__drm_gem_du..._plane_state(9)

💅 NAME 💅

Hiii bestie, welcome to the <pink>Kernel API Manual</pink> page for __drm_gem_duplicate_shadow_plane_state — the function whose whole entire job is <purple>duplicating shadow-buffered plane state</purple>. Yes that's the whole name. Yes it's a mouthful. We stan anyway. 🎀

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✨ SYNOPSIS ✨

void __drm_gem_duplicate_shadow_plane_state (struct drm_plane *plane ,
       struct drm_shadow_plane_state *new_shadow_plane_state );

Like... look at her. <cyan>void</cyan>, two args, no notes. Iconic behavior honestly. 🫶

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🌸 ARGUMENTS 🌸

• plane — the plane. That's it. That's the description. She's the <hotpink>main character</hotpink> of this call, literally the thing being duplicated from. 💅
• new_shadow_plane_state — the new shadow-buffered plane state, i.e. the <mint>fresh copy</mint> that's about to be all filled in. Destination vibes only. ✨

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🦋 DESCRIPTION 🦋

Okay so, real talk: this function <green>duplicates shadow-buffered plane state</green>. Full stop, that's the assignment, and she ate. 🍓

Who is this for, you ask? It's <yellow>helpful for drivers that subclass struct drm_shadow_plane_state</yellow> — so if your driver is doing the subclass thing, this is your girl. iykyk. 👑

Now here's the part you <red>cannot</red> skip, bestie, pay attention:

This function <bold>does not</bold> duplicate existing mappings of the shadow buffers. Not a single one. Zero. Nada. 🙈

So where do the mappings actually get maintained? During the <purple>atomic commit</purple>, babes — handled by the plane's prepare_fb and cleanup_fb helpers. If you want the corresponding helper lore, go look at drm_gem_prepare_shadow_fb and drm_gem_cleanup_shadow_fb. Those two are carrying the team fr fr. 💀

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🔥 SEE ALSO 🔥

Lowkey the whole squad shows up here, so let me introduce everyone:

• Kernel file ./drivers/gpu/drm/drm_gem_atomic_helper.c — and also overview(9), the big-picture baddie 🌈
• drm_gem_plane_helper_prepare_fb(9)
• drm_gem_duplicate_shadow_plane_state(9)
• __drm_gem_destroy_shadow_plane_state(9)
• drm_gem_destroy_shadow_plane_state(9)
• __drm_gem_reset_shadow_plane(9)
• drm_gem_reset_shadow_plane(9)
• drm_gem_begin_shadow_fb_access(9)
• drm_gem_end_shadow_fb_access(9)
• drm_gem_simple_kms_begin_shadow_fb_access(9)
• drm_gem_simple_kms_end_shadow_fb_access(9)
• drm_gem_simple_kms_reset_shadow_plane(9)
• drm_gem_simple_kms_duplicate_shadow_plane_state(9)
• drm_gem_simple_kms_destroy_shadow_plane_state(9)

Not a single one left behind. We don't do that here. 💖

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Okay that's the whole page, bestie! This lil' beauty lives in the <bold>./drivers/gpu/drm</bold> corner of the kernel and it was stamped October 2026 — so mark your calendar and go duplicate some plane state responsibly. Mwah! 💋✨🎀