Re: [PATCH v2 3/3] drm/i915: Add support for integrated privacy screens

From: Jani Nikula
Date: Wed Nov 20 2019 - 10:04:35 EST

On Mon, 04 Nov 2019, Rajat Jain <rajatja@xxxxxxxxxx> 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?).
>
> Signed-off-by: Rajat Jain <rajatja@xxxxxxxxxx>
> Change-Id: Ic9ff07fc4a50797d2d0dfb919f11aa0821a4b548
> ---
> 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 | 4 ++
> drivers/gpu/drm/i915/display/intel_dp.c | 5 ++
> .../drm/i915/display/intel_privacy_screen.c | 70 +++++++++++++++++++
> .../drm/i915/display/intel_privacy_screen.h | 25 +++++++
> include/uapi/drm/i915_drm.h | 14 ++++
> 9 files changed, 166 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 2587ea834f06..3589ebcf27bc 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -185,7 +185,8 @@ i915-y += \
> display/intel_tc.o
> i915-$(CONFIG_ACPI) += \
> display/intel_acpi.o \
> - display/intel_opregion.o
> + display/intel_opregion.o \
> + display/intel_privacy_screen.o

Mmmh, wonder if there'll be non-ACPI based privacy screens. I guess we
can sort this out then. *shrug*

> 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 d3fb75bb9eb1..378772d3449c 100644
> --- a/drivers/gpu/drm/i915/display/intel_atomic.c
> +++ b/drivers/gpu/drm/i915/display/intel_atomic.c
> @@ -37,6 +37,7 @@
> #include "intel_atomic.h"
> #include "intel_display_types.h"
> #include "intel_hdcp.h"
> +#include "intel_privacy_screen.h"
> #include "intel_sprite.h"
>
> /**
> @@ -57,11 +58,14 @@ 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_DEBUG_ATOMIC("Unknown property [PROP:%d:%s]\n",
> property->base.id, property->name);
> @@ -89,15 +93,18 @@ 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_DEBUG_ATOMIC("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 308ec63207ee..3ccbf52aedf9 100644
> --- a/drivers/gpu/drm/i915/display/intel_connector.c
> +++ b/drivers/gpu/drm/i915/display/intel_connector.c
> @@ -281,3 +281,38 @@ 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;
> +
> + if (!intel_connector->privacy_screen_property) {
> + 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);
> +}

I think this should be a drm core level property in drm_connector.[ch]
so that *all* drivers would use the same thing for privacy screens. Not
i915 specific.

I think this is the biggest issue in the patch series.

> diff --git a/drivers/gpu/drm/i915/display/intel_connector.h b/drivers/gpu/drm/i915/display/intel_connector.h
> index 93a7375c8196..61005f37a338 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 c2706afc069b..83b8c98049a7 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -426,6 +426,9 @@ 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;
> };
>
> struct intel_digital_connector_state {
> @@ -433,6 +436,7 @@ 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 4fac408a4299..1963e92404ba 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"
> @@ -6358,6 +6359,10 @@ intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connect
>
> /* Lookup the ACPI node corresponding to the connector */
> intel_connector_lookup_acpi_node(intel_connector);
> +
> + /* 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 000000000000..4c422e38c51a
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/display/intel_privacy_screen.c
> @@ -0,0 +1,70 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later

Please read http://mid.mail-archive.com/CAKMK7uH-8+tbKsAoiChsxELEc_77RVVxP2wapHWhqB+0Viifog@xxxxxxxxxxxxxx

> +/*
> + * 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 *intel_connector,
> + enum intel_privacy_screen_status val)

Just name the parameter connector, not intel_connector. This throughout.

> +{
> + acpi_handle acpi_handle = intel_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 complain?

> +}
> +
> +bool intel_privacy_screen_present(struct intel_connector *intel_connector)
> +{
> + acpi_handle handle = intel_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(intel_connector->base.dev->dev));
> + return false;
> + }
> + DRM_DEV_INFO(intel_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 000000000000..212f73349a00
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/display/intel_privacy_screen.h
> @@ -0,0 +1,25 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * 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 *intel_connector);
> +void intel_privacy_screen_set_val(struct intel_connector *intel_connector,
> + enum intel_privacy_screen_status val);
> +#else
> +bool intel_privacy_screen_present(struct intel_connector *intel_connector);
> +{
> + return false;
> +}
> +void intel_privacy_screen_set_val(struct intel_connector *intel_connector,
> + enum intel_privacy_screen_status val)
> +{ }
> +#endif /* CONFIG_ACPI */
> +
> +#endif /* __DRM_PRIVACY_SCREEN_H__ */
> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index 469dc512cca3..cf08d5636363 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -2123,6 +2123,20 @@ struct drm_i915_query_engine_info {
> struct drm_i915_engine_info engines[];
> };
>
> +/**
> + * 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,
> +};
> +

The drm_property interface UAPI is based on the strings, *not* on the
values. Please move the enum out of uapi into the drm code.

BR,
jani.

> #if defined(__cplusplus)
> }
> #endif

--
Jani Nikula, Intel Open Source Graphics Center