drivers/video/console/dummycon.c

File Facts

System

Linux kernel

Corpus path

drivers/video/console/dummycon.c

Extension

.c

Size

4039 bytes

Lines

160

Domain

Driver Families

Bucket

drivers/video

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.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/types.h
• linux/kdev_t.h
• linux/console.h
• linux/vt_kern.h
• linux/screen_info.h
• linux/init.h
• linux/module.h
• asm/vga.h

Detected Declarations

• function dummycon_register_output_notifier
• function dummycon_unregister_output_notifier
• function dummycon_putc
• function dummycon_putcs
• function dummycon_blank
• function dummycon_switch
• function dummycon_putc
• function dummycon_switch
• function dummycon_init
• function dummycon_deinit
• export dummy_con

Annotated Snippet

if (init) {
	vc->vc_cols = DUMMY_COLUMNS;
	vc->vc_rows = DUMMY_ROWS;
    } else
	vc_resize(vc, DUMMY_COLUMNS, DUMMY_ROWS);
}

static void dummycon_deinit(struct vc_data *vc) { }
static void dummycon_clear(struct vc_data *vc, unsigned int sy, unsigned int sx,
			   unsigned int width) { }
static void dummycon_cursor(struct vc_data *vc, bool enable) { }

static bool dummycon_scroll(struct vc_data *vc, unsigned int top,
			    unsigned int bottom, enum con_scroll dir,
			    unsigned int lines)
{
	return false;
}

/*
 *  The console `switch' structure for the dummy console
 *
 *  Most of the operations are dummies.
 */

const struct consw dummy_con = {
	.owner =		THIS_MODULE,
	.con_startup =	dummycon_startup,
	.con_init =		dummycon_init,
	.con_deinit =	dummycon_deinit,
	.con_clear =	dummycon_clear,
	.con_putc =		dummycon_putc,
	.con_putcs =	dummycon_putcs,
	.con_cursor =	dummycon_cursor,
	.con_scroll =	dummycon_scroll,
	.con_switch =	dummycon_switch,
	.con_blank =	dummycon_blank,
};
EXPORT_SYMBOL_GPL(dummy_con);

Annotation

• Immediate include surface: `linux/types.h`, `linux/kdev_t.h`, `linux/console.h`, `linux/vt_kern.h`, `linux/screen_info.h`, `linux/init.h`, `linux/module.h`, `asm/vga.h`.
• Detected declarations: `function dummycon_register_output_notifier`, `function dummycon_unregister_output_notifier`, `function dummycon_putc`, `function dummycon_putcs`, `function dummycon_blank`, `function dummycon_switch`, `function dummycon_putc`, `function dummycon_switch`, `function dummycon_init`, `function dummycon_deinit`.
• Atlas domain: Driver Families / drivers/video.
• Implementation status: integration implementation candidate.

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.