From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
drm_rgb_quant_range_selectable() will report whether the monitor
claims to support for RGB quantization range selection.
The information can be found in the CEA Video capability block.
v2: s/quantzation/quantization/ in the comment
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx>
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/drm_edid.c | 33 +++++++++++++++++++++++++++++++++
include/drm/drm_crtc.h | 1 +
2 files changed, 34 insertions(+), 0 deletions(-)
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 5a3770f..a3a3b61 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -1483,9 +1483,11 @@ add_detailed_modes(struct drm_connector *connector, struct edid *edid,
#define VIDEO_BLOCK 0x02
#define VENDOR_BLOCK 0x03
#define SPEAKER_BLOCK 0x04
+#define VIDEO_CAPABILITY_BLOCK 0x07
#define EDID_BASIC_AUDIO (1 << 6)
#define EDID_CEA_YCRCB444 (1 << 5)
#define EDID_CEA_YCRCB422 (1 << 4)
+#define EDID_CEA_VCDB_QS (1 << 6)
/**
* Search EDID for CEA extension block.
@@ -1902,6 +1904,37 @@ end:
EXPORT_SYMBOL(drm_detect_monitor_audio);
/**
+ * drm_rgb_quant_range_selectable - is RGB quantization range selectable?
+ *
+ * Check whether the monitor reports the RGB quantization range selection
+ * as supported. The AVI infoframe can then be used to inform the monitor
+ * which quantization range (full or limited) is used.
+ */
+bool drm_rgb_quant_range_selectable(struct edid *edid)
+{
+ u8 *edid_ext;
+ int i, start, end;
+
+ edid_ext = drm_find_cea_extension(edid);
+ if (!edid_ext)
+ return false;
+
+ if (cea_db_offsets(edid_ext, &start, &end))
+ return false;
+
+ for_each_cea_db(edid_ext, i, start, end) {
+ if (cea_db_tag(&edid_ext[i]) == VIDEO_CAPABILITY_BLOCK &&
+ cea_db_payload_len(&edid_ext[i]) == 2) {
+ DRM_DEBUG_KMS("CEA VCDB 0x%02x\n", edid_ext[i + 2]);
+ return edid_ext[i + 2] & EDID_CEA_VCDB_QS;
+ }
+ }
+
+ return false;
+}
+EXPORT_SYMBOL(drm_rgb_quant_range_selectable);
+
+/**
* drm_add_display_info - pull display info out if present
* @edid: EDID data
* @info: display info (attached to connector)
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 00d78b5..30892dc 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -1033,6 +1033,7 @@ extern u8 *drm_find_cea_extension(struct edid *edid);
extern u8 drm_match_cea_mode(struct drm_display_mode *to_match);
extern bool drm_detect_hdmi_monitor(struct edid *edid);
extern bool drm_detect_monitor_audio(struct edid *edid);
+extern bool drm_rgb_quant_range_selectable(struct edid *edid);
extern int drm_mode_page_flip_ioctl(struct drm_device *dev,
void *data, struct drm_file *file_priv);
extern struct drm_display_mode *drm_cvt_mode(struct drm_device *dev,
--
1.7.8.6
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