drm_crtc_init(9)

🎀 drm_crtc_init(9) — the Kernel API Manual, bestie edition 🎀

okay so we're in the Kernel API Manual today and the vibe is legacy. Strap in, this one's a little retro but we're gonna make it make sense. 💅

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✨ NAME ✨

drm_crtc_init — the Legacy CRTC initialization function. yes, the word legacy is right there in the name, we'll get to that, don't panic 🫶

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🌸 SYNOPSIS 🌸

int drm_crtc_init (struct drm_device *dev , struct drm_crtc *crtc ,
       const struct drm_crtc_funcs *funcs );

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🦋 ARGUMENTS 🦋

• dev — the DRM device. the whole situation. the parent energy. 👑
• crtc — the CRTC object you're about to init, bestie. this is the one getting the glow-up.
• funcs — the callbacks for your brand-new CRTC. the personality pack, if you will. ✨

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💖 DESCRIPTION 💖

So what does it do? It initializes a CRTC object, and it hooks you up with a default helper-provided primary plane and no cursor plane. that's it, that's the whole vibe. no cursor. none. zero. 💀

now, the important part — and I need you to actually read this — it makes some assumptions about hardware limitations that, and I quote the energy here, may not be true for all hardware:

1. Primary plane cannot be repositioned. 🚫
2. Primary plane cannot be scaled. 🚫
3. Primary plane must cover the entire CRTC. 😤
4. Subpixel positioning is not supported. 🙈
5. The primary plane must always be on if the CRTC is enabled. ⚡

like... those are a lot of assumptions, and not every piece of hardware is gonna sign off on them, y'know? 😭

big note incoming: this is purely a backwards compatibility helper for old drivers. that's its whole job. it's giving "we keep it around for the elders." 🧓

Drivers should instead implement their own primary plane. and atomic drivers must do so. not "should", must. periodt. 🔥

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⭐ RETURN ⭐

Zero on success, an error code on failure. that's the whole return situation, slay. 💜

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🌈 SEE ALSO 🌈

go read these next, bestie, they're all connected iykyk:

• Kernel file ./drivers/gpu/drm/drm_modeset_helper.c
• aux kms helpers(9)
• drm_helper_move_panel_connectors_to_head(9)
• drm_helper_mode_fill_fb_struct(9)
• drm_mode_config_helper_suspend(9)
• drm_mode_config_helper_resume(9)

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and that's the page!! 🎀 mwah 💋 this little number lives over in ./drivers/gpu/drm, dated October 2026, and yes it's still filed under drm_crtc_init(9) — go forth and initialize responsibly, my love 🧚💖