[Intel-gfx] [PATCH 9/9] drm/i915: Add privacy-screen support

[Hans de Goede]

Add support for eDP panels with a built-in privacy screen using the
new drm_privacy_screen class.

One thing which stands out here is the addition of these 2 lines to
intel_atomic_commit_tail:

	for_each_new_connector_in_state(&state->base, connector, ...
		drm_connector_update_privacy_screen(connector, state);

It may seem more logical to instead take care of updating the
privacy-screen state by marking the crtc as needing a modeset and then
do this in both the encoder update_pipe (for fast-sets) and enable
(for full modesets) callbacks. But ATM these callbacks only get passed
the new connector_state and these callbacks are all called after
drm_atomic_helper_swap_state() at which point there is no way to get
the old state from the new state.

Without access to the old state, we do not know if the sw_state of
the privacy-screen has changes so we would need to call
drm_privacy_screen_set_sw_state() unconditionally. This is undesirable
since all current known privacy-screen providers use ACPI calls which
are somewhat expensive to make.

Also, as all providers use ACPI calls, rather then poking GPU registers,
there is no need to order this together with other encoder operations.
Since no GPU poking is involved having this as a separate step of the
commit process actually is the logical thing to do.

Reviewed-by: Emil Velikov <emil.l.velikov at gmail.com>
Signed-off-by: Hans de Goede <hdegoede at redhat.com>
---
 drivers/gpu/drm/i915/display/intel_display.c |  5 +++++
 drivers/gpu/drm/i915/display/intel_dp.c      | 10 ++++++++++
 drivers/gpu/drm/i915/i915_pci.c              | 12 ++++++++++++
 3 files changed, 27 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 5560d2f4c352..7285873d329a 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -10140,6 +10140,8 @@ static void intel_atomic_commit_tail(struct intel_atomic_state *state)
 	struct drm_device *dev = state->base.dev;
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	struct intel_crtc_state *new_crtc_state, *old_crtc_state;
+	struct drm_connector_state *new_connector_state;
+	struct drm_connector *connector;
 	struct intel_crtc *crtc;
 	u64 put_domains[I915_MAX_PIPES] = {};
 	intel_wakeref_t wakeref = 0;
@@ -10237,6 +10239,9 @@ static void intel_atomic_commit_tail(struct intel_atomic_state *state)
 			intel_color_load_luts(new_crtc_state);
 	}
 
+	for_each_new_connector_in_state(&state->base, connector, new_connector_state, i)
+		drm_connector_update_privacy_screen(connector, &state->base);
+
 	/*
 	 * Now that the vblank has passed, we can go ahead and program the
 	 * optimal watermarks on platforms that need two-step watermark
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 7f8e8865048f..3aa2072cccf6 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -37,6 +37,7 @@
 #include <drm/drm_crtc.h>
 #include <drm/drm_dp_helper.h>
 #include <drm/drm_edid.h>
+#include <drm/drm_privacy_screen_consumer.h>
 #include <drm/drm_probe_helper.h>
 
 #include "g4x_dp.h"
@@ -5217,6 +5218,7 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
 	struct drm_connector *connector = &intel_connector->base;
 	struct drm_display_mode *fixed_mode = NULL;
 	struct drm_display_mode *downclock_mode = NULL;
+	struct drm_privacy_screen *privacy_screen;
 	bool has_dpcd;
 	enum pipe pipe = INVALID_PIPE;
 	struct edid *edid;
@@ -5308,6 +5310,14 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
 				fixed_mode->hdisplay, fixed_mode->vdisplay);
 	}
 
+	privacy_screen = drm_privacy_screen_get(dev->dev, NULL);
+	if (!IS_ERR(privacy_screen)) {
+		drm_connector_attach_privacy_screen_provider(connector,
+							     privacy_screen);
+	} else if (PTR_ERR(privacy_screen) != -ENODEV) {
+		drm_warn(&dev_priv->drm, "Error getting privacy-screen\n");
+	}
+
 	return true;
 
 out_vdd_off:
diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c
index 146f7e39182a..d6913f567a1c 100644
--- a/drivers/gpu/drm/i915/i915_pci.c
+++ b/drivers/gpu/drm/i915/i915_pci.c
@@ -25,6 +25,7 @@
 #include <linux/vga_switcheroo.h>
 
 #include <drm/drm_drv.h>
+#include <drm/drm_privacy_screen_consumer.h>
 #include <drm/i915_pciids.h>
 
 #include "i915_drv.h"
@@ -1167,6 +1168,7 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 {
 	struct intel_device_info *intel_info =
 		(struct intel_device_info *) ent->driver_data;
+	struct drm_privacy_screen *privacy_screen;
 	int err;
 
 	if (intel_info->require_force_probe &&
@@ -1195,7 +1197,17 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (vga_switcheroo_client_probe_defer(pdev))
 		return -EPROBE_DEFER;
 
+	/*
+	 * We do not handle -EPROBE_DEFER further into the probe process, so
+	 * check if we have a laptop-panel privacy-screen for which the driver
+	 * has not loaded yet here.
+	 */
+	privacy_screen = drm_privacy_screen_get(&pdev->dev, NULL);
+	if (IS_ERR(privacy_screen) && PTR_ERR(privacy_screen) == -EPROBE_DEFER)
+		return -EPROBE_DEFER;
+
 	err = i915_driver_probe(pdev, ent);
+	drm_privacy_screen_put(privacy_screen);
 	if (err)
 		return err;
 
-- 
2.31.1