STRUCT DRM_OBJECT_PROPERTIES(9)

💅 struct drm_object_properties(9) 💅

okay so bestie, welcome to the Kernel API Manual — this one's all about struct drm_object_properties, and it's genuinely not as scary as it looks, i promise 🫶

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✨ NAME ✨

struct drm_object_properties — property tracking for &drm_mode_object 🎀

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🌸 SYNOPSIS 🌸

struct drm_object_properties {
    int count;
    struct drm_property *properties[DRM_OBJECT_MAX_PROPERTY];
    uint64_t values[DRM_OBJECT_MAX_PROPERTY];
 };

like, that's the whole vibe. three members. iconique. ✨

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🦋 Members 🦋

• count — the number of valid properties you've got going on. it must be less than or equal to DRM_OBJECT_MAX_PROPERTY. no cap, that's a hard limit 💀
• properties — an array of pointers to drm_property.

⚠️ NOTE: if we ever start dynamically destroying properties (ie. not at drm_mode_config_cleanup time), then we'd have to do a better job of detaching property from mode objects to avoid dangling property pointers. like, dangling pointers are not the move, bestie 😭

• values — the array that stores the property values, matching properties. and listen — do not read/write values directly, okay? use drm_object_property_get_value and drm_object_property_set_value instead. that's the whole point 🙈

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so here's the tea on atomic drivers ☕✨

atomic drivers do not store mutable properties in this array — they only keep the decoded values in the corresponding state structure. the decoding happens via these hooks:

• drm_crtc.atomic_get_property and drm_crtc.atomic_set_property — the hooks for struct drm_crtc
• drm_plane_funcs.atomic_get_property and drm_plane_funcs.atomic_set_property — the hooks for struct drm_plane
• drm_connector_funcs.atomic_get_property and drm_connector_funcs.atomic_set_property — the hooks for struct drm_connector

which means (and this is the important part, so pay attention 🔥): atomic drivers should not use drm_object_property_set_value and drm_object_property_get_value on mutable objects — i.e. those without the DRM_MODE_PROP_IMMUTABLE flag set. lowkey a big deal, don't skip it 💅

and one more thing bestie 🌈 — for atomic drivers, the default value of properties is stored in this array, so you can use drm_object_property_get_default_value to retrieve it. slay.

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👑 SEE ALSO 👑

• Kernel file ./include/drm/drm_mode_object.h
• struct drm_mode_object(9)

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mwah, that's the whole page 💖 this came from ./include/drm, October 2026 edition — go forth and track those properties, bestie, you got this 🧚‍♀️⭐