -442,6 +442,23 @@ struct intel_connector {
 	struct work_struct modeset_retry_work;
 
 	struct intel_hdcp hdcp;
+
+	/* Optional "privacy-screen" property for the connector panel */
+	struct drm_property *privacy_screen_property;
+};
+
+/**
+ * enum intel_privacy_screen_status - privacy_screen status
+ *
+ * This enum is used to track and control the state of the integrated privacy
+ * screen present on some display panels, via the "privacy-screen" property.
+ *
+ * @PRIVACY_SCREEN_DISABLED: The privacy-screen on the panel is disabled
+ * @PRIVACY_SCREEN_ENABLED:  The privacy-screen on the panel is enabled
+ **/
+enum intel_privacy_screen_status {
+	PRIVACY_SCREEN_DISABLED = 0,
+	PRIVACY_SCREEN_ENABLED = 1,
 };
 
 struct intel_digital_connector_state {
@@ -449,6 +466,7 @@ struct intel_digital_connector_state {
 
 	enum hdmi_force_audio force_audio;
 	int broadcast_rgb;
+	enum intel_privacy_screen_status privacy_screen_status;
 };
 
 #define to_intel_digital_connector_state(x) container_of(x, struct intel_digital_connector_state, base)
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 171821113d362..ff76c799364d0 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -62,6 +62,7 @@
 #include "intel_lspcon.h"
 #include "intel_lvds.h"
 #include "intel_panel.h"
+#include "intel_privacy_screen.h"
 #include "intel_psr.h"
 #include "intel_sideband.h"
 #include "intel_tc.h"
@@ -6841,6 +6842,7 @@ intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connect
 {
 	struct drm_i915_private *dev_priv = to_i915(connector->dev);
 	enum port port = dp_to_dig_port(intel_dp)->base.port;
+	struct intel_connector *intel_connector = to_intel_connector(connector);
 
 	if (!IS_G4X(dev_priv) && port != PORT_A)
 		intel_attach_force_audio_property(connector);
@@ -6871,6 +6873,10 @@ intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connect
 
 		/* Lookup the ACPI node corresponding to the connector */
 		intel_acpi_device_id_update(dev_priv);
+
+		/* Check for integrated Privacy screen support */
+		if (intel_privacy_screen_present(intel_connector))
+			intel_attach_privacy_screen_property(connector);
 	}
 }
 
diff --git a/drivers/gpu/drm/i915/display/intel_privacy_screen.c b/drivers/gpu/drm/i915/display/intel_privacy_screen.c
new file mode 100644
index 0000000000000..c8a5b64f94fb7
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_privacy_screen.c
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+/*
+ * Intel ACPI privacy screen code
+ *
+ * Copyright © 2019 Google Inc.
+ */
+
+#include <linux/acpi.h>
+
+#include "intel_privacy_screen.h"
+
+#define CONNECTOR_DSM_REVID 1
+
+#define CONNECTOR_DSM_FN_PRIVACY_ENABLE		2
+#define CONNECTOR_DSM_FN_PRIVACY_DISABLE		3
+
+static const guid_t drm_conn_dsm_guid =
+	GUID_INIT(0xC7033113, 0x8720, 0x4CEB,
+		  0x90, 0x90, 0x9D, 0x52, 0xB3, 0xE5, 0x2D, 0x73);
+
+/* Makes _DSM call to set privacy screen status */
+static void acpi_privacy_screen_call_dsm(acpi_handle conn_handle, u64 func)
+{
+	union acpi_object *obj;
+
+	obj = acpi_evaluate_dsm(conn_handle, &drm_conn_dsm_guid,
+				CONNECTOR_DSM_REVID, func, NULL);
+	if (!obj) {
+		DRM_DEBUG_DRIVER("failed to evaluate _DSM for fn %llx\n", func);
+		return;
+	}
+
+	ACPI_FREE(obj);
+}
+
+void intel_privacy_screen_set_val(struct intel_connector *connector,
+				  enum intel_privacy_screen_status val)
+{
+	acpi_handle acpi_handle = connector->acpi_handle;
+
+	if (!acpi_handle)
+		return;
+
+	if (val == PRIVACY_SCREEN_DISABLED)
+		acpi_privacy_screen_call_dsm(acpi_handle,
+					     CONNECTOR_DSM_FN_PRIVACY_DISABLE);
+	else if (val == PRIVACY_SCREEN_ENABLED)
+		acpi_privacy_screen_call_dsm(acpi_handle,
+					     CONNECTOR_DSM_FN_PRIVACY_ENABLE);
+	else
+		DRM_WARN("%s: Cannot set privacy screen to invalid val %u\n",
+			 dev_name(connector->base.dev->dev), val);
+}
+
+bool intel_privacy_screen_present(struct intel_connector *connector)
+{
+	acpi_handle handle = connector->acpi_handle;
+
+	if (!handle)
+		return false;
+
+	if (!acpi_check_dsm(handle, &drm_conn_dsm_guid,
+			    CONNECTOR_DSM_REVID,
+			    1 << CONNECTOR_DSM_FN_PRIVACY_ENABLE |
+			    1 << CONNECTOR_DSM_FN_PRIVACY_DISABLE)) {
+		DRM_WARN("%s: Odd, connector ACPI node but no privacy scrn?\n",
+			 dev_name(connector->base.dev->dev));
+		return false;
+	}
+	DRM_DEV_INFO(connector->base.dev->dev, "supports privacy screen\n");
+	return true;
+}
diff --git a/drivers/gpu/drm/i915/display/intel_privacy_screen.h b/drivers/gpu/drm/i915/display/intel_privacy_screen.h
new file mode 100644
index 0000000000000..74013a7885c70
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_privacy_screen.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 OR MIT */
+/*
+ * Copyright © 2019 Google Inc.
+ */
+
+#ifndef __DRM_PRIVACY_SCREEN_H__
+#define __DRM_PRIVACY_SCREEN_H__
+
+#include "intel_display_types.h"
+
+#ifdef CONFIG_ACPI
+bool intel_privacy_screen_present(struct intel_connector *connector);
+void intel_privacy_screen_set_val(struct intel_connector *connector,
+				  enum intel_privacy_screen_status val);
+#else
+static bool intel_privacy_screen_present(struct intel_connector *connector)
+{
+	return false;
+}
+
+static void
+intel_privacy_screen_set_val(struct intel_connector *connector,
+			     enum intel_privacy_screen_status val)
+{ }
+#endif /* CONFIG_ACPI */
+
+#endif /* __DRM_PRIVACY_SCREEN_H__ */
-- 
2.25.0.265.gbab2e86ba0-goog

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Re: [PATCH v6 1/3] intel_acpi: Rename drm_dev local variable to dev

[Jani Nikula]

On Wed, 04 Mar 2020, Rajat Jain <rajatja@google.com> wrote:
> Change the struct drm_device * local variable from drm_dev to dev
> per the feedback received here:
> https://lkml.org/lkml/2020/1/24/1143
>
> Signed-off-by: Rajat Jain <rajatja@google.com>

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

> ---
> v6: Initial patch (v6 to match other patches in the set) 
>
>  drivers/gpu/drm/i915/display/intel_acpi.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_acpi.c b/drivers/gpu/drm/i915/display/intel_acpi.c
> index e21fb14d5e07b..3e6831cca4ac1 100644
> --- a/drivers/gpu/drm/i915/display/intel_acpi.c
> +++ b/drivers/gpu/drm/i915/display/intel_acpi.c
> @@ -224,13 +224,13 @@ static u32 acpi_display_type(struct intel_connector *connector)
>  
>  void intel_acpi_device_id_update(struct drm_i915_private *dev_priv)
>  {
> -	struct drm_device *drm_dev = &dev_priv->drm;
> +	struct drm_device *dev = &dev_priv->drm;
>  	struct intel_connector *connector;
>  	struct drm_connector_list_iter conn_iter;
>  	u8 display_index[16] = {};
>  
>  	/* Populate the ACPI IDs for all connectors for a given drm_device */
> -	drm_connector_list_iter_begin(drm_dev, &conn_iter);
> +	drm_connector_list_iter_begin(dev, &conn_iter);
>  	for_each_intel_connector_iter(connector, &conn_iter) {
>  		u32 device_id, type;

-- 
Jani Nikula, Intel Open Source Graphics Center
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Re: [PATCH v6 2/3] drm/i915: Lookup and attach ACPI device node for connectors

[Jani Nikula]

