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Date:   Sun, 10 Nov 2019 21:08:48 +0100
From:   Aurelien Jarno <aurelien@aurel32.net>
To:     linux-bluetooth@vger.kernel.org
Subject: BlueZ/mesh: RX not working after daemon restart (with workaround)
Message-ID: <20191110200848.GA28864@aurel32.net>
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Hi all,

On my system (Raspberry PI 3), the RX path doesn't work anymore
following a restart of the bluetooth-meshd daemon. I have tracked down
that to the fact that the receive callbacks are setup before the HCI is
fully initialized. Said otherwise, BT_HCI_CMD_LE_SET_SCAN_PARAMETERS is
called before BT_HCI_CMD_RESET and the callback calling
BT_HCI_CMD_LE_SET_SCAN_ENABLE is not called. This timing dependent and
probably not reproducible on all hardware.

I have workarounded the issue by adding a small delay between the HCI
initialization and the call to node_attach_io_all():

diff --git a/mesh/mesh.c b/mesh/mesh.c
index 9b2b2073b..1c06060f9 100644
--- a/mesh/mesh.c
+++ b/mesh/mesh.c
@@ -167,6 +167,10 @@ bool mesh_init(const char *config_dir, enum mesh_io_type type, void *opts)
 	mesh_io_get_caps(mesh.io, &caps);
 	mesh.max_filters = caps.max_num_filters;
 
+	for (int i = 0 ; i < 100 ; i++) {
+		l_main_iterate(10);
+	}
+
 	node_attach_io_all(mesh.io);
 
 	return true;

I guess there is a better way to do that by waiting for the HCI to be
fully initialized before calling node_attach_io_all() or by using a
callback instead. However I do not know the codebase good enough to fix
that properly.

Aurelien

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien@aurel32.net                 http://www.aurel32.net