[pulseaudio-discuss] [PATCH] bluez: Don't autodetect MTU by default

[Georg Chini]

On 13.09.2017 05:54, Arun Raghavan wrote:
> This breaks a lot of headsets, so disabling by default. Can be
> re-enabled in configuration for specific hardware where it is deemed
> necessary.
>
> Also added some debug logging to be able to examine what MTU size is
> reported by the device.
>
> BugLink: https://bugs.freedesktop.org/show_bug.cgi?id=102660
> ---
>   src/modules/bluetooth/backend-native.c         | 1 +
>   src/modules/bluetooth/module-bluez5-device.c   | 2 +-
>   src/modules/bluetooth/module-bluez5-discover.c | 2 +-
>   3 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/src/modules/bluetooth/backend-native.c b/src/modules/bluetooth/backend-native.c
> index 6eb4e1682..0f0104d89 100644
> --- a/src/modules/bluetooth/backend-native.c
> +++ b/src/modules/bluetooth/backend-native.c
> @@ -206,6 +206,7 @@ static int sco_acquire_cb(pa_bluetooth_transport *t, bool optional, size_t *imtu
>           if (getsockopt(sock, SOL_SCO, SCO_OPTIONS, &sco_opt, &len) < 0)
>               pa_log_warn("getsockopt(SCO_OPTIONS) failed, loading defaults");
>           else {
> +            pa_log_debug("autodetected imtu = omtu = %u", sco_opt.mtu);
>               if (imtu) *imtu = sco_opt.mtu;
>               if (omtu) *omtu = sco_opt.mtu;
>           }
> diff --git a/src/modules/bluetooth/module-bluez5-device.c b/src/modules/bluetooth/module-bluez5-device.c
> index c0e681b17..a37c3d54f 100644
> --- a/src/modules/bluetooth/module-bluez5-device.c
> +++ b/src/modules/bluetooth/module-bluez5-device.c
> @@ -2256,7 +2256,7 @@ int pa__init(pa_module* m) {
>           goto fail_free_modargs;
>       }
>   
> -    autodetect_mtu = true;
> +    autodetect_mtu = false;
>       if (pa_modargs_get_value_boolean(ma, "autodetect_mtu", &autodetect_mtu) < 0) {
>           pa_log("Invalid boolean value for autodetect_mtu parameter");
>           goto fail_free_modargs;
> diff --git a/src/modules/bluetooth/module-bluez5-discover.c b/src/modules/bluetooth/module-bluez5-discover.c
> index 97ff94357..c535ead41 100644
> --- a/src/modules/bluetooth/module-bluez5-discover.c
> +++ b/src/modules/bluetooth/module-bluez5-discover.c
> @@ -124,7 +124,7 @@ int pa__init(pa_module *m) {
>           goto fail;
>       }
>   
> -    autodetect_mtu = true;
> +    autodetect_mtu = false;
>       if (pa_modargs_get_value_boolean(ma, "autodetect_mtu", &autodetect_mtu) < 0) {
>           pa_log("Invalid boolean value for autodetect_mtu parameter");
>           goto fail;

I think the patch should also address the crash that occurs when
the MTU reported by the kernel is odd. I am not sure what to do
in that case: Round down to an even value (which does not seem
to produce sound) or fall back to 48.