On Wed, 04 Mar 2020, Rajat Jain <rajatja@google.com> wrote:
> Lookup and attach ACPI nodes for intel connectors. The lookup is done
> in compliance with ACPI Spec 6.3
> https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf
> (Ref: Pages 1119 - 1123).
>
> This can be useful for any connector specific platform properties. (This
> will be used for privacy screen in next patch).
>
> Signed-off-by: Rajat Jain <rajatja@google.com>
> ---
> v6: Addressed minor comments from Jani at
>     https://lkml.org/lkml/2020/1/24/1143
>      - local variable renamed.
>      - used drm_dbg_kms()
>      - used acpi_device_handle()
>      - Used opaque type acpi_handle instead of void*
> v5: same as v4
> v4: Same as v3
> v3: fold the code into existing acpi_device_id_update() function
> v2: formed by splitting the original patch into ACPI lookup, and privacy
>     screen property. Also move it into i915 now that I found existing code
>     in i915 that can be re-used.
>
>  drivers/gpu/drm/i915/display/intel_acpi.c     | 24 +++++++++++++++++++
>  .../drm/i915/display/intel_display_types.h    |  5 ++++
>  drivers/gpu/drm/i915/display/intel_dp.c       |  3 +++
>  3 files changed, 32 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_acpi.c b/drivers/gpu/drm/i915/display/intel_acpi.c
> index 3e6831cca4ac1..870c1ad98df92 100644
> --- a/drivers/gpu/drm/i915/display/intel_acpi.c
> +++ b/drivers/gpu/drm/i915/display/intel_acpi.c
> @@ -222,11 +222,22 @@ static u32 acpi_display_type(struct intel_connector *connector)
>  	return display_type;
>  }
>  
> +/*
> + * Ref: ACPI Spec 6.3
> + * https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf
> + * Pages 1119 - 1123 describe, what I believe, a standard way of
> + * identifying / addressing "display panels" in the ACPI. It provides
> + * a way for the ACPI to define devices for the display panels attached
> + * to the system. It thus provides a way for the BIOS to export any panel
> + * specific properties to the system via ACPI (like device trees).
> + */
>  void intel_acpi_device_id_update(struct drm_i915_private *dev_priv)
>  {
>  	struct drm_device *dev = &dev_priv->drm;
>  	struct intel_connector *connector;
>  	struct drm_connector_list_iter conn_iter;
> +	struct acpi_device *conn_dev;
> +	u64 conn_addr;
>  	u8 display_index[16] = {};
>  
>  	/* Populate the ACPI IDs for all connectors for a given drm_device */
> @@ -242,6 +253,19 @@ void intel_acpi_device_id_update(struct drm_i915_private *dev_priv)
>  		device_id |= display_index[type]++ << ACPI_DISPLAY_INDEX_SHIFT;
>  
>  		connector->acpi_device_id = device_id;
> +
> +		/* Build the _ADR to look for */
> +		conn_addr = device_id | ACPI_DEVICE_ID_SCHEME |
> +				ACPI_BIOS_CAN_DETECT;
> +
> +		drm_dbg_kms(dev, "Checking connector ACPI node at _ADR=%llX\n",
> +			    conn_addr);
> +
> +		/* Look up the connector device, under the PCI device */
> +		conn_dev = acpi_find_child_device(
> +					ACPI_COMPANION(&dev->pdev->dev),
> +					conn_addr, false);
> +		connector->acpi_handle = acpi_device_handle(conn_dev);
>  	}
>  	drm_connector_list_iter_end(&conn_iter);
>  }
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 5e00e611f077f..d70612cc1ba2a 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -411,9 +411,14 @@ struct intel_connector {
>  	 */
>  	struct intel_encoder *encoder;
>  
> +#ifdef CONFIG_ACPI
>  	/* ACPI device id for ACPI and driver cooperation */
>  	u32 acpi_device_id;
>  
> +	/* ACPI handle corresponding to this connector display, if found */
> +	acpi_handle acpi_handle;
> +#endif
> +
>  	/* Reads out the current hw, returning true if the connector is enabled
>  	 * and active (i.e. dpms ON state). */
>  	bool (*get_hw_state)(struct intel_connector *);
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 0a417cd2af2bc..171821113d362 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -44,6 +44,7 @@
>  #include "i915_debugfs.h"
>  #include "i915_drv.h"
>  #include "i915_trace.h"
> +#include "intel_acpi.h"
>  #include "intel_atomic.h"
>  #include "intel_audio.h"
>  #include "intel_connector.h"
> @@ -6868,6 +6869,8 @@ intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connect
>  
>  		connector->state->scaling_mode = DRM_MODE_SCALE_ASPECT;
>  
> +		/* Lookup the ACPI node corresponding to the connector */
> +		intel_acpi_device_id_update(dev_priv);

I find this part problematic.

Normally, we call the function at probe via i915_driver_register() ->
intel_opregion_register() -> intel_opregion_resume() ->
intel_didl_outputs() -> intel_acpi_device_id_update(). It gets called
*once* at probe, after we have all the outputs (and thus connectors)
figured out.

This in turn calls it for every DP connector, before we even have all
connectors registered. But it also re-iterates the previously handled
connectors again and again.

The problem, of course, is that you'll need connector->acpi_handle to
figure out whether the feature is present and whether the property is
needed. Figuring out acpi_handle also requires
connector->acpi_device_id.

It's a bit of a catch-22.

I think the options are:

1) See if we can postpone creating and attaching properties to connector
->late_register hook. (I didn't have the time to look into it yet, at
all.)

2) Provide a way to populate connector->acpi_device_id and
connector->acpi_handle on a per-connector basis. At least the device id
remains constant for the lifetime of the drm_device (why do we keep
updating it at every resume?!) but can we be sure ->acpi_handle does
too? (I don't really know my way around ACPI.)

BR,
Jani.


>  	}
>  }

-- 
Jani Nikula, Intel Open Source Graphics Center
_______________________________________________
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Re: [PATCH v6 3/3] drm/i915: Add support for integrated privacy screens

[Jani Nikula]

On Wed, 04 Mar 2020, Rajat Jain <rajatja@google.com> wrote:
> Certain laptops now come with panels that have integrated privacy
> screens on them. This patch adds support for such panels by adding
> a privacy-screen property to the intel_connector for the panel, that
> the userspace can then use to control and check the status.
>
> Identifying the presence of privacy screen, and controlling it, is done
> via ACPI _DSM methods.
>
> Currently, this is done only for the Intel display ports. But in future,
> this can be done for any other ports if the hardware becomes available
> (e.g. external monitors supporting integrated privacy screens?).

I think you should add the property at the drm core level in
drm_connector.c, not in i915, to ensure we have the same property across
drivers. Even if, for now, you leave the acpi implementation part in
i915.

More comments inline.

>
> Signed-off-by: Rajat Jain <rajatja@google.com>
> ---
> v6: Always initialize prop in intel_attach_privacy_screen_property()
> v5: fix a cosmetic checkpatch warning
> v4: Fix a typo in intel_privacy_screen.h
> v3: * Change license to GPL-2.0 OR MIT
>     * Move privacy screen enum from UAPI to intel_display_types.h
>     * Rename parameter name and some other minor changes.
> v2: Formed by splitting the original patch into multiple patches.
>     - All code has been moved into i915 now.
>     - Privacy screen is a i915 property
>     - Have a local state variable to store the prvacy screen. Don't read
>       it from hardware.
>
>  drivers/gpu/drm/i915/Makefile                 |  3 +-
>  drivers/gpu/drm/i915/display/intel_atomic.c   | 13 +++-
>  .../gpu/drm/i915/display/intel_connector.c    | 35 +++++++++
>  .../gpu/drm/i915/display/intel_connector.h    |  1 +
>  .../drm/i915/display/intel_display_types.h    | 18 +++++
>  drivers/gpu/drm/i915/display/intel_dp.c       |  6 ++
>  .../drm/i915/display/intel_privacy_screen.c   | 72 +++++++++++++++++++
>  .../drm/i915/display/intel_privacy_screen.h   | 27 +++++++
>  8 files changed, 171 insertions(+), 4 deletions(-)
>  create mode 100644 drivers/gpu/drm/i915/display/intel_privacy_screen.c
>  create mode 100644 drivers/gpu/drm/i915/display/intel_privacy_screen.h
>
> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> index 991a8c537d123..825951b4cd006 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -208,7 +208,8 @@ i915-y += \
>  	display/intel_vga.o
>  i915-$(CONFIG_ACPI) += \
>  	display/intel_acpi.o \
> -	display/intel_opregion.o
> +	display/intel_opregion.o \
> +	display/intel_privacy_screen.o
>  i915-$(CONFIG_DRM_FBDEV_EMULATION) += \
>  	display/intel_fbdev.o
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_atomic.c b/drivers/gpu/drm/i915/display/intel_atomic.c
> index d043057d2fa03..4ed537c877777 100644
> --- a/drivers/gpu/drm/i915/display/intel_atomic.c
> +++ b/drivers/gpu/drm/i915/display/intel_atomic.c
> @@ -40,6 +40,7 @@
>  #include "intel_global_state.h"
>  #include "intel_hdcp.h"
>  #include "intel_psr.h"
> +#include "intel_privacy_screen.h"
>  #include "intel_sprite.h"
>  
>  /**
> @@ -60,11 +61,14 @@ int intel_digital_connector_atomic_get_property(struct drm_connector *connector,
>  	struct drm_i915_private *dev_priv = to_i915(dev);
>  	struct intel_digital_connector_state *intel_conn_state =
>  		to_intel_digital_connector_state(state);
> +	struct intel_connector *intel_connector = to_intel_connector(connector);
>  
>  	if (property == dev_priv->force_audio_property)
>  		*val = intel_conn_state->force_audio;
>  	else if (property == dev_priv->broadcast_rgb_property)
>  		*val = intel_conn_state->broadcast_rgb;
> +	else if (property == intel_connector->privacy_screen_property)
> +		*val = intel_conn_state->privacy_screen_status;
>  	else {
>  		drm_dbg_atomic(&dev_priv->drm,
>  			       "Unknown property [PROP:%d:%s]\n",
> @@ -93,15 +97,18 @@ int intel_digital_connector_atomic_set_property(struct drm_connector *connector,
>  	struct drm_i915_private *dev_priv = to_i915(dev);
>  	struct intel_digital_connector_state *intel_conn_state =
>  		to_intel_digital_connector_state(state);
> +	struct intel_connector *intel_connector = to_intel_connector(connector);
>  
>  	if (property == dev_priv->force_audio_property) {
>  		intel_conn_state->force_audio = val;
>  		return 0;
> -	}
> -
> -	if (property == dev_priv->broadcast_rgb_property) {
> +	} else if (property == dev_priv->broadcast_rgb_property) {
>  		intel_conn_state->broadcast_rgb = val;
>  		return 0;
> +	} else if (property == intel_connector->privacy_screen_property) {
> +		intel_privacy_screen_set_val(intel_connector, val);

I think this part should only change the connector state. The driver
would then do the magic at commit stage according to the property value.

> +		intel_conn_state->privacy_screen_status = val;
> +		return 0;
>  	}
>  
>  	drm_dbg_atomic(&dev_priv->drm, "Unknown property [PROP:%d:%s]\n",
> diff --git a/drivers/gpu/drm/i915/display/intel_connector.c b/drivers/gpu/drm/i915/display/intel_connector.c
> index 903e49659f561..55f80219cb269 100644
> --- a/drivers/gpu/drm/i915/display/intel_connector.c
> +++ b/drivers/gpu/drm/i915/display/intel_connector.c
> @@ -297,3 +297,38 @@ intel_attach_colorspace_property(struct drm_connector *connector)
>  	drm_object_attach_property(&connector->base,
>  				   connector->colorspace_property, 0);
>  }
> +
> +static const struct drm_prop_enum_list privacy_screen_enum[] = {
> +	{ PRIVACY_SCREEN_DISABLED, "Disabled" },
> +	{ PRIVACY_SCREEN_ENABLED, "Enabled" },
> +};
> +
> +/**
> + * intel_attach_privacy_screen_property -
> + *     create and attach the connecter's privacy-screen property. *
> + * @connector: connector for which to init the privacy-screen property
> + *
> + * This function creates and attaches the "privacy-screen" property to the
> + * connector. Initial state of privacy-screen is set to disabled.
> + */
> +void
> +intel_attach_privacy_screen_property(struct drm_connector *connector)
> +{
> +	struct intel_connector *intel_connector = to_intel_connector(connector);
> +	struct drm_property *prop = intel_connector->privacy_screen_property;
> +
> +	if (!prop) {
> +		prop = drm_property_create_enum(connector->dev,
> +						DRM_MODE_PROP_ENUM,
> +						"privacy-screen",
> +						privacy_screen_enum,
> +					    ARRAY_SIZE(privacy_screen_enum));
> +		if (!prop)
> +			return;
> +
> +		intel_connector->privacy_screen_property = prop;
> +	}
> +
> +	drm_object_attach_property(&connector->base, prop,
> +				   PRIVACY_SCREEN_DISABLED);
> +}

This looks about right, except IMO should be part of drm_connector and
moved to drm_connector.c.

