firefox-fourier 0003: V4L2REQUEST type acceptance (proper patch, regenerated from real source)

Closes #60.

Resolves the malformed-patch issue from #61 (since reverted in #62)
by regenerating the 0003 patch via actual application against firefox
150.0.3 Pi-OS source.

Functional change vs prior 0003: walking hw_configs accepts
AV_HWDEVICE_TYPE_DRM (legacy) OR integer device_type values 13/14
(AV_HWDEVICE_TYPE_V4L2REQUEST in Kwibos no-AMF / upstream-AMF trees).
CreateV4L2RequestDeviceContext passes integer 13 (Kwibos value) cast
to enum AVHWDeviceType for the av_hwdevice_ctx_create call.

Tested: applied cleanly via patch -p1 against firefox-150.0.3 source
post-Pi-OS-quilt-patches. Test build follow-up in firefox-rpios EC2
script (drops the in-source sed hack from v7-v8).

arch/firefox-fourier/0003-ffmpegvideo-v4l2-request-route.patch

@@ -18,27 +18,30 @@ This patch adds a sibling init path, `InitV4L2RequestDecoder`, that:
   * looks up the codec via two complementary mechanisms libavcodec
     uses for v4l2_request:
       - **named codec** (`h264_v4l2request`, `vp8_v4l2request`, etc.):
-        the legacy AVCodec-per-hwaccel registration. ALARM, Debian,
+        the legacy AVCodec-per-hwaccel registration.
-        and most distros building with --enable-v4l2-request expose
+      - **generic codec + hw_configs walk**: the modern hwaccel
-        this (avcodec_find_decoder_by_name lookup).
+        registration. Accepts EITHER AV_HWDEVICE_TYPE_DRM (legacy
-      - **generic codec + AV_HWDEVICE_TYPE_DRM** in `hw_configs`:
+        ffmpeg-v4l2-request-fork output prior to FFmpeg 7.1) OR
-        the modern hwaccel registration on some upstream-only ffmpeg
+        AV_HWDEVICE_TYPE_V4L2REQUEST (FFmpeg 7.1+ dedicated enum,
-        builds.
+        value 13 on Kwiboo's no-AMF tree, 14 on upstream-AMF tree).
+        Mozilla's bundled libavutil headers may not have the V4L2REQUEST
+        enumerator, so the test is on the integer value via `(int)cast`.
     Probes named-codec first (explicit, portable) and falls back to
-    walking the generic codec's `hw_configs` for the DRM device type;
+    walking the generic codec's `hw_configs` for either device type;
-  * creates an `AV_HWDEVICE_TYPE_DRM` hwdevice context bound to
+  * creates an hwdevice context bound to `/dev/dri/renderD128`. Uses
-    `/dev/dri/renderD128` via the new `av_hwdevice_ctx_create` wrapper
+    integer 13 (V4L2REQUEST as defined by Kwiboo's v4l2-request-n7.1.3
-    (patch 2/4) and attaches it to the codec context;
+    tree, what our libavcodec61-fourier emits) cast to enum
+    AVHWDeviceType for the av_hwdevice_ctx_create call;
   * reuses the existing `ChooseV4L2PixelFormat` get-format callback
     (already returns `AV_PIX_FMT_DRM_PRIME`) and the existing
     `apply_cropping = 0` constraint.
 
 `InitV4L2RequestDecoder` is invoked **before** `InitV4L2Decoder` in
 `InitHWDecoderIfAllowed`. On Rockchip mainline it succeeds via either
-mechanism (ALARM uses the named codec). On Pi4 / Mediatek /
+mechanism. On Pi4 / Mediatek / vendor-MPP-stateful boards neither
-vendor-MPP-stateful boards neither mechanism is registered for the
+mechanism is registered for the codec, the function bails out, and the
-codec, the function bails out, and the existing stateful
+existing stateful `InitV4L2Decoder` runs as before. No regression of
-`InitV4L2Decoder` runs as before. No regression of stateful boards.
+stateful boards.
 
 `mDRMDeviceContext` is unconditionally `av_buffer_unref`'d in
 `ProcessShutdown` (no-op when null). Gated behind
@@ -46,9 +49,8 @@ codec, the function bails out, and the existing stateful
 
 Bug 1969297.
 
-diff --git a/dom/media/platforms/ffmpeg/FFmpegVideoDecoder.h b/dom/media/platforms/ffmpeg/FFmpegVideoDecoder.h
+--- a/dom/media/platforms/ffmpeg/FFmpegVideoDecoder.h	2026-05-21 04:57:59.570946601 +0000
---- a/dom/media/platforms/ffmpeg/FFmpegVideoDecoder.h	2026-03-18 19:22:14.000000000 +0000
++++ b/dom/media/platforms/ffmpeg/FFmpegVideoDecoder.h	2026-05-21 04:57:59.876488776 +0000
-+++ b/dom/media/platforms/ffmpeg/FFmpegVideoDecoder.h	2026-04-27 20:43:39.347992674 +0000
 @@ -225,7 +225,12 @@
    bool IsLinuxHDR() const;
    MediaResult InitVAAPIDecoder();
@@ -73,9 +75,8 @@ diff --git a/dom/media/platforms/ffmpeg/FFmpegVideoDecoder.h b/dom/media/platfor
    // If video overlay is used we want to upload SW decoded frames to
    // DMABuf and present it as a external texture to rendering pipeline.
    bool mUploadSWDecodeToDMABuf = false;
-diff --git a/dom/media/platforms/ffmpeg/FFmpegVideoDecoder.cpp b/dom/media/platforms/ffmpeg/FFmpegVideoDecoder.cpp
+--- a/dom/media/platforms/ffmpeg/FFmpegVideoDecoder.cpp	2026-05-21 04:57:59.566685221 +0000
---- a/dom/media/platforms/ffmpeg/FFmpegVideoDecoder.cpp	2026-04-27 16:09:10.000000000 +0200
++++ b/dom/media/platforms/ffmpeg/FFmpegVideoDecoder.cpp	2026-05-21 04:58:00.136004159 +0000
-+++ b/dom/media/platforms/ffmpeg/FFmpegVideoDecoder.cpp	2026-04-29 00:10:00.098884335 +0200
 @@ -403,6 +403,129 @@
    return NS_OK;
  }
@@ -90,7 +91,7 @@ diff --git a/dom/media/platforms/ffmpeg/FFmpegVideoDecoder.cpp b/dom/media/platf
 +  }
 +  const char* drmDevice = "/dev/dri/renderD128";
 +  if (mLib->av_hwdevice_ctx_create(&mDRMDeviceContext,
-+                                   AV_HWDEVICE_TYPE_DRM, drmDevice,
++                                   (enum AVHWDeviceType)13, drmDevice,
 +                                   nullptr, 0) < 0) {
 +    FFMPEG_LOG("  av_hwdevice_ctx_create(DRM, %s) failed", drmDevice);
 +    return false;
@@ -143,7 +144,7 @@ diff --git a/dom/media/platforms/ffmpeg/FFmpegVideoDecoder.cpp b/dom/media/platf
 +      for (int i = 0;; i++) {
 +        const AVCodecHWConfig* cfg = mLib->avcodec_get_hw_config(generic, i);
 +        if (!cfg) break;
-+        if (cfg->device_type == AV_HWDEVICE_TYPE_DRM) {
++        if (cfg->device_type == AV_HWDEVICE_TYPE_DRM || (int)cfg->device_type == 13 || (int)cfg->device_type == 14) {
 +          codec = generic;
 +          FFMPEG_LOG("  using generic codec %s with DRM hwaccel", codec->name);
 +          break;