diff --git a/sound/core/ump.c b/sound/core/ump.c index fd6a68a54278..117c7ecc4856 100644 --- a/sound/core/ump.c +++ b/sound/core/ump.c @@ -685,10 +685,17 @@ static void seq_notify_protocol(struct snd_ump_endpoint *ump) */ int snd_ump_switch_protocol(struct snd_ump_endpoint *ump, unsigned int protocol) { + unsigned int type; + protocol &= ump->info.protocol_caps; if (protocol == ump->info.protocol) return 0; + type = protocol & SNDRV_UMP_EP_INFO_PROTO_MIDI_MASK; + if (type != SNDRV_UMP_EP_INFO_PROTO_MIDI1 && + type != SNDRV_UMP_EP_INFO_PROTO_MIDI2) + return 0; + ump->info.protocol = protocol; ump_dbg(ump, "New protocol = %x (caps = %x)\n", protocol, ump->info.protocol_caps);