fresnel-fourier iter4 Phase 6 commit A: VP9 enumeration + dispatch in config.c

3 sites:
1. RequestQueryConfigProfiles: probe V4L2_PIX_FMT_VP9_FRAME against
   single + MPLANE OUTPUT formats; advertise VAProfileVP9Profile0.
2. RequestCreateConfig: VAProfileVP9Profile0 case (no profile-specific
   validation; defer to vaCreateContext / control submission time).
3. RequestQueryConfigEntrypoints: add VAProfileVP9Profile0 to the
   VAEntrypointVLD fall-through.

Verified on fresnel: vainfo (auto-detect rkvdec) now shows
VAProfileVP9Profile0 alongside H.264x5 + HEVCMain.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/config.c

@@ -79,6 +79,10 @@ VAStatus RequestCreateConfig(VADriverContextP context, VAProfile profile,
 		// backend; validation happens at vaCreateContext / control
 		// submission time.
 		break;
+	case VAProfileVP9Profile0:
+		// fresnel-fourier iter4: VP9 Profile 0 enabled on rkvdec.
+		// Same shape — no profile-specific validation here.
+		break;
 	default:
 		return VA_STATUS_ERROR_UNSUPPORTED_PROFILE;
 	}
@@ -175,6 +179,16 @@ VAStatus RequestQueryConfigProfiles(VADriverContextP context,
 	if (found && index < (V4L2_REQUEST_MAX_CONFIG_ATTRIBUTES - 1))
 		profiles[index++] = VAProfileVP8Version0_3;
 
+	/* fresnel-fourier iter4: VP9 enumeration on rkvdec */
+	found = v4l2_find_format(driver_data->video_fd,
+				 V4L2_BUF_TYPE_VIDEO_OUTPUT,
+				 V4L2_PIX_FMT_VP9_FRAME) ||
+		v4l2_find_format(driver_data->video_fd,
+				 V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE,
+				 V4L2_PIX_FMT_VP9_FRAME);
+	if (found && index < (V4L2_REQUEST_MAX_CONFIG_ATTRIBUTES - 1))
+		profiles[index++] = VAProfileVP9Profile0;
+
 	*profiles_count = index;
 
 	return VA_STATUS_SUCCESS;
@@ -195,6 +209,7 @@ VAStatus RequestQueryConfigEntrypoints(VADriverContextP context,
 	case VAProfileH264StereoHigh:
 	case VAProfileHEVCMain:
 	case VAProfileVP8Version0_3:
+	case VAProfileVP9Profile0:
 		entrypoints[0] = VAEntrypointVLD;
 		*entrypoints_count = 1;
 		break;