sound/drivers/aloop.c

File Facts

System

Linux kernel

Corpus path

sound/drivers/aloop.c

Extension

.c

Size

55079 bytes

Lines

1922

Domain

Driver Families

Bucket

sound/drivers

Inferred role

Driver Families: exported/initcall integration point

Status

integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

• Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.
• Exports symbols or registers init work; inspect boot/module ordering and who consumes the exported contract.
• Uses kernel synchronization; read lock ordering, sleepability, and interrupt context assumptions before translating.
• Allocates kernel memory; connect allocation flags and lifetime to context constraints.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/init.h
• linux/jiffies.h
• linux/slab.h
• linux/string.h
• linux/time.h
• linux/wait.h
• linux/module.h
• linux/platform_device.h
• sound/core.h
• sound/control.h
• sound/pcm.h
• sound/pcm_params.h
• sound/info.h
• sound/initval.h
• sound/timer.h

Detected Declarations

• struct loopback_cable
• struct loopback_pcm
• struct loopback_ops
• struct loopback_cable
• struct loopback_setup
• struct loopback
• struct loopback_pcm
• function byte_pos
• function frac_pos
• function get_notify
• function get_rate_shift
• function loopback_jiffies_timer_start
• function loopback_snd_timer_start
• function loopback_jiffies_timer_stop
• function loopback_snd_timer_stop
• function loopback_jiffies_timer_stop_sync
• function loopback_snd_timer_close_cable
• function is_access_interleaved
• function loopback_check_format
• function scoped_guard
• function loopback_active_notify
• function loopback_trigger
• function scoped_guard
• function scoped_guard
• function scoped_guard
• function scoped_guard
• function params_change
• function loopback_prepare
• function clear_capture_buf
• function copy_play_buf_part_n
• function copy_play_buf
• function snd_pcm_playback_hw_avail
• function bytepos_delta
• function bytepos_finish
• function loopback_jiffies_timer_pos_update
• function loopback_jiffies_timer_function
• function scoped_guard
• function loopback_snd_timer_check_resolution
• function loopback_snd_timer_period_elapsed
• function scoped_guard
• function loopback_snd_timer_function
• function loopback_snd_timer_work
• function loopback_snd_timer_event
• function loopback_jiffies_timer_dpcm_info
• function loopback_snd_timer_dpcm_info
• function loopback_pointer
• function loopback_runtime_free
• function loopback_hw_free

Annotated Snippet

module_init(alsa_card_loopback_init)
module_exit(alsa_card_loopback_exit)

Annotation

• Immediate include surface: `linux/init.h`, `linux/jiffies.h`, `linux/slab.h`, `linux/string.h`, `linux/time.h`, `linux/wait.h`, `linux/module.h`, `linux/platform_device.h`.
• Detected declarations: `struct loopback_cable`, `struct loopback_pcm`, `struct loopback_ops`, `struct loopback_cable`, `struct loopback_setup`, `struct loopback`, `struct loopback_pcm`, `function byte_pos`, `function frac_pos`, `function get_notify`.
• Atlas domain: Driver Families / sound/drivers.
• Implementation status: integration implementation candidate.
• Synchronization appears in or near this file; preserve lock ordering, sleepability, and interrupt-context constraints.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.