drm/edid: parse the DisplayID v2.0 VESA vendor block for MSO

[linux-2.6-microblaze.git] / drivers / gpu / drm / drm_edid.c

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 92974b1..c45c225 100644 (file)
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -28,6 +28,7 @@
  * DEALINGS IN THE SOFTWARE.
  */
 
+#include <linux/bitfield.h>
 #include <linux/hdmi.h>
 #include <linux/i2c.h>
 #include <linux/kernel.h>
@@ -5145,6 +5146,71 @@ void drm_get_monitor_range(struct drm_connector *connector,
                      info->monitor_range.max_vfreq);
 }
 
+static void drm_parse_vesa_mso_data(struct drm_connector *connector,
+                                   const struct displayid_block *block)
+{
+       struct displayid_vesa_vendor_specific_block *vesa =
+               (struct displayid_vesa_vendor_specific_block *)block;
+       struct drm_display_info *info = &connector->display_info;
+
+       if (block->num_bytes < 3) {
+               drm_dbg_kms(connector->dev, "Unexpected vendor block size %u\n",
+                           block->num_bytes);
+               return;
+       }
+
+       if (oui(vesa->oui[0], vesa->oui[1], vesa->oui[2]) != VESA_IEEE_OUI)
+               return;
+
+       if (sizeof(*vesa) != sizeof(*block) + block->num_bytes) {
+               drm_dbg_kms(connector->dev, "Unexpected VESA vendor block size\n");
+               return;
+       }
+
+       switch (FIELD_GET(DISPLAYID_VESA_MSO_MODE, vesa->mso)) {
+       default:
+               drm_dbg_kms(connector->dev, "Reserved MSO mode value\n");
+               fallthrough;
+       case 0:
+               info->mso_stream_count = 0;
+               break;
+       case 1:
+               info->mso_stream_count = 2; /* 2 or 4 links */
+               break;
+       case 2:
+               info->mso_stream_count = 4; /* 4 links */
+               break;
+       }
+
+       if (!info->mso_stream_count) {
+               info->mso_pixel_overlap = 0;
+               return;
+       }
+
+       info->mso_pixel_overlap = FIELD_GET(DISPLAYID_VESA_MSO_OVERLAP, vesa->mso);
+       if (info->mso_pixel_overlap > 8) {
+               drm_dbg_kms(connector->dev, "Reserved MSO pixel overlap value %u\n",
+                           info->mso_pixel_overlap);
+               info->mso_pixel_overlap = 8;
+       }
+
+       drm_dbg_kms(connector->dev, "MSO stream count %u, pixel overlap %u\n",
+                   info->mso_stream_count, info->mso_pixel_overlap);
+}
+
+static void drm_update_mso(struct drm_connector *connector, const struct edid *edid)
+{
+       const struct displayid_block *block;
+       struct displayid_iter iter;
+
+       displayid_iter_edid_begin(edid, &iter);
+       displayid_iter_for_each(block, &iter) {
+               if (block->tag == DATA_BLOCK_2_VENDOR_SPECIFIC)
+                       drm_parse_vesa_mso_data(connector, block);
+       }
+       displayid_iter_end(&iter);
+}
+
 /* A connector has no EDID information, so we've got no EDID to compute quirks from. Reset
  * all of the values which would have been set from EDID
  */
@@ -5168,6 +5234,9 @@ drm_reset_display_info(struct drm_connector *connector)
 
        info->non_desktop = 0;
        memset(&info->monitor_range, 0, sizeof(info->monitor_range));
+
+       info->mso_stream_count = 0;
+       info->mso_pixel_overlap = 0;
 }
 
 u32 drm_add_display_info(struct drm_connector *connector, const struct edid *edid)
@@ -5246,6 +5315,9 @@ u32 drm_add_display_info(struct drm_connector *connector, const struct edid *edi
                info->color_formats |= DRM_COLOR_FORMAT_YCRCB444;
        if (edid->features & DRM_EDID_FEATURE_RGB_YCRCB422)
                info->color_formats |= DRM_COLOR_FORMAT_YCRCB422;
+
+       drm_update_mso(connector, edid);
+
        return quirks;
 }