diff --git a/src/mesa/state_tracker/st_cb_drawpixels.c b/src/mesa/state_tracker/st_cb_drawpixels.c
index 9f1b427a940..8e2714db0cf 100644
--- a/src/mesa/state_tracker/st_cb_drawpixels.c
+++ b/src/mesa/state_tracker/st_cb_drawpixels.c
@@ -398,6 +398,8 @@ internal_format(struct gl_context *ctx, GLenum format, GLenum type)
 
          case GL_UNSIGNED_BYTE_3_3_2:
          case GL_UNSIGNED_BYTE_2_3_3_REV:
+            return GL_R3_G3_B2;
+
          case GL_UNSIGNED_SHORT_4_4_4_4:
          case GL_UNSIGNED_SHORT_4_4_4_4_REV:
             return GL_RGBA4;