drm/edid: Add drm_rgb_quant_range_selectable()

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@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: David Airlie <airlied@linux.ie>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 5a3770fbd770d63f2338fee03712917f80891146..a3a3b61059ff4ec956bfefdd09c70db1813be7ab 100644 (file)
--- 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.
@@ -1901,6 +1903,37 @@ 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

diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 00d78b5161c025b51fc131cf2cdb98a6359fe24c..30892dc9376e21c1850de88ecc37d31603aafc8b 100644 (file)
--- 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,