drm/privacy-screen: Add X86 specific arch init code

Add X86 specific arch init code, which fills the privacy-screen lookup
table by checking for various vendor specific ACPI interfaces for
controlling the privacy-screen.

This initial version only checks for the Lenovo Thinkpad specific ACPI
methods for privacy-screen control.

Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211005202322.700909-4-hdegoede@redhat.com

diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 788fc37..12997ca 100644 (file)
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -32,7 +32,7 @@ drm-$(CONFIG_OF) += drm_of.o
 drm-$(CONFIG_PCI) += drm_pci.o
 drm-$(CONFIG_DEBUG_FS) += drm_debugfs.o drm_debugfs_crc.o
 drm-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
-drm-$(CONFIG_DRM_PRIVACY_SCREEN) += drm_privacy_screen.o
+drm-$(CONFIG_DRM_PRIVACY_SCREEN) += drm_privacy_screen.o drm_privacy_screen_x86.o
 
 obj-$(CONFIG_DRM_DP_AUX_BUS) += drm_dp_aux_bus.o
 

diff --git a/drivers/gpu/drm/drm_privacy_screen_x86.c b/drivers/gpu/drm/drm_privacy_screen_x86.c
new file mode 100644 (file)
index 0000000..a2cafb2
--- /dev/null
+++ b/drivers/gpu/drm/drm_privacy_screen_x86.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright (C) 2020 Red Hat, Inc.
+ *
+ * Authors:
+ * Hans de Goede <hdegoede@redhat.com>
+ */
+
+#include <linux/acpi.h>
+#include <drm/drm_privacy_screen_machine.h>
+
+#ifdef CONFIG_X86
+static struct drm_privacy_screen_lookup arch_lookup;
+
+struct arch_init_data {
+       struct drm_privacy_screen_lookup lookup;
+       bool (*detect)(void);
+};
+
+#if IS_ENABLED(CONFIG_THINKPAD_ACPI)
+static acpi_status __init acpi_set_handle(acpi_handle handle, u32 level,
+                                         void *context, void **return_value)
+{
+       *(acpi_handle *)return_value = handle;
+       return AE_CTRL_TERMINATE;
+}
+
+static bool __init detect_thinkpad_privacy_screen(void)
+{
+       union acpi_object obj = { .type = ACPI_TYPE_INTEGER };
+       struct acpi_object_list args = { .count = 1, .pointer = &obj, };
+       acpi_handle ec_handle = NULL;
+       unsigned long long output;
+       acpi_status status;
+
+       /* Get embedded-controller handle */
+       status = acpi_get_devices("PNP0C09", acpi_set_handle, NULL, &ec_handle);
+       if (ACPI_FAILURE(status) || !ec_handle)
+               return false;
+
+       /* And call the privacy-screen get-status method */
+       status = acpi_evaluate_integer(ec_handle, "HKEY.GSSS", &args, &output);
+       if (ACPI_FAILURE(status))
+               return false;
+
+       return (output & 0x10000) ? true : false;
+}
+#endif
+
+static const struct arch_init_data arch_init_data[] __initconst = {
+#if IS_ENABLED(CONFIG_THINKPAD_ACPI)
+       {
+               .lookup = {
+                       .dev_id = NULL,
+                       .con_id = NULL,
+                       .provider = "privacy_screen-thinkpad_acpi",
+               },
+               .detect = detect_thinkpad_privacy_screen,
+       },
+#endif
+};
+
+void __init drm_privacy_screen_lookup_init(void)
+{
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(arch_init_data); i++) {
+               if (!arch_init_data[i].detect())
+                       continue;
+
+               pr_info("Found '%s' privacy-screen provider\n",
+                       arch_init_data[i].lookup.provider);
+
+               /* Make a copy because arch_init_data is __initconst */
+               arch_lookup = arch_init_data[i].lookup;
+               drm_privacy_screen_lookup_add(&arch_lookup);
+               break;
+       }
+}
+
+void drm_privacy_screen_lookup_exit(void)
+{
+       if (arch_lookup.provider)
+               drm_privacy_screen_lookup_remove(&arch_lookup);
+}
+#endif /* ifdef CONFIG_X86 */

diff --git a/include/drm/drm_privacy_screen_machine.h b/include/drm/drm_privacy_screen_machine.h
index aaa0d38..02e5371 100644 (file)
--- a/include/drm/drm_privacy_screen_machine.h
+++ b/include/drm/drm_privacy_screen_machine.h
@@ -31,11 +31,16 @@ struct drm_privacy_screen_lookup {
 void drm_privacy_screen_lookup_add(struct drm_privacy_screen_lookup *lookup);
 void drm_privacy_screen_lookup_remove(struct drm_privacy_screen_lookup *lookup);
 
+#if IS_ENABLED(CONFIG_DRM_PRIVACY_SCREEN) && IS_ENABLED(CONFIG_X86)
+void drm_privacy_screen_lookup_init(void);
+void drm_privacy_screen_lookup_exit(void);
+#else
 static inline void drm_privacy_screen_lookup_init(void)
 {
 }
 static inline void drm_privacy_screen_lookup_exit(void)
 {
 }
+#endif
 
 #endif