> diff --git a/drivers/gpu/drm/i915/display/intel_connector.h b/drivers/gpu/drm/i915/display/intel_connector.h
> index 93a7375c8196d..61005f37a3385 100644
> --- a/drivers/gpu/drm/i915/display/intel_connector.h
> +++ b/drivers/gpu/drm/i915/display/intel_connector.h
> @@ -31,5 +31,6 @@ void intel_attach_force_audio_property(struct drm_connector *connector);
>  void intel_attach_broadcast_rgb_property(struct drm_connector *connector);
>  void intel_attach_aspect_ratio_property(struct drm_connector *connector);
>  void intel_attach_colorspace_property(struct drm_connector *connector);
> +void intel_attach_privacy_screen_property(struct drm_connector *connector);
>  
>  #endif /* __INTEL_CONNECTOR_H__ */
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index d70612cc1ba2a..de20effb3e073 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -442,6 +442,23 @@ struct intel_connector {
>  	struct work_struct modeset_retry_work;
>  
>  	struct intel_hdcp hdcp;
> +
> +	/* Optional "privacy-screen" property for the connector panel */
> +	struct drm_property *privacy_screen_property;
> +};
> +
> +/**
> + * enum intel_privacy_screen_status - privacy_screen status
> + *
> + * This enum is used to track and control the state of the integrated privacy
> + * screen present on some display panels, via the "privacy-screen" property.
> + *
> + * @PRIVACY_SCREEN_DISABLED: The privacy-screen on the panel is disabled
> + * @PRIVACY_SCREEN_ENABLED:  The privacy-screen on the panel is enabled
> + **/
> +enum intel_privacy_screen_status {
> +	PRIVACY_SCREEN_DISABLED = 0,
> +	PRIVACY_SCREEN_ENABLED = 1,
>  };
>  
>  struct intel_digital_connector_state {
> @@ -449,6 +466,7 @@ struct intel_digital_connector_state {
>  
>  	enum hdmi_force_audio force_audio;
>  	int broadcast_rgb;
> +	enum intel_privacy_screen_status privacy_screen_status;
>  };
>  
>  #define to_intel_digital_connector_state(x) container_of(x, struct intel_digital_connector_state, base)
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 171821113d362..ff76c799364d0 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -62,6 +62,7 @@
>  #include "intel_lspcon.h"
>  #include "intel_lvds.h"
>  #include "intel_panel.h"
> +#include "intel_privacy_screen.h"
>  #include "intel_psr.h"
>  #include "intel_sideband.h"
>  #include "intel_tc.h"
> @@ -6841,6 +6842,7 @@ intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connect
>  {
>  	struct drm_i915_private *dev_priv = to_i915(connector->dev);
>  	enum port port = dp_to_dig_port(intel_dp)->base.port;
> +	struct intel_connector *intel_connector = to_intel_connector(connector);
>  
>  	if (!IS_G4X(dev_priv) && port != PORT_A)
>  		intel_attach_force_audio_property(connector);
> @@ -6871,6 +6873,10 @@ intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connect
>  
>  		/* Lookup the ACPI node corresponding to the connector */
>  		intel_acpi_device_id_update(dev_priv);
> +
> +		/* Check for integrated Privacy screen support */
> +		if (intel_privacy_screen_present(intel_connector))
> +			intel_attach_privacy_screen_property(connector);

As said in reply to patch 2, we need to figure this part out.

>  	}
>  }
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_privacy_screen.c b/drivers/gpu/drm/i915/display/intel_privacy_screen.c
> new file mode 100644
> index 0000000000000..c8a5b64f94fb7
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/display/intel_privacy_screen.c
> @@ -0,0 +1,72 @@
> +// SPDX-License-Identifier: GPL-2.0 OR MIT
> +/*
> + * Intel ACPI privacy screen code
> + *
> + * Copyright © 2019 Google Inc.
> + */
> +
> +#include <linux/acpi.h>
> +
> +#include "intel_privacy_screen.h"
> +
> +#define CONNECTOR_DSM_REVID 1
> +
> +#define CONNECTOR_DSM_FN_PRIVACY_ENABLE		2
> +#define CONNECTOR_DSM_FN_PRIVACY_DISABLE		3
> +
> +static const guid_t drm_conn_dsm_guid =
> +	GUID_INIT(0xC7033113, 0x8720, 0x4CEB,
> +		  0x90, 0x90, 0x9D, 0x52, 0xB3, 0xE5, 0x2D, 0x73);
> +
> +/* Makes _DSM call to set privacy screen status */
> +static void acpi_privacy_screen_call_dsm(acpi_handle conn_handle, u64 func)
> +{
> +	union acpi_object *obj;
> +
> +	obj = acpi_evaluate_dsm(conn_handle, &drm_conn_dsm_guid,
> +				CONNECTOR_DSM_REVID, func, NULL);
> +	if (!obj) {
> +		DRM_DEBUG_DRIVER("failed to evaluate _DSM for fn %llx\n", func);
> +		return;
> +	}
> +
> +	ACPI_FREE(obj);
> +}
> +
> +void intel_privacy_screen_set_val(struct intel_connector *connector,
> +				  enum intel_privacy_screen_status val)
> +{
> +	acpi_handle acpi_handle = connector->acpi_handle;
> +
> +	if (!acpi_handle)
> +		return;
> +
> +	if (val == PRIVACY_SCREEN_DISABLED)
> +		acpi_privacy_screen_call_dsm(acpi_handle,
> +					     CONNECTOR_DSM_FN_PRIVACY_DISABLE);
> +	else if (val == PRIVACY_SCREEN_ENABLED)
> +		acpi_privacy_screen_call_dsm(acpi_handle,
> +					     CONNECTOR_DSM_FN_PRIVACY_ENABLE);
> +	else
> +		DRM_WARN("%s: Cannot set privacy screen to invalid val %u\n",
> +			 dev_name(connector->base.dev->dev), val);
> +}
> +
> +bool intel_privacy_screen_present(struct intel_connector *connector)
> +{
> +	acpi_handle handle = connector->acpi_handle;
> +
> +	if (!handle)
> +		return false;
> +
> +	if (!acpi_check_dsm(handle, &drm_conn_dsm_guid,
> +			    CONNECTOR_DSM_REVID,
> +			    1 << CONNECTOR_DSM_FN_PRIVACY_ENABLE |
> +			    1 << CONNECTOR_DSM_FN_PRIVACY_DISABLE)) {
> +		DRM_WARN("%s: Odd, connector ACPI node but no privacy scrn?\n",
> +			 dev_name(connector->base.dev->dev));
> +		return false;
> +	}
> +	DRM_DEV_INFO(connector->base.dev->dev, "supports privacy screen\n");
> +	return true;
> +}

I don't have much to say about the ACPI parts, except please use the new
drm_dbg_kms and drm_info helpers for logging.

BR,
Jani.


> diff --git a/drivers/gpu/drm/i915/display/intel_privacy_screen.h b/drivers/gpu/drm/i915/display/intel_privacy_screen.h
> new file mode 100644
> index 0000000000000..74013a7885c70
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/display/intel_privacy_screen.h
> @@ -0,0 +1,27 @@
> +/* SPDX-License-Identifier: GPL-2.0 OR MIT */
> +/*
> + * Copyright © 2019 Google Inc.
> + */
> +
> +#ifndef __DRM_PRIVACY_SCREEN_H__
> +#define __DRM_PRIVACY_SCREEN_H__
> +
> +#include "intel_display_types.h"
> +
> +#ifdef CONFIG_ACPI
> +bool intel_privacy_screen_present(struct intel_connector *connector);
> +void intel_privacy_screen_set_val(struct intel_connector *connector,
> +				  enum intel_privacy_screen_status val);
> +#else
> +static bool intel_privacy_screen_present(struct intel_connector *connector)
> +{
> +	return false;
> +}
> +
> +static void
> +intel_privacy_screen_set_val(struct intel_connector *connector,
> +			     enum intel_privacy_screen_status val)
> +{ }
> +#endif /* CONFIG_ACPI */
> +
> +#endif /* __DRM_PRIVACY_SCREEN_H__ */

-- 
Jani Nikula, Intel Open Source Graphics Center
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Re: [PATCH v6 2/3] drm/i915: Lookup and attach ACPI device node for connectors

[Rajat Jain]

