drivers/tty/vt/vc_screen.c

File Facts

System

Linux kernel

Corpus path

drivers/tty/vt/vc_screen.c

Extension

.c

Size

18144 bytes

Lines

807

Domain

Driver Families

Bucket

drivers/tty

Inferred role

Driver Families: operation-table or driver-model contract

Status

pattern 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.
• Defines an operation table; this is where Linux turns generic core objects into subsystem-specific behavior.
• Touches user memory; correctness depends on fault-safe copying and privilege boundary handling.
• 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/kernel.h
• linux/major.h
• linux/errno.h
• linux/export.h
• linux/tty.h
• linux/interrupt.h
• linux/mm.h
• linux/init.h
• linux/vt_kern.h
• linux/selection.h
• linux/kbd_kern.h
• linux/console.h
• linux/device.h
• linux/sched.h
• linux/fs.h
• linux/poll.h
• linux/signal.h
• linux/slab.h
• linux/notifier.h
• linux/uaccess.h
• asm/byteorder.h
• linux/unaligned.h

Detected Declarations

• struct vcs_poll_data
• function vcs_notifier
• function vcs_poll_data_free
• function vcs_poll_data_get
• function vcs_size
• function vcs_lseek
• function scoped_guard
• function vcs_read_buf_uni
• function vcs_read_buf_noattr
• function vcs_read_buf
• function vcs_read
• function Compilers
• function vcs_write
• function vcs_poll
• function vcs_fasync
• function vcs_open
• function vcs_release
• function vcs_make_sysfs
• function vcs_remove_sysfs
• function vcs_init

Annotated Snippet

static const struct file_operations vcs_fops = {
	.llseek		= vcs_lseek,
	.read		= vcs_read,
	.write		= vcs_write,
	.poll		= vcs_poll,
	.fasync		= vcs_fasync,
	.open		= vcs_open,
	.release	= vcs_release,
};

static const struct class vc_class = {
	.name = "vc",
};

void vcs_make_sysfs(int index)
{
	device_create(&vc_class, NULL, MKDEV(VCS_MAJOR, index + 1), NULL, "vcs%u", index + 1);
	device_create(&vc_class, NULL, MKDEV(VCS_MAJOR, index + 65), NULL, "vcsu%u", index + 1);
	device_create(&vc_class, NULL, MKDEV(VCS_MAJOR, index + 129), NULL, "vcsa%u", index + 1);
}

void vcs_remove_sysfs(int index)
{
	device_destroy(&vc_class, MKDEV(VCS_MAJOR, index + 1));
	device_destroy(&vc_class, MKDEV(VCS_MAJOR, index + 65));
	device_destroy(&vc_class, MKDEV(VCS_MAJOR, index + 129));
}

int __init vcs_init(void)
{
	unsigned int i;

	if (register_chrdev(VCS_MAJOR, "vcs", &vcs_fops))
		panic("unable to get major %d for vcs device", VCS_MAJOR);
	if (class_register(&vc_class))
		panic("unable to create vc_class");

	device_create(&vc_class, NULL, MKDEV(VCS_MAJOR, 0), NULL, "vcs");
	device_create(&vc_class, NULL, MKDEV(VCS_MAJOR, 64), NULL, "vcsu");
	device_create(&vc_class, NULL, MKDEV(VCS_MAJOR, 128), NULL, "vcsa");
	for (i = 0; i < MIN_NR_CONSOLES; i++)
		vcs_make_sysfs(i);
	return 0;
}

Annotation

• Immediate include surface: `linux/kernel.h`, `linux/major.h`, `linux/errno.h`, `linux/export.h`, `linux/tty.h`, `linux/interrupt.h`, `linux/mm.h`, `linux/init.h`.
• Detected declarations: `struct vcs_poll_data`, `function vcs_notifier`, `function vcs_poll_data_free`, `function vcs_poll_data_get`, `function vcs_size`, `function vcs_lseek`, `function scoped_guard`, `function vcs_read_buf_uni`, `function vcs_read_buf_noattr`, `function vcs_read_buf`.
• Atlas domain: Driver Families / drivers/tty.
• Implementation status: pattern implementation candidate.
• This snippet crosses the user/kernel memory boundary; validate fault handling and access checks before translating the pattern.
• 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.