From 45ae99aff79068d8b975b02c2426d78b19327cd4 Mon Sep 17 00:00:00 2001
From: Pekka Paalanen <pekka.paalanen@collabora.com>
Date: Tue, 5 Sep 2023 17:18:12 +0300
Subject: [PATCH] backend-drm: get KMS colorimetry modes

Based on KMS "Colorspace" connector property, populate the mask of
supported colorimetry modes on a head.

EDID should be checked too, but it is currently ignored.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
---
 libweston/backend-drm/drm.c   |  8 +++++++
 libweston/backend-drm/modes.c | 39 +++++++++++++++++++++++++++++++++++
 libweston/color.c             | 16 ++++++++++++++
 libweston/color.h             |  3 +++
 4 files changed, 66 insertions(+)

diff --git a/libweston/backend-drm/drm.c b/libweston/backend-drm/drm.c
index a5af37d9..f8be3734 100644
--- a/libweston/backend-drm/drm.c
+++ b/libweston/backend-drm/drm.c
@@ -2576,6 +2576,14 @@ drm_head_log_info(struct drm_head *head, const char *msg)
 					    str);
 		}
 		free(str);
+
+		str = weston_colorimetry_mask_to_str(head->base.supported_colorimetry_mask);
+		if (str) {
+			weston_log_continue(STAMP_SPACE
+					    "Supported colorimetry modes: %s\n",
+					    str);
+		}
+		free(str);
 	} else {
 		weston_log("DRM: head '%s' %s, connector %d is disconnected.\n",
 			   head->base.name, msg, head->connector.connector_id);
diff --git a/libweston/backend-drm/modes.c b/libweston/backend-drm/modes.c
index e77fbe6c..79513c8a 100644
--- a/libweston/backend-drm/modes.c
+++ b/libweston/backend-drm/modes.c
@@ -49,6 +49,11 @@ struct drm_head_info {
  	 * enum weston_eotf_mode bits.
 	 */
 	uint32_t eotf_mask;
+
+	/* The monitor supported colorimetry modes, combination of
+	 * enum weston_colorimetry_mode bits.
+	 */
+	uint32_t colorimetry_mask;
 };
 
 static void
@@ -251,6 +256,7 @@ drm_head_info_from_edid(struct drm_head_info *dhi,
 
 	/* TODO: parse this from EDID */
 	dhi->eotf_mask = WESTON_EOTF_MODE_ALL_MASK;
+	dhi->colorimetry_mask = WESTON_COLORIMETRY_MODE_ALL_MASK;
 }
 
 #else /* HAVE_LIBDISPLAY_INFO */
@@ -380,6 +386,7 @@ drm_head_info_from_edid(struct drm_head_info *dhi,
 
 	/* This ad hoc code will never parse HDR data. */
 	dhi->eotf_mask = WESTON_EOTF_MODE_SDR;
+	dhi->colorimetry_mask = WESTON_COLORIMETRY_MODE_DEFAULT;
 }
 
 #endif /* HAVE_LIBDISPLAY_INFO else */
@@ -447,6 +454,35 @@ prune_eotf_modes_by_kms_support(struct drm_head *head, uint32_t *eotf_mask)
 		*eotf_mask = WESTON_EOTF_MODE_SDR;
 }
 
+static uint32_t
+drm_head_get_kms_colorimetry_modes(const struct drm_head *head)
+{
+	const struct drm_property_info *info;
+
+	/* Cannot bother implementing without atomic */
+	if (!head->connector.device->atomic_modeset)
+		return WESTON_COLORIMETRY_MODE_DEFAULT;
+
+	info = &head->connector.props[WDRM_CONNECTOR_COLORSPACE];
+	if (info->prop_id == 0)
+		return WESTON_COLORIMETRY_MODE_DEFAULT;
+
+	uint32_t colorimetry_modes = WESTON_COLORIMETRY_MODE_NONE;
+	unsigned i; /* actually enum wdrm_colorspace */
+
+	for (i = 0; i < WDRM_COLORSPACE__COUNT; i++) {
+		if (info->enum_values[i].valid) {
+			const struct weston_colorimetry_mode_info *cm;
+
+			cm = weston_colorimetry_mode_info_get_by_wdrm(i);
+			if (cm)
+				colorimetry_modes |= cm->mode;
+		}
+	}
+
+	return colorimetry_modes;
+}
+
 static uint32_t
 drm_refresh_rate_mHz(const drmModeModeInfo *info)
 {
@@ -643,6 +679,9 @@ update_head_from_connector(struct drm_head *head)
 	prune_eotf_modes_by_kms_support(head, &dhi.eotf_mask);
 	weston_head_set_supported_eotf_mask(&head->base, dhi.eotf_mask);
 
+	dhi.colorimetry_mask &= drm_head_get_kms_colorimetry_modes(head);
+	weston_head_set_supported_colorimetry_mask(&head->base, dhi.colorimetry_mask);
+
 	drm_head_info_fini(&dhi);
 }
 
diff --git a/libweston/color.c b/libweston/color.c
index 9b9f60a3..4e33946d 100644
--- a/libweston/color.c
+++ b/libweston/color.c
@@ -477,6 +477,22 @@ weston_colorimetry_mode_info_get(enum weston_colorimetry_mode c)
 	return NULL;
 }
 
+/** Get information structure of colorimetry mode from KMS "Colorspace" enum
+ *
+ * \internal
+ */
+WL_EXPORT const struct weston_colorimetry_mode_info *
+weston_colorimetry_mode_info_get_by_wdrm(enum wdrm_colorspace cs)
+{
+	unsigned i;
+
+	for (i = 0; i < ARRAY_LENGTH(colorimetry_mode_info_map); i++)
+		if (colorimetry_mode_info_map[i].wdrm == cs)
+			return &colorimetry_mode_info_map[i];
+
+	return NULL;
+}
+
 /** Get a string naming the colorimetry mode
  *
  * \internal
diff --git a/libweston/color.h b/libweston/color.h
index fff7bd32..8269b12d 100644
--- a/libweston/color.h
+++ b/libweston/color.h
@@ -564,6 +564,9 @@ struct weston_colorimetry_mode_info {
 const struct weston_colorimetry_mode_info *
 weston_colorimetry_mode_info_get(enum weston_colorimetry_mode c);
 
+const struct weston_colorimetry_mode_info *
+weston_colorimetry_mode_info_get_by_wdrm(enum wdrm_colorspace cs);
+
 const char *
 weston_colorimetry_mode_to_str(enum weston_colorimetry_mode c);