On Thu, Mar 5, 2020 at 1:41 AM Jani Nikula <jani.nikula@linux.intel.com> wrote:
>
> On Wed, 04 Mar 2020, Rajat Jain <rajatja@google.com> wrote:
> > Lookup and attach ACPI nodes for intel connectors. The lookup is done
> > in compliance with ACPI Spec 6.3
> > https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf
> > (Ref: Pages 1119 - 1123).
> >
> > This can be useful for any connector specific platform properties. (This
> > will be used for privacy screen in next patch).
> >
> > Signed-off-by: Rajat Jain <rajatja@google.com>
> > ---
> > v6: Addressed minor comments from Jani at
> >     https://lkml.org/lkml/2020/1/24/1143
> >      - local variable renamed.
> >      - used drm_dbg_kms()
> >      - used acpi_device_handle()
> >      - Used opaque type acpi_handle instead of void*
> > v5: same as v4
> > v4: Same as v3
> > v3: fold the code into existing acpi_device_id_update() function
> > v2: formed by splitting the original patch into ACPI lookup, and privacy
> >     screen property. Also move it into i915 now that I found existing code
> >     in i915 that can be re-used.
> >
> >  drivers/gpu/drm/i915/display/intel_acpi.c     | 24 +++++++++++++++++++
> >  .../drm/i915/display/intel_display_types.h    |  5 ++++
> >  drivers/gpu/drm/i915/display/intel_dp.c       |  3 +++
> >  3 files changed, 32 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_acpi.c b/drivers/gpu/drm/i915/display/intel_acpi.c
> > index 3e6831cca4ac1..870c1ad98df92 100644
> > --- a/drivers/gpu/drm/i915/display/intel_acpi.c
> > +++ b/drivers/gpu/drm/i915/display/intel_acpi.c
> > @@ -222,11 +222,22 @@ static u32 acpi_display_type(struct intel_connector *connector)
> >       return display_type;
> >  }
> >
> > +/*
> > + * Ref: ACPI Spec 6.3
> > + * https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf
> > + * Pages 1119 - 1123 describe, what I believe, a standard way of
> > + * identifying / addressing "display panels" in the ACPI. It provides
> > + * a way for the ACPI to define devices for the display panels attached
> > + * to the system. It thus provides a way for the BIOS to export any panel
> > + * specific properties to the system via ACPI (like device trees).
> > + */
> >  void intel_acpi_device_id_update(struct drm_i915_private *dev_priv)
> >  {
> >       struct drm_device *dev = &dev_priv->drm;
> >       struct intel_connector *connector;
> >       struct drm_connector_list_iter conn_iter;
> > +     struct acpi_device *conn_dev;
> > +     u64 conn_addr;
> >       u8 display_index[16] = {};
> >
> >       /* Populate the ACPI IDs for all connectors for a given drm_device */
> > @@ -242,6 +253,19 @@ void intel_acpi_device_id_update(struct drm_i915_private *dev_priv)
> >               device_id |= display_index[type]++ << ACPI_DISPLAY_INDEX_SHIFT;
> >
> >               connector->acpi_device_id = device_id;
> > +
> > +             /* Build the _ADR to look for */
> > +             conn_addr = device_id | ACPI_DEVICE_ID_SCHEME |
> > +                             ACPI_BIOS_CAN_DETECT;
> > +
> > +             drm_dbg_kms(dev, "Checking connector ACPI node at _ADR=%llX\n",
> > +                         conn_addr);
> > +
> > +             /* Look up the connector device, under the PCI device */
> > +             conn_dev = acpi_find_child_device(
> > +                                     ACPI_COMPANION(&dev->pdev->dev),
> > +                                     conn_addr, false);
> > +             connector->acpi_handle = acpi_device_handle(conn_dev);
> >       }
> >       drm_connector_list_iter_end(&conn_iter);
> >  }
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> > index 5e00e611f077f..d70612cc1ba2a 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> > @@ -411,9 +411,14 @@ struct intel_connector {
> >        */
> >       struct intel_encoder *encoder;
> >
> > +#ifdef CONFIG_ACPI
> >       /* ACPI device id for ACPI and driver cooperation */
> >       u32 acpi_device_id;
> >
> > +     /* ACPI handle corresponding to this connector display, if found */
> > +     acpi_handle acpi_handle;
> > +#endif
> > +
> >       /* Reads out the current hw, returning true if the connector is enabled
> >        * and active (i.e. dpms ON state). */
> >       bool (*get_hw_state)(struct intel_connector *);
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> > index 0a417cd2af2bc..171821113d362 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > @@ -44,6 +44,7 @@
> >  #include "i915_debugfs.h"
> >  #include "i915_drv.h"
> >  #include "i915_trace.h"
> > +#include "intel_acpi.h"
> >  #include "intel_atomic.h"
> >  #include "intel_audio.h"
> >  #include "intel_connector.h"
> > @@ -6868,6 +6869,8 @@ intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connect
> >
> >               connector->state->scaling_mode = DRM_MODE_SCALE_ASPECT;
> >
> > +             /* Lookup the ACPI node corresponding to the connector */
> > +             intel_acpi_device_id_update(dev_priv);
>
> I find this part problematic.
>
> Normally, we call the function at probe via i915_driver_register() ->
> intel_opregion_register() -> intel_opregion_resume() ->
> intel_didl_outputs() -> intel_acpi_device_id_update(). It gets called
> *once* at probe, after we have all the outputs (and thus connectors)
> figured out.
>
> This in turn calls it for every DP connector, before we even have all
> connectors registered. But it also re-iterates the previously handled
> connectors again and again.
>
> The problem, of course, is that you'll need connector->acpi_handle to
> figure out whether the feature is present and whether the property is
> needed. Figuring out acpi_handle also requires
> connector->acpi_device_id.
>
> It's a bit of a catch-22.
>
> I think the options are:
>
> 1) See if we can postpone creating and attaching properties to connector
> ->late_register hook. (I didn't have the time to look into it yet, at
> all.)

Apparently not. The drm core doesn't like to add properties in
late_register() callback. I just tried it and get this warning:

[    1.223163] WARNING: CPU: 2 PID: 1 at
drivers/gpu/drm/drm_mode_object.c:45 __drm_mode_object_add+0xab/0xaf
....
<snip>
.....
[    1.223540] Call Trace:
[    1.223540]  drm_property_create+0xcc/0x155
[    1.223540]  drm_property_create_enum+0x26/0x79
[    1.223540]  intel_attach_privacy_screen_property+0x3a/0x5d
[    1.223540]  intel_dp_connector_register+0x6a/0xa8
[    1.223540]  drm_connector_register+0x61/0xaa
[    1.223540]  drm_connector_register_all+0x46/0x8b
[    1.223540]  drm_modeset_register_all+0x3e/0x67
[    1.223540]  drm_dev_register+0x124/0x187
[    1.223540]  i915_driver_probe+0xa18/0xda0
[    1.223540]  i915_pci_probe+0x145/0x168

>
> 2) Provide a way to populate connector->acpi_device_id and
> connector->acpi_handle on a per-connector basis. At least the device id
> remains constant for the lifetime of the drm_device

Are you confirming that the connector->acpi_device_id remains constant
for the lifetime of the drm_device, as calculated in
intel_acpi_device_id_update()?  Even in the face of external displays
(monitors) being connected and disconnected during the lifetime of the
system? If so, then I think we can have a solution.

> (why do we keep
> updating it at every resume?!) but can we be sure ->acpi_handle does
> too? (I don't really know my way around ACPI.)

I don't understand why this was being updated on every resume in that
case (this existed even before my patchset). I believe we do not need
it. Yes, the ->acpi_handle will not change if the ->acpi_device_id
does not change. I believe the way forward should then be to populate
connector->acpi_device_id and connector->acpi_handle ONE TIME at the
time of connector init (and not update it on every resume). Does this
sound ok?

I can write the code up and send as my next patch iteration.

Thanks,

Rajat

>



> >       }
> >  }
>
> --
> Jani Nikula, Intel Open Source Graphics Center
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Re: [PATCH v6 3/3] drm/i915: Add support for integrated privacy screens

[Rajat Jain]

Hi Jani,

Thank you for the comments. Please see my responses inline.

On Thu, Mar 5, 2020 at 2:02 AM Jani Nikula <jani.nikula@linux.intel.com> wrote:
>
> On Wed, 04 Mar 2020, Rajat Jain <rajatja@google.com> wrote:
> > Certain laptops now come with panels that have integrated privacy
> > screens on them. This patch adds support for such panels by adding
> > a privacy-screen property to the intel_connector for the panel, that
> > the userspace can then use to control and check the status.
> >
> > Identifying the presence of privacy screen, and controlling it, is done
> > via ACPI _DSM methods.
> >
> > Currently, this is done only for the Intel display ports. But in future,
> > this can be done for any other ports if the hardware becomes available
> > (e.g. external monitors supporting integrated privacy screens?).
>
> I think you should add the property at the drm core level in
> drm_connector.c, not in i915, to ensure we have the same property across
> drivers. Even if, for now, you leave the acpi implementation part in
> i915.

OK, will do. In order to do that I may need to introduce driver level
hooks that i915 driver can populate and drm core can call (or may be
some functions to add privacy screen property that drm core exports
and i915 driver will call).

>
> More comments inline.
>
> >
> > Signed-off-by: Rajat Jain <rajatja@google.com>
> > ---
> > v6: Always initialize prop in intel_attach_privacy_screen_property()
> > v5: fix a cosmetic checkpatch warning
> > v4: Fix a typo in intel_privacy_screen.h
> > v3: * Change license to GPL-2.0 OR MIT
> >     * Move privacy screen enum from UAPI to intel_display_types.h
> >     * Rename parameter name and some other minor changes.
> > v2: Formed by splitting the original patch into multiple patches.
> >     - All code has been moved into i915 now.
> >     - Privacy screen is a i915 property
> >     - Have a local state variable to store the prvacy screen. Don't read
> >       it from hardware.
> >
> >  drivers/gpu/drm/i915/Makefile                 |  3 +-
> >  drivers/gpu/drm/i915/display/intel_atomic.c   | 13 +++-
> >  .../gpu/drm/i915/display/intel_connector.c    | 35 +++++++++
> >  .../gpu/drm/i915/display/intel_connector.h    |  1 +
> >  .../drm/i915/display/intel_display_types.h    | 18 +++++
> >  drivers/gpu/drm/i915/display/intel_dp.c       |  6 ++
> >  .../drm/i915/display/intel_privacy_screen.c   | 72 +++++++++++++++++++
> >  .../drm/i915/display/intel_privacy_screen.h   | 27 +++++++
> >  8 files changed, 171 insertions(+), 4 deletions(-)
> >  create mode 100644 drivers/gpu/drm/i915/display/intel_privacy_screen.c
> >  create mode 100644 drivers/gpu/drm/i915/display/intel_privacy_screen.h
> >
> > diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> > index 991a8c537d123..825951b4cd006 100644
> > --- a/drivers/gpu/drm/i915/Makefile
> > +++ b/drivers/gpu/drm/i915/Makefile
> > @@ -208,7 +208,8 @@ i915-y += \
> >       display/intel_vga.o
> >  i915-$(CONFIG_ACPI) += \
> >       display/intel_acpi.o \
> > -     display/intel_opregion.o
> > +     display/intel_opregion.o \
> > +     display/intel_privacy_screen.o
> >  i915-$(CONFIG_DRM_FBDEV_EMULATION) += \
> >       display/intel_fbdev.o
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_atomic.c b/drivers/gpu/drm/i915/display/intel_atomic.c
> > index d043057d2fa03..4ed537c877777 100644
> > --- a/drivers/gpu/drm/i915/display/intel_atomic.c
> > +++ b/drivers/gpu/drm/i915/display/intel_atomic.c
> > @@ -40,6 +40,7 @@
> >  #include "intel_global_state.h"
> >  #include "intel_hdcp.h"
> >  #include "intel_psr.h"
> > +#include "intel_privacy_screen.h"
> >  #include "intel_sprite.h"
> >
> >  /**
> > @@ -60,11 +61,14 @@ int intel_digital_connector_atomic_get_property(struct drm_connector *connector,
> >       struct drm_i915_private *dev_priv = to_i915(dev);
> >       struct intel_digital_connector_state *intel_conn_state =
> >               to_intel_digital_connector_state(state);
> > +     struct intel_connector *intel_connector = to_intel_connector(connector);
> >
> >       if (property == dev_priv->force_audio_property)
> >               *val = intel_conn_state->force_audio;
> >       else if (property == dev_priv->broadcast_rgb_property)
> >               *val = intel_conn_state->broadcast_rgb;
> > +     else if (property == intel_connector->privacy_screen_property)
> > +             *val = intel_conn_state->privacy_screen_status;
> >       else {
> >               drm_dbg_atomic(&dev_priv->drm,
> >                              "Unknown property [PROP:%d:%s]\n",
> > @@ -93,15 +97,18 @@ int intel_digital_connector_atomic_set_property(struct drm_connector *connector,
> >       struct drm_i915_private *dev_priv = to_i915(dev);
> >       struct intel_digital_connector_state *intel_conn_state =
> >               to_intel_digital_connector_state(state);
> > +     struct intel_connector *intel_connector = to_intel_connector(connector);
> >
> >       if (property == dev_priv->force_audio_property) {
> >               intel_conn_state->force_audio = val;
> >               return 0;
> > -     }
> > -
> > -     if (property == dev_priv->broadcast_rgb_property) {
> > +     } else if (property == dev_priv->broadcast_rgb_property) {
> >               intel_conn_state->broadcast_rgb = val;
> >               return 0;
> > +     } else if (property == intel_connector->privacy_screen_property) {
> > +             intel_privacy_screen_set_val(intel_connector, val);
>
> I think this part should only change the connector state. The driver
> would then do the magic at commit stage according to the property value.

