drm_atomic_helper_dirtyfb(9)

💅 drm_atomic_helper_dirtyfb(9) — Kernel API Manual 🎀

okay so bestie, we're in the Kernel API Manual today and the star of the show is drm_atomic_helper_dirtyfb. she's a helper. she does dirtyfb. that's the whole vibe. let's get into it ✨

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✨ NAME ✨

drm_atomic_helper_dirtyfb — literally the helper for dirtyfb. that's it. that's her whole job description and she's slaying it 💅

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🦋 SYNOPSIS 🦋

int drm_atomic_helper_dirtyfb (struct drm_framebuffer *fb , struct
       drm_file *file_priv , unsigned int flags , unsigned int color , struct
       drm_clip_rect *clips , unsigned int num_clips );

six arguments, one int coming back at you. iconic signature, no notes 🫶

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🌸 ARGUMENTS 🌸

• fb — the DRM framebuffer, aka the main character 💖
• file_priv — the DRM file for the ioctl call. she's the receipts 🧾
• flags — dirty fb annotate flags 🌈
• color — color for the annotate fill 🎨
• clips — the dirty region, spill the tea about which bits changed 🍓
• num_clips — count of clip in clips. yes, keep track bestie 🔢

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🔥 DESCRIPTION 🔥

so this is a helper to implement drm_framebuffer_funcs.dirty using the damage interface during plane update. ngl that's a lot of words, but it means: you hand her the damage info and she handles the dirty-ing for you 😌

here's the important bit — if num_clips is 0, then this helper will do a full plane update. and this is the same behaviour expected by the DIRTFB IOCTL, so like, no surprises, fr fr ✨

also note, this helper is a blocking implementation 🚨 that's not a bug, that's the point. this is what current drivers and userspace expect in their DIRTFB IOCTL implementation, as a way to rate-limit userspace and make sure its rendering doesn't get ahead of uploading new data too much. she's literally holding the line so nobody sprints ahead 💀👑

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⭐ RETURN ⭐

• zero on success 🎉 slay
• negative errno on failure 😭 it's giving error vibes

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👑 SEE ALSO 👑

• Kernel file ./drivers/gpu/drm/drm_damage_helper.c
• drm_atomic_helper_check_plane_damage(9)
• drm_atomic_helper_damage_iter_init(9)
• drm_atomic_helper_damage_iter_next(9)
• drm_atomic_helper_damage_merged(9)

go read those next, they're all in the same friend group 🫶

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and that's the whole page bestie!! 💖 this absolute queen lives at ./drivers/gpu/drm, dated October 2026, and yes, this is the drm_atomic_helper_dirtyfb(9) manual. mwah 💋✨