[PATCH v2] drm/amdgpu: Add support for drm_privacy_screen

[Sean Paul]

From: Sean Paul <seanpaul at chromium.org>

This patch adds the necessary hooks to make amdgpu aware of privacy
screens. On devices with privacy screen drivers (such as thinkpad-acpi),
the amdgpu driver will defer probe until it's ready and then sync the sw
and hw state on each commit the connector is involved and enabled.

Changes in v2:
-Tweaked the drm_privacy_screen_get() error check to avoid logging
 errors when privacy screen is absent (Hans)

Signed-off-by: Sean Paul <seanpaul at chromium.org>
Link: https://patchwork.freedesktop.org/patch/477640/ #v1
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c          |  9 +++++++++
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c    |  3 +++
 .../amd/display/amdgpu_dm/amdgpu_dm_mst_types.c  | 16 +++++++++++++++-
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 2ab675123ae3..e2cfae56c020 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -26,6 +26,7 @@
 #include <drm/drm_aperture.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_gem.h>
+#include <drm/drm_privacy_screen_consumer.h>
 #include <drm/drm_vblank.h>
 #include <drm/drm_managed.h>
 #include "amdgpu_drv.h"
@@ -1988,6 +1989,7 @@ static int amdgpu_pci_probe(struct pci_dev *pdev,
 {
 	struct drm_device *ddev;
 	struct amdgpu_device *adev;
+	struct drm_privacy_screen *privacy_screen;
 	unsigned long flags = ent->driver_data;
 	int ret, retry = 0, i;
 	bool supports_atomic = false;
@@ -2063,6 +2065,13 @@ static int amdgpu_pci_probe(struct pci_dev *pdev,
 	size = pci_resource_len(pdev, 0);
 	is_fw_fb = amdgpu_is_fw_framebuffer(base, size);
 
+	/* If the LCD panel has a privacy screen, defer probe until its ready */
+	privacy_screen = drm_privacy_screen_get(&pdev->dev, NULL);
+	if (IS_ERR(privacy_screen) && PTR_ERR(privacy_screen) == -EPROBE_DEFER)
+		return -EPROBE_DEFER;
+
+	drm_privacy_screen_put(privacy_screen);
+
 	/* Get rid of things like offb */
 	ret = drm_aperture_remove_conflicting_pci_framebuffers(pdev, &amdgpu_kms_driver);
 	if (ret)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index e1d3db3fe8de..9e2bb6523add 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -9781,6 +9781,9 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
 		if (acrtc) {
 			new_crtc_state = drm_atomic_get_new_crtc_state(state, &acrtc->base);
 			old_crtc_state = drm_atomic_get_old_crtc_state(state, &acrtc->base);
+
+			/* Sync the privacy screen state between hw and sw */
+			drm_connector_update_privacy_screen(new_con_state);
 		}
 
 		/* Skip any modesets/resets */
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
index 740435ae3997..594a8002975a 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
@@ -27,6 +27,7 @@
 #include <drm/drm_atomic_helper.h>
 #include <drm/dp/drm_dp_mst_helper.h>
 #include <drm/dp/drm_dp_helper.h>
+#include <drm/drm_privacy_screen_consumer.h>
 #include "dm_services.h"
 #include "amdgpu.h"
 #include "amdgpu_dm.h"
@@ -506,6 +507,7 @@ void amdgpu_dm_initialize_dp_connector(struct amdgpu_display_manager *dm,
 				       struct amdgpu_dm_connector *aconnector,
 				       int link_index)
 {
+	struct drm_device *dev = dm->ddev;
 	struct dc_link_settings max_link_enc_cap = {0};
 
 	aconnector->dm_dp_aux.aux.name =
@@ -519,8 +521,20 @@ void amdgpu_dm_initialize_dp_connector(struct amdgpu_display_manager *dm,
 	drm_dp_cec_register_connector(&aconnector->dm_dp_aux.aux,
 				      &aconnector->base);
 
-	if (aconnector->base.connector_type == DRM_MODE_CONNECTOR_eDP)
+	if (aconnector->base.connector_type == DRM_MODE_CONNECTOR_eDP) {
+		struct drm_privacy_screen *privacy_screen;
+
+		/* Reference given up in drm_connector_cleanup() */
+		privacy_screen = drm_privacy_screen_get(dev->dev, NULL);
+		if (!IS_ERR(privacy_screen)) {
+			drm_connector_attach_privacy_screen_provider(&aconnector->base,
+								     privacy_screen);
+		} else if (PTR_ERR(privacy_screen) != -ENODEV) {
+			drm_err(dev, "Error getting privacy screen, ret=%d\n",
+				PTR_ERR(privacy_screen));
+		}
 		return;
+	}
 
 	dc_link_dp_get_max_link_enc_cap(aconnector->dc_link, &max_link_enc_cap);
 	aconnector->mst_mgr.cbs = &dm_mst_cbs;
-- 
Sean Paul, Software Engineer, Google / Chromium OS