Re: [v5,3/3] drm/i915: Add support for integrated privacy screens

[Rajat Jain <rajatja@google.com>]

On Fri, Jan 24, 2020 at 4:11 PM Guenter Roeck <linux@roeck-us.net> wrote:
>
> On Fri, Dec 20, 2019 at 12:03:53PM -0800, Rajat Jain 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@google.com>
> > ---
> > 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 90dcf09f52cc..f7067c8f0407 100644
> > --- a/drivers/gpu/drm/i915/Makefile
> > +++ b/drivers/gpu/drm/i915/Makefile
> > @@ -197,7 +197,8 @@ 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 c2875b10adf9..c73b81c4c3f6 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 1133c4e97bb4..f3e041c737de 100644
> > --- a/drivers/gpu/drm/i915/display/intel_connector.c
> > +++ b/drivers/gpu/drm/i915/display/intel_connector.c
> > @@ -296,3 +296,38 @@ 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);
>
> If intel_connector->privacy_screen_property is not NULL, prop
> will be undefined, causing all kinds of fun.

Thank you for catching this. I will fix this in my next iteration.

Thanks,

Rajat

>
> I would expect this to happen whenever this function is called
> for the second time.
>
> Guenter
>
> > +}
> > 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 0a4a04116091..a0addd2c5376 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> > @@ -433,6 +433,23 @@ 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 {
> > @@ -440,6 +457,7 @@ 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 93cece8e2516..d5376d667929 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"
> > @@ -6596,6 +6597,7 @@ 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);
> > @@ -6626,6 +6628,10 @@ 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 000000000000..c8a5b64f94fb
> > --- /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 000000000000..74013a7885c7
> > --- /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__ */