Can you please point me to some code reference as to where in code
does the "commit stage" apply the changes?

>
> > +             intel_conn_state->privacy_screen_status = val;
> > +             return 0;
> >       }
> >
> >       drm_dbg_atomic(&dev_priv->drm, "Unknown property [PROP:%d:%s]\n",
> > diff --git a/drivers/gpu/drm/i915/display/intel_connector.c b/drivers/gpu/drm/i915/display/intel_connector.c
> > index 903e49659f561..55f80219cb269 100644
> > --- a/drivers/gpu/drm/i915/display/intel_connector.c
> > +++ b/drivers/gpu/drm/i915/display/intel_connector.c
> > @@ -297,3 +297,38 @@ intel_attach_colorspace_property(struct drm_connector *connector)
> >       drm_object_attach_property(&connector->base,
> >                                  connector->colorspace_property, 0);
> >  }
> > +
> > +static const struct drm_prop_enum_list privacy_screen_enum[] = {
> > +     { PRIVACY_SCREEN_DISABLED, "Disabled" },
> > +     { PRIVACY_SCREEN_ENABLED, "Enabled" },
> > +};
> > +
> > +/**
> > + * intel_attach_privacy_screen_property -
> > + *     create and attach the connecter's privacy-screen property. *
> > + * @connector: connector for which to init the privacy-screen property
> > + *
> > + * This function creates and attaches the "privacy-screen" property to the
> > + * connector. Initial state of privacy-screen is set to disabled.
> > + */
> > +void
> > +intel_attach_privacy_screen_property(struct drm_connector *connector)
> > +{
> > +     struct intel_connector *intel_connector = to_intel_connector(connector);
> > +     struct drm_property *prop = intel_connector->privacy_screen_property;
> > +
> > +     if (!prop) {
> > +             prop = drm_property_create_enum(connector->dev,
> > +                                             DRM_MODE_PROP_ENUM,
> > +                                             "privacy-screen",
> > +                                             privacy_screen_enum,
> > +                                         ARRAY_SIZE(privacy_screen_enum));
> > +             if (!prop)
> > +                     return;
> > +
> > +             intel_connector->privacy_screen_property = prop;
> > +     }
> > +
> > +     drm_object_attach_property(&connector->base, prop,
> > +                                PRIVACY_SCREEN_DISABLED);
> > +}
>
> This looks about right, except IMO should be part of drm_connector and
> moved to drm_connector.c.

Will do.

>
> > diff --git a/drivers/gpu/drm/i915/display/intel_connector.h b/drivers/gpu/drm/i915/display/intel_connector.h
> > index 93a7375c8196d..61005f37a3385 100644
> > --- a/drivers/gpu/drm/i915/display/intel_connector.h
> > +++ b/drivers/gpu/drm/i915/display/intel_connector.h
> > @@ -31,5 +31,6 @@ void intel_attach_force_audio_property(struct drm_connector *connector);
> >  void intel_attach_broadcast_rgb_property(struct drm_connector *connector);
> >  void intel_attach_aspect_ratio_property(struct drm_connector *connector);
> >  void intel_attach_colorspace_property(struct drm_connector *connector);
> > +void intel_attach_privacy_screen_property(struct drm_connector *connector);
> >
> >  #endif /* __INTEL_CONNECTOR_H__ */
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> > index d70612cc1ba2a..de20effb3e073 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> > @@ -442,6 +442,23 @@ struct intel_connector {
> >       struct work_struct modeset_retry_work;
> >
> >       struct intel_hdcp hdcp;
> > +
> > +     /* Optional "privacy-screen" property for the connector panel */
> > +     struct drm_property *privacy_screen_property;
> > +};
> > +
> > +/**
> > + * enum intel_privacy_screen_status - privacy_screen status
> > + *
> > + * This enum is used to track and control the state of the integrated privacy
> > + * screen present on some display panels, via the "privacy-screen" property.
> > + *
> > + * @PRIVACY_SCREEN_DISABLED: The privacy-screen on the panel is disabled
> > + * @PRIVACY_SCREEN_ENABLED:  The privacy-screen on the panel is enabled
> > + **/
> > +enum intel_privacy_screen_status {
> > +     PRIVACY_SCREEN_DISABLED = 0,
> > +     PRIVACY_SCREEN_ENABLED = 1,
> >  };
> >
> >  struct intel_digital_connector_state {
> > @@ -449,6 +466,7 @@ struct intel_digital_connector_state {
> >
> >       enum hdmi_force_audio force_audio;
> >       int broadcast_rgb;
> > +     enum intel_privacy_screen_status privacy_screen_status;
> >  };
> >
> >  #define to_intel_digital_connector_state(x) container_of(x, struct intel_digital_connector_state, base)
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> > index 171821113d362..ff76c799364d0 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > @@ -62,6 +62,7 @@
> >  #include "intel_lspcon.h"
> >  #include "intel_lvds.h"
> >  #include "intel_panel.h"
> > +#include "intel_privacy_screen.h"
> >  #include "intel_psr.h"
> >  #include "intel_sideband.h"
> >  #include "intel_tc.h"
> > @@ -6841,6 +6842,7 @@ intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connect
> >  {
> >       struct drm_i915_private *dev_priv = to_i915(connector->dev);
> >       enum port port = dp_to_dig_port(intel_dp)->base.port;
> > +     struct intel_connector *intel_connector = to_intel_connector(connector);
> >
> >       if (!IS_G4X(dev_priv) && port != PORT_A)
> >               intel_attach_force_audio_property(connector);
> > @@ -6871,6 +6873,10 @@ intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connect
> >
> >               /* Lookup the ACPI node corresponding to the connector */
> >               intel_acpi_device_id_update(dev_priv);
> > +
> > +             /* Check for integrated Privacy screen support */
> > +             if (intel_privacy_screen_present(intel_connector))
> > +                     intel_attach_privacy_screen_property(connector);
>
> As said in reply to patch 2, we need to figure this part out.

Yup, responded in patch 2 reply.

>
> >       }
> >  }
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_privacy_screen.c b/drivers/gpu/drm/i915/display/intel_privacy_screen.c
> > new file mode 100644
> > index 0000000000000..c8a5b64f94fb7
> > --- /dev/null
> > +++ b/drivers/gpu/drm/i915/display/intel_privacy_screen.c
> > @@ -0,0 +1,72 @@
> > +// SPDX-License-Identifier: GPL-2.0 OR MIT
> > +/*
> > + * Intel ACPI privacy screen code
> > + *
> > + * Copyright © 2019 Google Inc.
> > + */
> > +
> > +#include <linux/acpi.h>
> > +
> > +#include "intel_privacy_screen.h"
> > +
> > +#define CONNECTOR_DSM_REVID 1
> > +
> > +#define CONNECTOR_DSM_FN_PRIVACY_ENABLE              2
> > +#define CONNECTOR_DSM_FN_PRIVACY_DISABLE             3
> > +
> > +static const guid_t drm_conn_dsm_guid =
> > +     GUID_INIT(0xC7033113, 0x8720, 0x4CEB,
> > +               0x90, 0x90, 0x9D, 0x52, 0xB3, 0xE5, 0x2D, 0x73);
> > +
> > +/* Makes _DSM call to set privacy screen status */
> > +static void acpi_privacy_screen_call_dsm(acpi_handle conn_handle, u64 func)
> > +{
> > +     union acpi_object *obj;
> > +
> > +     obj = acpi_evaluate_dsm(conn_handle, &drm_conn_dsm_guid,
> > +                             CONNECTOR_DSM_REVID, func, NULL);
> > +     if (!obj) {
> > +             DRM_DEBUG_DRIVER("failed to evaluate _DSM for fn %llx\n", func);
> > +             return;
> > +     }
> > +
> > +     ACPI_FREE(obj);
> > +}
> > +
> > +void intel_privacy_screen_set_val(struct intel_connector *connector,
> > +                               enum intel_privacy_screen_status val)
> > +{
> > +     acpi_handle acpi_handle = connector->acpi_handle;
> > +
> > +     if (!acpi_handle)
> > +             return;
> > +
> > +     if (val == PRIVACY_SCREEN_DISABLED)
> > +             acpi_privacy_screen_call_dsm(acpi_handle,
> > +                                          CONNECTOR_DSM_FN_PRIVACY_DISABLE);
> > +     else if (val == PRIVACY_SCREEN_ENABLED)
> > +             acpi_privacy_screen_call_dsm(acpi_handle,
> > +                                          CONNECTOR_DSM_FN_PRIVACY_ENABLE);
> > +     else
> > +             DRM_WARN("%s: Cannot set privacy screen to invalid val %u\n",
> > +                      dev_name(connector->base.dev->dev), val);
> > +}
> > +
> > +bool intel_privacy_screen_present(struct intel_connector *connector)
> > +{
> > +     acpi_handle handle = connector->acpi_handle;
> > +
> > +     if (!handle)
> > +             return false;
> > +
> > +     if (!acpi_check_dsm(handle, &drm_conn_dsm_guid,
> > +                         CONNECTOR_DSM_REVID,
> > +                         1 << CONNECTOR_DSM_FN_PRIVACY_ENABLE |
> > +                         1 << CONNECTOR_DSM_FN_PRIVACY_DISABLE)) {
> > +             DRM_WARN("%s: Odd, connector ACPI node but no privacy scrn?\n",
> > +                      dev_name(connector->base.dev->dev));
> > +             return false;
> > +     }
> > +     DRM_DEV_INFO(connector->base.dev->dev, "supports privacy screen\n");
> > +     return true;
> > +}
>
> I don't have much to say about the ACPI parts, except please use the new
> drm_dbg_kms and drm_info helpers for logging.

