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This patch adds the support helpers for UMP (Universal MIDI Packet) in ALSA core. The basic design is that a rawmidi instance is assigned to each UMP Endpoint. A UMP Endpoint provides a UMP stream, typically bidirectional (but can be also uni-directional, too), which may hold up to 16 UMP Groups, where each UMP (input/output) Group corresponds to the traditional MIDI I/O Endpoint. Additionally, the ALSA UMP abstraction provides the multiple UMP Blocks that can be assigned to each UMP Endpoint. A UMP Block is a metadata to hold the UMP Group clusters, and can represent the functions assigned to each UMP Group. A typical implementation of UMP Block is the Group Terminal Blocks of USB MIDI 2.0 specification. For distinguishing from the legacy byte-stream MIDI device, a new device "umpC*D*" will be created, instead of the standard (MIDI 1.0) devices "midiC*D*". The UMP instance can be identified by the new rawmidi info bit SNDRV_RAWMIDI_INFO_UMP, too. A UMP rawmidi device reads/writes only in 4-bytes words alignment, stored in CPU native endianness. The transmit and receive functions take care of the input/out data alignment, and may return zero or aligned size, and the params ioctl may return -EINVAL when the given input/output buffer size isn't aligned. A few new UMP-specific ioctls are added for obtaining the new UMP endpoint and block information. As of this commit, no ALSA sequencer instance is attached to UMP devices yet. They will be supported by later patches. Along with those changes, the protocol version for rawmidi is bumped to 2.0.3. Reviewed-by: Jaroslav Kysela <perex@perex.cz> Link: https://lore.kernel.org/r/20230523075358.9672-4-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de> |
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| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
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| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.