From: Takashi Iwai <tiwai@xxxxxxx> [ Upstream commit bc42ca002d5d211f9c57334b9b4c25ddb0b4ec35 ] When an inquiry of the current protocol via UMP Stream Configuration message fails by some reason, we may leave the current protocol undefined, which may lead to unexpected behavior. Better to assume a valid protocol found in the protocol capability bits instead. For a device that doesn't support the UMP v1.2 feature, it won't reach to this code path, and USB MIDI GTB descriptor would be used for determining the protocol, instead. Link: https://lore.kernel.org/r/20240529164723.18309-2-tiwai@xxxxxxx Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- sound/core/ump.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/sound/core/ump.c b/sound/core/ump.c index fe7911498cc43..284d7b73fefd2 100644 --- a/sound/core/ump.c +++ b/sound/core/ump.c @@ -960,6 +960,14 @@ int snd_ump_parse_endpoint(struct snd_ump_endpoint *ump) if (err < 0) ump_dbg(ump, "Unable to get UMP EP stream config\n"); + /* If no protocol is set by some reason, assume the valid one */ + if (!(ump->info.protocol & SNDRV_UMP_EP_INFO_PROTO_MIDI_MASK)) { + if (ump->info.protocol_caps & SNDRV_UMP_EP_INFO_PROTO_MIDI2) + ump->info.protocol |= SNDRV_UMP_EP_INFO_PROTO_MIDI2; + else if (ump->info.protocol_caps & SNDRV_UMP_EP_INFO_PROTO_MIDI1) + ump->info.protocol |= SNDRV_UMP_EP_INFO_PROTO_MIDI1; + } + /* Query and create blocks from Function Blocks */ for (blk = 0; blk < ump->info.num_blocks; blk++) { err = create_block_from_fb_info(ump, blk); -- 2.43.0
