wireplumber: fix audio randomly not working at boot timericefish_18.0.3ricefish/18.0.318.0.3ricefish

This issue is caused by a race condition that triggers some links to be
created and then destroyed very fast, but at a certain point where the
managing object (si-standard-link) is not fully configured yet. At that
point, droping the ref count of the si-standard-link doesn't destroy it
and the links remain dangling, causing a loop in the graph that prevents
audio from working properly.

This patch mitigates the issue by forcing si-standard-link to reset to
its initial state, forcing the pipewire links to be destroyed. This does
not, however, prevent the potential leak of the si-standard-link.
A better solution is being worked on for upstreaming.

Bug-AGL: SPEC-5244
Change-Id: I61477c0c021351903239d58fff0217e25e08db02
Signed-off-by: George Kiagiadakis <george.kiagiadakis@collabora.com>
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl/+/30658
ci-image-boot-test: Jenkins Job builder account
Tested-by: Jenkins Job builder account
ci-image-build: Jenkins Job builder account
Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>

2 files changed, 36 insertions, 0 deletions

diff --git a/meta-pipewire/recipes-multimedia/wireplumber/wireplumber/0001-linking-reset-link-when-moving-target.patch b/meta-pipewire/recipes-multimedia/wireplumber/wireplumber/0001-linking-reset-link-when-moving-target.patch
new file mode 100644
index 000000000..690d3de1f
--- /dev/null
+++ b/meta-pipewire/recipes-multimedia/wireplumber/wireplumber/0001-linking-reset-link-when-moving-target.patch
@@ -0,0 +1,30 @@
+From 658e9bbe4daee17844cd5b5bf5014bca9ec76ba4 Mon Sep 17 00:00:00 2001
+From: George Kiagiadakis <george.kiagiadakis@collabora.com>
+Date: Fri, 13 Dec 2024 11:58:24 +0200
+Subject: [PATCH] linking: reset link when moving target
+
+This ensures that the real pipewire links will be
+destroyed, since the link may not be fully activated yet.
+This fix is not entirely correct, because it will likely
+leak the si-standard-link, but it will get audio working.
+
+Upstream-Status: Inappropriate [not entirely correct]
+---
+ src/scripts/linking/prepare-link.lua | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/src/scripts/linking/prepare-link.lua b/src/scripts/linking/prepare-link.lua
+index 69da939c..38fee98f 100644
+--- a/src/scripts/linking/prepare-link.lua
++++ b/src/scripts/linking/prepare-link.lua
+@@ -57,6 +57,7 @@ SimpleEventHook {
+             log:warning (link, "Link was not activated before removing")
+           end
+           si_flags.peer_id = nil
++          link:reset ()
+           link:remove ()
+           log:info (si, "... moving to new target")
+         end
+-- 
+2.45.2
+
diff --git a/meta-pipewire/recipes-multimedia/wireplumber/wireplumber_%.bbappend b/meta-pipewire/recipes-multimedia/wireplumber/wireplumber_%.bbappend
index 16d3817cd..bf71dc3c3 100644
--- a/meta-pipewire/recipes-multimedia/wireplumber/wireplumber_%.bbappend
+++ b/meta-pipewire/recipes-multimedia/wireplumber/wireplumber_%.bbappend
@@ -1,3 +1,9 @@
+FILESEXTRAPATHS:prepend := "${THISDIR}/${PN}:"
+
+SRC_URI += " \
+    file://0001-linking-reset-link-when-moving-target.patch \
+"
+
 do_install:append() {
     systemd_dir="${D}${sysconfdir}/systemd/system/"