Will do.

Thanks,

Rajat

>
> BR,
> Jani.
>
>
> > diff --git a/drivers/gpu/drm/i915/display/intel_privacy_screen.h b/drivers/gpu/drm/i915/display/intel_privacy_screen.h
> > new file mode 100644
> > index 0000000000000..74013a7885c70
> > --- /dev/null
> > +++ b/drivers/gpu/drm/i915/display/intel_privacy_screen.h
> > @@ -0,0 +1,27 @@
> > +/* SPDX-License-Identifier: GPL-2.0 OR MIT */
> > +/*
> > + * Copyright © 2019 Google Inc.
> > + */
> > +
> > +#ifndef __DRM_PRIVACY_SCREEN_H__
> > +#define __DRM_PRIVACY_SCREEN_H__
> > +
> > +#include "intel_display_types.h"
> > +
> > +#ifdef CONFIG_ACPI
> > +bool intel_privacy_screen_present(struct intel_connector *connector);
> > +void intel_privacy_screen_set_val(struct intel_connector *connector,
> > +                               enum intel_privacy_screen_status val);
> > +#else
> > +static bool intel_privacy_screen_present(struct intel_connector *connector)
> > +{
> > +     return false;
> > +}
> > +
> > +static void
> > +intel_privacy_screen_set_val(struct intel_connector *connector,
> > +                          enum intel_privacy_screen_status val)
> > +{ }
> > +#endif /* CONFIG_ACPI */
> > +
> > +#endif /* __DRM_PRIVACY_SCREEN_H__ */
>
> --
> Jani Nikula, Intel Open Source Graphics Center
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Re: [PATCH v6 2/3] drm/i915: Lookup and attach ACPI device node for connectors

[Jani Nikula]

On Thu, 05 Mar 2020, Rajat Jain <rajatja@google.com> wrote:
> On Thu, Mar 5, 2020 at 1:41 AM Jani Nikula <jani.nikula@linux.intel.com> wrote:
>>
>> On Wed, 04 Mar 2020, Rajat Jain <rajatja@google.com> wrote:
>> 1) See if we can postpone creating and attaching properties to connector
>> ->late_register hook. (I didn't have the time to look into it yet, at
>> all.)
>
> Apparently not. The drm core doesn't like to add properties in
> late_register() callback. I just tried it and get this warning:

I kind of had a feeling this would be the case, thanks for checking.

>> 2) Provide a way to populate connector->acpi_device_id and
>> connector->acpi_handle on a per-connector basis. At least the device id
>> remains constant for the lifetime of the drm_device
>
> Are you confirming that the connector->acpi_device_id remains constant
> for the lifetime of the drm_device, as calculated in
> intel_acpi_device_id_update()?  Even in the face of external displays
> (monitors) being connected and disconnected during the lifetime of the
> system? If so, then I think we can have a solution.

First I thought so. Alas it does not hold for DP MST, where you can have
connectors added and removed dynamically. I think we could ensure they
stay the same for all other connectors though. I'm pretty sure this is
already the case; they get added/removed after all others.

Another thought, from the ACPI perspective, I'm not sure the dynamically
added/removed DP MST connectors should even have acpi handles. But
again, tying all this together with ACPI stuff is not something I am an
expert on.

>> (why do we keep
>> updating it at every resume?!) but can we be sure ->acpi_handle does
>> too? (I don't really know my way around ACPI.)
>
> I don't understand why this was being updated on every resume in that
> case (this existed even before my patchset). I believe we do not need
> it. Yes, the ->acpi_handle will not change if the ->acpi_device_id
> does not change. I believe the way forward should then be to populate
> connector->acpi_device_id and connector->acpi_handle ONE TIME at the
> time of connector init (and not update it on every resume). Does this
> sound ok?

If a DP MST connector gets removed, should the other ACPI display
indexes after that shift, or remain the same? I really don't know.

BR,
Jani.

-- 
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Re: [PATCH v6 3/3] drm/i915: Add support for integrated privacy screens

[Jani Nikula]

On Thu, 05 Mar 2020, Rajat Jain <rajatja@google.com> wrote:
> OK, will do. In order to do that I may need to introduce driver level
> hooks that i915 driver can populate and drm core can call (or may be
> some functions to add privacy screen property that drm core exports
> and i915 driver will call).

The latter. Look at drm_connector_attach_*() functions in
drm_connector.c. i915 (or any other driver) can create and attach the
property as needed. drm_atomic_connector_{get,set}_property in
drm_atomic_uapi.c need to handle the properties, but *only* to get/set
the value in drm_connector_state, nothing more. How that value is
actually used is up to the drivers, but the userspace interface will be
the same instead of being driver specific.

>> > @@ -93,15 +97,18 @@ int intel_digital_connector_atomic_set_property(struct drm_connector *connector,
>> >       struct drm_i915_private *dev_priv = to_i915(dev);
>> >       struct intel_digital_connector_state *intel_conn_state =
>> >               to_intel_digital_connector_state(state);
>> > +     struct intel_connector *intel_connector = to_intel_connector(connector);
>> >
>> >       if (property == dev_priv->force_audio_property) {
>> >               intel_conn_state->force_audio = val;
>> >               return 0;
>> > -     }
>> > -
>> > -     if (property == dev_priv->broadcast_rgb_property) {
>> > +     } else if (property == dev_priv->broadcast_rgb_property) {
>> >               intel_conn_state->broadcast_rgb = val;
>> >               return 0;
>> > +     } else if (property == intel_connector->privacy_screen_property) {
>> > +             intel_privacy_screen_set_val(intel_connector, val);
>>
>> I think this part should only change the connector state. The driver
>> would then do the magic at commit stage according to the property value.

Also, this would be the part that's done in drm core level.

> Can you please point me to some code reference as to where in code
> does the "commit stage" apply the changes?

Look at, say, drm_connector_attach_scaling_mode_property(). In the
getter/setter code it'll just read/change state->scaling_mode. You can
use the value in encoder ->enable, ->disable, and ->update_pipe
hooks. Enable should enable the privacy screen if desired, disable
should probably unconditionally disable the privacy screen while
disabling the display, and update should just change the state according
to the value. Update is called if there isn't a full modeset. (Scaling
mode is a bit more indirect than that, affecting other things in the
encoder ->compute_config hook, leading to similar effects.)

Ville, anything I missed?

BR,
Jani.


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Re: [PATCH v6 3/3] drm/i915: Add support for integrated privacy screens

[Rajat Jain]

Thanks Jani so much for the detailed explanation.

I was able to write the code for this, but I am facing one problem, see below.

On Fri, Mar 6, 2020 at 2:15 AM Jani Nikula <jani.nikula@linux.intel.com> wrote:
>
> On Thu, 05 Mar 2020, Rajat Jain <rajatja@google.com> wrote:
> > OK, will do. In order to do that I may need to introduce driver level
> > hooks that i915 driver can populate and drm core can call (or may be
> > some functions to add privacy screen property that drm core exports
> > and i915 driver will call).
>
> The latter. Look at drm_connector_attach_*() functions in
> drm_connector.c. i915 (or any other driver) can create and attach the
> property as needed. drm_atomic_connector_{get,set}_property in
> drm_atomic_uapi.c need to handle the properties, but *only* to get/set
> the value in drm_connector_state, nothing more. How that value is
> actually used is up to the drivers, but the userspace interface will be
> the same instead of being driver specific.

Understood, done.

>
> >> > @@ -93,15 +97,18 @@ int intel_digital_connector_atomic_set_property(struct drm_connector *connector,
> >> >       struct drm_i915_private *dev_priv = to_i915(dev);
> >> >       struct intel_digital_connector_state *intel_conn_state =
> >> >               to_intel_digital_connector_state(state);
> >> > +     struct intel_connector *intel_connector = to_intel_connector(connector);
> >> >
> >> >       if (property == dev_priv->force_audio_property) {
> >> >               intel_conn_state->force_audio = val;
> >> >               return 0;
> >> > -     }
> >> > -
> >> > -     if (property == dev_priv->broadcast_rgb_property) {
> >> > +     } else if (property == dev_priv->broadcast_rgb_property) {
> >> >               intel_conn_state->broadcast_rgb = val;
> >> >               return 0;
> >> > +     } else if (property == intel_connector->privacy_screen_property) {
> >> > +             intel_privacy_screen_set_val(intel_connector, val);
> >>
> >> I think this part should only change the connector state. The driver
> >> would then do the magic at commit stage according to the property value.
>
> Also, this would be the part that's done in drm core level.
>

Yup.

> > Can you please point me to some code reference as to where in code
> > does the "commit stage" apply the changes?
>
> Look at, say, drm_connector_attach_scaling_mode_property(). In the
> getter/setter code it'll just read/change state->scaling_mode. You can
> use the value in encoder ->enable, ->disable, and ->update_pipe
> hooks. Enable should enable the privacy screen if desired, disable
> should probably unconditionally disable the privacy screen while
> disabling the display, and update should just change the state according
> to the value. Update is called if there isn't a full modeset. (Scaling
> mode is a bit more indirect than that, affecting other things in the
> encoder ->compute_config hook, leading to similar effects.)

For my testing purposes, I'm testing this using the proptest utility
in our distribution (I think from
https://github.com/CPFL/drm/blob/master/tests/proptest/proptest.c). I
notice that when I change the value of the property from userspace,
even though the drm_connector_state->privacy_screen_status gets
updated and reflects the change, the encoder->update_pipe() is not
getting called. Just wanted to ask if this is expected since you seem
to imply this update_pipe() might *not* get called if there *is* a
full modeset? (What is the hook that gets called for a full modeset
where i915 driver should commit this property change to the hardware?)

