From: Markus Fritsche <mfritsche@reauktion.de>
Subject: [PATCH 4/4] modules/libpref: add media.ffmpeg.v4l2-request.enabled
Date: 2026-04-27

Background
----------
Toggle for the V4L2 stateless (request API) decode path introduced
in patch 3/4. Defaults on for Linux, mirroring the
`media.ffmpeg.vaapi.enabled`-style shape. Users can flip to false to
force the existing stateful `InitV4L2Decoder` (or VAAPI / software
fallbacks) without rebuilding.

Bug 1969297.

diff --git a/modules/libpref/init/StaticPrefList.yaml b/modules/libpref/init/StaticPrefList.yaml
--- a/modules/libpref/init/StaticPrefList.yaml
+++ b/modules/libpref/init/StaticPrefList.yaml
@@ -12159,6 +12159,16 @@
   type: uint32_t
   value: 2
   mirror: once
+
+# firefox-fourier: route V4L2 stateless (request API) decode through
+# libavcodec's v4l2_request hwaccel (AV_HWDEVICE_TYPE_DRM). Required
+# for mainline-Linux Rockchip rkvdec / hantro / rkvdec2. On stateful
+# boards (Pi4 / vendor MPP) the codec's hw_configs lacks a DRM entry
+# and the path silently falls back to InitV4L2Decoder.
+- name: media.ffmpeg.v4l2-request.enabled
+  type: RelaxedAtomicBool
+  value: true
+  mirror: always
 #endif # MOZ_WIDGET_GTK

 # Set to true in marionette tests to disable the sanity test