KWIN_PIVOT: campaign closed end-to-end (part 3 update)

Three patches landed on ohm in sequence today: qt6-base-fourier
(GL_ALPHA → GL_R8 on ES 3.x, 3 sites in qtbase), kwin-fourier
(watchDmaBuf no-op test fixture), chromium-fourier patch 4/4
(V4L2 capture pool floor at 16). Each unsticks one layer.

Together they produce smooth 1080p30 H.264 playback under KDE
Plasma 6.6.4 Wayland on RK3566 PineTab2 mainline, where stock
chromium previously stalled in 3 seconds. Combined chrome CPU
~81% steady, KWin ~9%, zero GL_INVALID_VALUE during playback.

Brave's YouTube on the same compositor session also feels snappier
independently — the kwin-fourier watchDmaBuf bypass is a
general-purpose latency reduction for every wp_linux_dmabuf client
on Mali-class hardware, not chrome-specific.

The kernel-side architectural hole is the right upstream-correct
fix: vb2 / hantro / rga don't populate dma_resv exclusive fences
for V4L2 producers, so dma_buf_export_sync_file substitutes a stub
fence representing nothing real. Per-driver fence wiring (3 small
commits: vb2 helper API, hantro opt-in, rga opt-in) plus a parallel
KWin commit using poll(POLLIN) directly on the dmabuf fd is the
planned MR pair. kwin-fourier as it stands is a working diagnostic,
not the upstream-bound shape.

arch/qt6-base-fourier/PKGBUILD

@@ -110,11 +110,11 @@ optdepends=('freetds: MS SQL driver'
 groups=(qt6)
 _pkgfn=${pkgbase/6-/}
 source=(git+https://code.qt.io/qt/$_pkgfn#tag=v$_pkgver
-        patches/qt6-base-cflags.patch
-        patches/qt6-base-nostrip.patch
-        patches/0001-qopengltextureglyphcache-pick-GL_R8-on-ES3.patch
-        patches/0002-qrhigles2-RED_OR_ALPHA8-pick-GL_R8-on-ES3.patch
-        patches/0003-qopengltextureuploader-pick-GL_R8-on-ES3.patch)
+        qt6-base-cflags.patch
+        qt6-base-nostrip.patch
+        0001-qopengltextureglyphcache-pick-GL_R8-on-ES3.patch
+        0002-qrhigles2-RED_OR_ALPHA8-pick-GL_R8-on-ES3.patch
+        0003-qopengltextureuploader-pick-GL_R8-on-ES3.patch)
 sha256sums=('2223c075e95d86f8dbf6395b025a74d996c418f094453c903290e3c2663fbed2'
             '5411edbe215c24b30448fac69bd0ba7c882f545e8cf05027b2b6e2227abc5e78'
             '4b93f6a79039e676a56f9d6990a324a64a36f143916065973ded89adc621e094'
@@ -123,20 +123,20 @@ sha256sums=('2223c075e95d86f8dbf6395b025a74d996c418f094453c903290e3c2663fbed2'
             'SKIP')
 
 prepare() {
-  patch -d $_pkgfn -p1 < patches/qt6-base-cflags.patch # Use system CFLAGS
-  patch -d $_pkgfn -p1 < patches/qt6-base-nostrip.patch # Don't strip binaries with qmake
+  patch -d $_pkgfn -p1 < qt6-base-cflags.patch # Use system CFLAGS
+  patch -d $_pkgfn -p1 < qt6-base-nostrip.patch # Don't strip binaries with qmake
 
   # cherry-pick needs git author identity; git-cli refuses without it.
   git -C $_pkgfn -c user.email=fourier@build -c user.name='qt6-base-fourier build' \
       cherry-pick -n 8b54513cdcf62047376a5d27d784ad68a8f235bf # Fix qdbus crashes
 
   # qt6-base-fourier — three small runtime-checks that pick GL_R8 over
-  # GL_ALPHA when the live GL context is ES 3 or newer. See patches/
-  # for the per-site diagnosis. The chromium-fourier KWIN_PIVOT.md
-  # writeup carries the discovery thread.
-  patch -d $_pkgfn -p1 < patches/0001-qopengltextureglyphcache-pick-GL_R8-on-ES3.patch
-  patch -d $_pkgfn -p1 < patches/0002-qrhigles2-RED_OR_ALPHA8-pick-GL_R8-on-ES3.patch
-  patch -d $_pkgfn -p1 < patches/0003-qopengltextureuploader-pick-GL_R8-on-ES3.patch
+  # GL_ALPHA when the live GL context is ES 3 or newer. See the
+  # individual patch headers for per-site diagnosis. The
+  # chromium-fourier KWIN_PIVOT.md writeup carries the discovery thread.
+  patch -d $_pkgfn -p1 < 0001-qopengltextureglyphcache-pick-GL_R8-on-ES3.patch
+  patch -d $_pkgfn -p1 < 0002-qrhigles2-RED_OR_ALPHA8-pick-GL_R8-on-ES3.patch
+  patch -d $_pkgfn -p1 < 0003-qopengltextureuploader-pick-GL_R8-on-ES3.patch
 }
 
 build() {
@@ -165,6 +165,7 @@ build() {
     -DFEATURE_system_sqlite=ON \
     -DFEATURE_system_xcb_xinput=ON \
     -DFEATURE_no_direct_extern_access=$_no_direct_extern_access \
+    -DFEATURE_sql_ibase=OFF \
     -DCMAKE_INTERPROCEDURAL_OPTIMIZATION=ON \
     -DCMAKE_MESSAGE_LOG_LEVEL=STATUS
   cmake --build build