Thanks & Best Regards,

Rajat


>
> Ville, anything I missed?
>
> BR,
> Jani.
>
>
> --
> Jani Nikula, Intel Open Source Graphics Center
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Re: [PATCH v6 2/3] drm/i915: Lookup and attach ACPI device node for connectors

[Rajat Jain]

On Fri, Mar 6, 2020 at 1:42 AM Jani Nikula <jani.nikula@linux.intel.com> wrote:
>
> On Thu, 05 Mar 2020, Rajat Jain <rajatja@google.com> wrote:
> > On Thu, Mar 5, 2020 at 1:41 AM Jani Nikula <jani.nikula@linux.intel.com> wrote:
> >>
> >> On Wed, 04 Mar 2020, Rajat Jain <rajatja@google.com> wrote:
> >> 1) See if we can postpone creating and attaching properties to connector
> >> ->late_register hook. (I didn't have the time to look into it yet, at
> >> all.)
> >
> > Apparently not. The drm core doesn't like to add properties in
> > late_register() callback. I just tried it and get this warning:
>
> I kind of had a feeling this would be the case, thanks for checking.

Thinking about it again, it looks like there is a difference in
creating a property and attaching a property. I'm wondering if drm
would let me (unconditionally) create a property before registering,
and attach it in late_register() only in case a privacy screen is
detected. (If not present, I can destroy the property in
late_register()). If this approach sound more promising, I can try it
out.

>
> >> 2) Provide a way to populate connector->acpi_device_id and
> >> connector->acpi_handle on a per-connector basis. At least the device id
> >> remains constant for the lifetime of the drm_device
> >
> > Are you confirming that the connector->acpi_device_id remains constant
> > for the lifetime of the drm_device, as calculated in
> > intel_acpi_device_id_update()?  Even in the face of external displays
> > (monitors) being connected and disconnected during the lifetime of the
> > system? If so, then I think we can have a solution.
>
> First I thought so. Alas it does not hold for DP MST, where you can have
> connectors added and removed dynamically. I think we could ensure they
> stay the same for all other connectors though. I'm pretty sure this is
> already the case; they get added/removed after all others.
>
> Another thought, from the ACPI perspective, I'm not sure the dynamically
> added/removed DP MST connectors should even have acpi handles. But
> again, tying all this together with ACPI stuff is not something I am an
> expert on.

I propose that we:

1) Maintain a display_index[] array within the drm_dev, and increment
as connectors are added.
2) Initialize connector->acpi_device_id and and connector->acpi_handle
while registering (one time per connector).
3) Remove the code to update acpi_device_id on every resume.

It doesn't look like anyone on the DP MST side has cared for ACPI so
far, so I doubt if we can do anything that might break MST currently.
In other words, the above should not make things any worse for MST, if
not better. For connectors other than MST, this should allow them to
get ACPI handle and play with it, if they need.

WDYT?

Thanks,

Rajat

>
> >> (why do we keep
> >> updating it at every resume?!) but can we be sure ->acpi_handle does
> >> too? (I don't really know my way around ACPI.)
> >
> > I don't understand why this was being updated on every resume in that
> > case (this existed even before my patchset). I believe we do not need
> > it. Yes, the ->acpi_handle will not change if the ->acpi_device_id
> > does not change. I believe the way forward should then be to populate
> > connector->acpi_device_id and connector->acpi_handle ONE TIME at the
> > time of connector init (and not update it on every resume). Does this
> > sound ok?
>
> If a DP MST connector gets removed, should the other ACPI display
> indexes after that shift, or remain the same? I really don't know.
>
> BR,
> Jani.
>
> --
> Jani Nikula, Intel Open Source Graphics Center
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Re: [PATCH v6 2/3] drm/i915: Lookup and attach ACPI device node for connectors

[Rajat Jain]

On Fri, Mar 6, 2020 at 5:38 PM Rajat Jain <rajatja@google.com> wrote:
>
> On Fri, Mar 6, 2020 at 1:42 AM Jani Nikula <jani.nikula@linux.intel.com> wrote:
> >
> > On Thu, 05 Mar 2020, Rajat Jain <rajatja@google.com> wrote:
> > > On Thu, Mar 5, 2020 at 1:41 AM Jani Nikula <jani.nikula@linux.intel.com> wrote:
> > >>
> > >> On Wed, 04 Mar 2020, Rajat Jain <rajatja@google.com> wrote:
> > >> 1) See if we can postpone creating and attaching properties to connector
> > >> ->late_register hook. (I didn't have the time to look into it yet, at
> > >> all.)
> > >
> > > Apparently not. The drm core doesn't like to add properties in
> > > late_register() callback. I just tried it and get this warning:
> >
> > I kind of had a feeling this would be the case, thanks for checking.
>
> Thinking about it again, it looks like there is a difference in
> creating a property and attaching a property. I'm wondering if drm
> would let me (unconditionally) create a property before registering,
> and attach it in late_register() only in case a privacy screen is
> detected. (If not present, I can destroy the property in
> late_register()). If this approach sound more promising, I can try it
> out.

I tried out this approach, and it worked. The new patchset is posted at:

https://patchwork.freedesktop.org/series/74473/#rev1

Thanks!

Rajat

>
> >
> > >> 2) Provide a way to populate connector->acpi_device_id and
> > >> connector->acpi_handle on a per-connector basis. At least the device id
> > >> remains constant for the lifetime of the drm_device
> > >
> > > Are you confirming that the connector->acpi_device_id remains constant
> > > for the lifetime of the drm_device, as calculated in
> > > intel_acpi_device_id_update()?  Even in the face of external displays
> > > (monitors) being connected and disconnected during the lifetime of the
> > > system? If so, then I think we can have a solution.
> >
> > First I thought so. Alas it does not hold for DP MST, where you can have
> > connectors added and removed dynamically. I think we could ensure they
> > stay the same for all other connectors though. I'm pretty sure this is
> > already the case; they get added/removed after all others.
> >
> > Another thought, from the ACPI perspective, I'm not sure the dynamically
> > added/removed DP MST connectors should even have acpi handles. But
> > again, tying all this together with ACPI stuff is not something I am an
> > expert on.
>
> I propose that we:
>
> 1) Maintain a display_index[] array within the drm_dev, and increment
> as connectors are added.
> 2) Initialize connector->acpi_device_id and and connector->acpi_handle
> while registering (one time per connector).
> 3) Remove the code to update acpi_device_id on every resume.
>
> It doesn't look like anyone on the DP MST side has cared for ACPI so
> far, so I doubt if we can do anything that might break MST currently.
> In other words, the above should not make things any worse for MST, if
> not better. For connectors other than MST, this should allow them to
> get ACPI handle and play with it, if they need.
>
> WDYT?
>
> Thanks,
>
> Rajat
>
> >
> > >> (why do we keep
> > >> updating it at every resume?!) but can we be sure ->acpi_handle does
> > >> too? (I don't really know my way around ACPI.)
> > >
> > > I don't understand why this was being updated on every resume in that
> > > case (this existed even before my patchset). I believe we do not need
> > > it. Yes, the ->acpi_handle will not change if the ->acpi_device_id
> > > does not change. I believe the way forward should then be to populate
> > > connector->acpi_device_id and connector->acpi_handle ONE TIME at the
> > > time of connector init (and not update it on every resume). Does this
> > > sound ok?
> >
> > If a DP MST connector gets removed, should the other ACPI display
> > indexes after that shift, or remain the same? I really don't know.
> >
> > BR,
> > Jani.
> >
> > --
> > Jani Nikula, Intel Open Source Graphics Center
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[PATCH v6 3/3] drm/i915: Add support for integrated privacy screens

[Rajat Jain]

Certain laptops now come with panels that have integrated privacy
screens on them. This patch adds support for such panels by adding
a privacy-screen property to the intel_connector for the panel, that
the userspace can then use to control and check the status.

Identifying the presence of privacy screen, and controlling it, is done
via ACPI _DSM methods.

Currently, this is done only for the Intel display ports. But in future,
this can be done for any other ports if the hardware becomes available
(e.g. external monitors supporting integrated privacy screens?).

Signed-off-by: Rajat Jain <rajatja@google.com>
---
v6: Always initialize prop in intel_attach_privacy_screen_property()
v5: fix a cosmetic checkpatch warning
v4: Fix a typo in intel_privacy_screen.h
v3: * Change license to GPL-2.0 OR MIT
    * Move privacy screen enum from UAPI to intel_display_types.h
    * Rename parameter name and some other minor changes.
v2: Formed by splitting the original patch into multiple patches.
    - All code has been moved into i915 now.
    - Privacy screen is a i915 property
    - Have a local state variable to store the prvacy screen. Don't read
      it from hardware.

 drivers/gpu/drm/i915/Makefile                 |  3 +-
 drivers/gpu/drm/i915/display/intel_atomic.c   | 13 +++-
 .../gpu/drm/i915/display/intel_connector.c    | 35 +++++++++
 .../gpu/drm/i915/display/intel_connector.h    |  1 +
 .../drm/i915/display/intel_display_types.h    | 18 +++++
 drivers/gpu/drm/i915/display/intel_dp.c       |  6 ++
 .../drm/i915/display/intel_privacy_screen.c   | 72 +++++++++++++++++++
 .../drm/i915/display/intel_privacy_screen.h   | 27 +++++++
 8 files changed, 171 insertions(+), 4 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/display/intel_privacy_screen.c
 create mode 100644 drivers/gpu/drm/i915/display/intel_privacy_screen.h

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 991a8c537d123..825951b4cd006 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -208,7 +208,8 @@ i915-y += \
 	display/intel_vga.o
 i915-$(CONFIG_ACPI) += \
 	display/intel_acpi.o \
-	display/intel_opregion.o
+	display/intel_opregion.o \
+	display/intel_privacy_screen.o
 i915-$(CONFIG_DRM_FBDEV_EMULATION) += \
 	display/intel_fbdev.o
 
diff --git a/drivers/gpu/drm/i915/display/intel_atomic.c b/drivers/gpu/drm/i915/display/intel_atomic.c
index d043057d2fa03..4ed537c877777 100644
--- a/drivers/gpu/drm/i915/display/intel_atomic.c
+++ b/drivers/gpu/drm/i915/display/intel_atomic.c
@@ -40,6 +40,7 @@
 #include "intel_global_state.h"
 #include "intel_hdcp.h"
 #include "intel_psr.h"
+#include "intel_privacy_screen.h"
 #include "intel_sprite.h"
 
