From 409f07d353b3516c71fdf12d7fa576004f0167a9 Mon Sep 17 00:00:00 2001
From: Simon Ser <contact@emersion.fr>
Date: Tue, 28 Feb 2023 12:32:04 +0000
Subject: [PATCH] drm: document connector margin properties
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Add docs for "{left,right,top,bottom} margin" properties.
v2:
- Mention the purpose: mitigate underscan on TVs
- Move out of analog TV section into standard props (Pekka)
- Mention HDMI AVI InfoFrames (Pekka, Ville)
Signed-off-by: Simon Ser <contact@emersion.fr>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Noralf Trønnes <noralf@tronnes.org>
Cc: Mateusz Kwiatkowski <kfyatek+publicgit@gmail.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Acked-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230228123156.175973-1-contact@emersion.fr
---
drivers/gpu/drm/drm_connector.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index ca5fb54b7aab9..d031a857e0bed 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -1449,6 +1449,20 @@ static const struct drm_prop_enum_list dp_colorspaces[] = {
* a firmware handled hotkey. Therefor userspace must not include the
* privacy-screen sw-state in an atomic commit unless it wants to change
* its value.
+ *
+ * left margin, right margin, top margin, bottom margin:
+ * Add margins to the connector's viewport. This is typically used to
+ * mitigate underscan on TVs.
+ *
+ * The value is the size in pixels of the black border which will be
+ * added. The attached CRTC's content will be scaled to fill the whole
+ * area inside the margin.
+ *
+ * The margins configuration might be sent to the sink, e.g. via HDMI AVI
+ * InfoFrames.
+ *
+ * Drivers can set up these properties by calling
+ * drm_mode_create_tv_margin_properties().
*/
int drm_connector_create_standard_properties(struct drm_device *dev)
@@ -1593,10 +1607,6 @@ EXPORT_SYMBOL(drm_connector_attach_dp_subconnector_property);
/*
* TODO: Document the properties:
- * - left margin
- * - right margin
- * - top margin
- * - bottom margin
* - brightness
* - contrast
* - flicker reduction
--
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