diff options
Diffstat (limited to 'Documentation/sound/designs/midi-2.0.rst')
| -rw-r--r-- | Documentation/sound/designs/midi-2.0.rst | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/Documentation/sound/designs/midi-2.0.rst b/Documentation/sound/designs/midi-2.0.rst index 45987f256b97..71a343c93fe7 100644 --- a/Documentation/sound/designs/midi-2.0.rst +++ b/Documentation/sound/designs/midi-2.0.rst @@ -74,8 +74,8 @@ topology based on those information. When the device is older and doesn't respond to the new UMP inquiries, the driver falls back and builds the topology based on Group Terminal Block (GTB) information from the USB descriptor. Some device might be screwed up by the -unexpected UMP command; in such a case, pass `midi2_probe=0` option to -snd-usb-audio driver for skipping the UMP v1.1 inquiries. +unexpected UMP command; in such a case, pass `midi2_ump_probe=0` +option to snd-usb-audio driver for skipping the UMP v1.1 inquiries. When the MIDI 2.0 device is probed, the kernel creates a rawmidi device for each UMP Endpoint of the device. Its device name is @@ -293,6 +293,17 @@ Rawmidi API Extensions status 0x05). When UMP core receives such a message, it updates the UMP EP info and the corresponding sequencer clients as well. +* The legacy rawmidi device number is found in the new `tied_device` + field of the rawmidi info. + On the other hand, the UMP rawmidi device number is found in + `tied_device` field of the legacy rawmidi info, too. + +* Each substream of the legacy rawmidi may be enabled / disabled + dynamically depending on the UMP FB state. + When the selected substream is inactive, it's indicated by the bit + 0x10 (`SNDRV_RAWMIDI_INFO_STREAM_INACTIVE`) in the `flags` field of + the legacy rawmidi info. + Control API Extensions ====================== @@ -377,6 +388,13 @@ Sequencer API Extensions announcement to the ALSA sequencer system port, similarly like the normal port change notification. +* There are two extended event types for notifying the UMP Endpoint and + Function Block changes via the system announcement port: + type 68 (`SNDRV_SEQ_EVENT_UMP_EP_CHANGE`) and type 69 + (`SNDRV_SEQ_EVENT_UMP_BLOCK_CHANGE`). They take the new type, + `snd_seq_ev_ump_notify` in the payload, indicating the client number + and the FB number that are changed. + MIDI2 USB Gadget Function Driver ================================ |