 /**
@@ -60,11 +61,14 @@ int intel_digital_connector_atomic_get_property(struct drm_connector *connector,
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	struct intel_digital_connector_state *intel_conn_state =
 		to_intel_digital_connector_state(state);
+	struct intel_connector *intel_connector = to_intel_connector(connector);
 
 	if (property == dev_priv->force_audio_property)
 		*val = intel_conn_state->force_audio;
 	else if (property == dev_priv->broadcast_rgb_property)
 		*val = intel_conn_state->broadcast_rgb;
+	else if (property == intel_connector->privacy_screen_property)
+		*val = intel_conn_state->privacy_screen_status;
 	else {
 		drm_dbg_atomic(&dev_priv->drm,
 			       "Unknown property [PROP:%d:%s]\n",
@@ -93,15 +97,18 @@ int intel_digital_connector_atomic_set_property(struct drm_connector *connector,
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	struct intel_digital_connector_state *intel_conn_state =
 		to_intel_digital_connector_state(state);
+	struct intel_connector *intel_connector = to_intel_connector(connector);
 
 	if (property == dev_priv->force_audio_property) {
 		intel_conn_state->force_audio = val;
 		return 0;
-	}
-
-	if (property == dev_priv->broadcast_rgb_property) {
+	} else if (property == dev_priv->broadcast_rgb_property) {
 		intel_conn_state->broadcast_rgb = val;
 		return 0;
+	} else if (property == intel_connector->privacy_screen_property) {
+		intel_privacy_screen_set_val(intel_connector, val);
+		intel_conn_state->privacy_screen_status = val;
+		return 0;
 	}
 
 	drm_dbg_atomic(&dev_priv->drm, "Unknown property [PROP:%d:%s]\n",
diff --git a/drivers/gpu/drm/i915/display/intel_connector.c b/drivers/gpu/drm/i915/display/intel_connector.c
index 903e49659f561..55f80219cb269 100644
--- a/drivers/gpu/drm/i915/display/intel_connector.c
+++ b/drivers/gpu/drm/i915/display/intel_connector.c
@@ -297,3 +297,38 @@ intel_attach_colorspace_property(struct drm_connector *connector)
 	drm_object_attach_property(&connector->base,
 				   connector->colorspace_property, 0);
 }
+
+static const struct drm_prop_enum_list privacy_screen_enum[] = {
+	{ PRIVACY_SCREEN_DISABLED, "Disabled" },
+	{ PRIVACY_SCREEN_ENABLED, "Enabled" },
+};
+
+/**
+ * intel_attach_privacy_screen_property -
+ *     create and attach the connecter's privacy-screen property. *
+ * @connector: connector for which to init the privacy-screen property
+ *
+ * This function creates and attaches the "privacy-screen" property to the
+ * connector. Initial state of privacy-screen is set to disabled.
+ */
+void
+intel_attach_privacy_screen_property(struct drm_connector *connector)
+{
+	struct intel_connector *intel_connector = to_intel_connector(connector);
+	struct drm_property *prop = intel_connector->privacy_screen_property;
+
+	if (!prop) {
+		prop = drm_property_create_enum(connector->dev,
+						DRM_MODE_PROP_ENUM,
+						"privacy-screen",
+						privacy_screen_enum,
+					    ARRAY_SIZE(privacy_screen_enum));
+		if (!prop)
+			return;
+
+		intel_connector->privacy_screen_property = prop;
+	}
+
+	drm_object_attach_property(&connector->base, prop,
+				   PRIVACY_SCREEN_DISABLED);
+}
diff --git a/drivers/gpu/drm/i915/display/intel_connector.h b/drivers/gpu/drm/i915/display/intel_connector.h
index 93a7375c8196d..61005f37a3385 100644
--- a/drivers/gpu/drm/i915/display/intel_connector.h
+++ b/drivers/gpu/drm/i915/display/intel_connector.h
@@ -31,5 +31,6 @@ void intel_attach_force_audio_property(struct drm_connector *connector);
 void intel_attach_broadcast_rgb_property(struct drm_connector *connector);
 void intel_attach_aspect_ratio_property(struct drm_connector *connector);
 void intel_attach_colorspace_property(struct drm_connector *connector);
+void intel_attach_privacy_screen_property(struct drm_connector *connector);
 
 #endif /* __INTEL_CONNECTOR_H__ */
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index d70612cc1ba2a..de20effb3e073 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -442,6 +442,23 @@ struct intel_connector {
 	struct work_struct modeset_retry_work;
 
 	struct intel_hdcp hdcp;
+
+	/* Optional "privacy-screen" property for the connector panel */
+	struct drm_property *privacy_screen_property;
+};
+
+/**
+ * enum intel_privacy_screen_status - privacy_screen status
+ *
+ * This enum is used to track and control the state of the integrated privacy
+ * screen present on some display panels, via the "privacy-screen" property.
+ *
+ * @PRIVACY_SCREEN_DISABLED: The privacy-screen on the panel is disabled
+ * @PRIVACY_SCREEN_ENABLED:  The privacy-screen on the panel is enabled
+ **/
+enum intel_privacy_screen_status {
+	PRIVACY_SCREEN_DISABLED = 0,
+	PRIVACY_SCREEN_ENABLED = 1,
 };
 
 struct intel_digital_connector_state {
@@ -449,6 +466,7 @@ struct intel_digital_connector_state {
 
 	enum hdmi_force_audio force_audio;
 	int broadcast_rgb;
+	enum intel_privacy_screen_status privacy_screen_status;
 };
 
 #define to_intel_digital_connector_state(x) container_of(x, struct intel_digital_connector_state, base)
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 171821113d362..ff76c799364d0 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -62,6 +62,7 @@
 #include "intel_lspcon.h"
 #include "intel_lvds.h"
 #include "intel_panel.h"
+#include "intel_privacy_screen.h"
 #include "intel_psr.h"
 #include "intel_sideband.h"
 #include "intel_tc.h"
@@ -6841,6 +6842,7 @@ intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connect
 {
 	struct drm_i915_private *dev_priv = to_i915(connector->dev);
 	enum port port = dp_to_dig_port(intel_dp)->base.port;
+	struct intel_connector *intel_connector = to_intel_connector(connector);
 
 	if (!IS_G4X(dev_priv) && port != PORT_A)
 		intel_attach_force_audio_property(connector);
@@ -6871,6 +6873,10 @@ intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connect
 
 		/* Lookup the ACPI node corresponding to the connector */
 		intel_acpi_device_id_update(dev_priv);
+
+		/* Check for integrated Privacy screen support */
+		if (intel_privacy_screen_present(intel_connector))
+			intel_attach_privacy_screen_property(connector);
 	}
 }
 
diff --git a/drivers/gpu/drm/i915/display/intel_privacy_screen.c b/drivers/gpu/drm/i915/display/intel_privacy_screen.c
new file mode 100644
index 0000000000000..c8a5b64f94fb7
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_privacy_screen.c
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+/*
+ * Intel ACPI privacy screen code
+ *
+ * Copyright © 2019 Google Inc.
+ */
+
+#include <linux/acpi.h>
+
+#include "intel_privacy_screen.h"
+
+#define CONNECTOR_DSM_REVID 1
+
+#define CONNECTOR_DSM_FN_PRIVACY_ENABLE		2
+#define CONNECTOR_DSM_FN_PRIVACY_DISABLE		3
+
+static const guid_t drm_conn_dsm_guid =
+	GUID_INIT(0xC7033113, 0x8720, 0x4CEB,
+		  0x90, 0x90, 0x9D, 0x52, 0xB3, 0xE5, 0x2D, 0x73);
+
+/* Makes _DSM call to set privacy screen status */
+static void acpi_privacy_screen_call_dsm(acpi_handle conn_handle, u64 func)
+{
+	union acpi_object *obj;
+
+	obj = acpi_evaluate_dsm(conn_handle, &drm_conn_dsm_guid,
+				CONNECTOR_DSM_REVID, func, NULL);
+	if (!obj) {
+		DRM_DEBUG_DRIVER("failed to evaluate _DSM for fn %llx\n", func);
+		return;
+	}
+
+	ACPI_FREE(obj);
+}
+
+void intel_privacy_screen_set_val(struct intel_connector *connector,
+				  enum intel_privacy_screen_status val)
+{
+	acpi_handle acpi_handle = connector->acpi_handle;
+
+	if (!acpi_handle)
+		return;
+
+	if (val == PRIVACY_SCREEN_DISABLED)
+		acpi_privacy_screen_call_dsm(acpi_handle,
+					     CONNECTOR_DSM_FN_PRIVACY_DISABLE);
+	else if (val == PRIVACY_SCREEN_ENABLED)
+		acpi_privacy_screen_call_dsm(acpi_handle,
+					     CONNECTOR_DSM_FN_PRIVACY_ENABLE);
+	else
+		DRM_WARN("%s: Cannot set privacy screen to invalid val %u\n",
+			 dev_name(connector->base.dev->dev), val);
+}
+
+bool intel_privacy_screen_present(struct intel_connector *connector)
+{
+	acpi_handle handle = connector->acpi_handle;
+
+	if (!handle)
+		return false;
+
+	if (!acpi_check_dsm(handle, &drm_conn_dsm_guid,
+			    CONNECTOR_DSM_REVID,
+			    1 << CONNECTOR_DSM_FN_PRIVACY_ENABLE |
+			    1 << CONNECTOR_DSM_FN_PRIVACY_DISABLE)) {
+		DRM_WARN("%s: Odd, connector ACPI node but no privacy scrn?\n",
+			 dev_name(connector->base.dev->dev));
+		return false;
+	}
+	DRM_DEV_INFO(connector->base.dev->dev, "supports privacy screen\n");
+	return true;
+}
diff --git a/drivers/gpu/drm/i915/display/intel_privacy_screen.h b/drivers/gpu/drm/i915/display/intel_privacy_screen.h
new file mode 100644
index 0000000000000..74013a7885c70
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_privacy_screen.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 OR MIT */
+/*
+ * Copyright © 2019 Google Inc.
+ */
+
+#ifndef __DRM_PRIVACY_SCREEN_H__
+#define __DRM_PRIVACY_SCREEN_H__
+
+#include "intel_display_types.h"
+
+#ifdef CONFIG_ACPI
+bool intel_privacy_screen_present(struct intel_connector *connector);
+void intel_privacy_screen_set_val(struct intel_connector *connector,
+				  enum intel_privacy_screen_status val);
+#else
+static bool intel_privacy_screen_present(struct intel_connector *connector)
+{
+	return false;
+}
+
+static void
+intel_privacy_screen_set_val(struct intel_connector *connector,
+			     enum intel_privacy_screen_status val)
+{ }
+#endif /* CONFIG_ACPI */
+
+#endif /* __DRM_PRIVACY_SCREEN_H__ */
-- 
2.25.0.265.gbab2e86ba0-goog

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