STRUCT DRM_MODE_CREATE_DUMB(9)

✨ NAME ✨

okay so bestie, welcome to struct drm_mode_create_dumb(9) from the Kernel API Manual — this is the struct for creating a KMS dumb buffer for scanout. It's giving "simple buffer, but make it display-ready," no cap. 💅✨

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🌸 SYNOPSIS 🌸

struct drm_mode_create_dumb {
    __u32 height;
    __u32 width;
    __u32 bpp;
    __u32 flags;
    __u32 handle;
    __u32 pitch;
    __u64 size;
};

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🫶 Members 🫶

• height — buffer height in pixels.
• width — buffer width in pixels.
• bpp — color mode.
• flags — must be zero. Literally zero, bestie. 🚨
• handle — buffer object handle.
• pitch — number of bytes between two consecutive lines.
• size — size of the whole buffer in bytes.

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💖 DESCRIPTION 💖

User-space fills height, width, bpp and flags. If the IOCTL succeeds, the kernel fills handle, pitch and size. That's the whole trade, iykyk. 🫶

The value of bpp is a color-mode number describing a specific format or a variant thereof. The value often corresponds to the number of bits per pixel for most modes — although, yes, there are exceptions. Each color mode maps to a DRM format plus a number of modes with similar pixel layout. Framebuffer layout is always linear. 🌈

Support for all modes and formats is optional. Even if dumb-buffer creation with a certain color mode succeeds, it is not guaranteed that the DRM driver supports any of the related formats. Most drivers support a color mode of 32 with a format of DRM_FORMAT_XRGB8888 on their primary plane. ✨

Here's the color-mode tea, fr fr: 🍓

• Color mode 32 — framebuffer format: DRM_FORMAT_XRGB8888; compatible formats: DRM_FORMAT_BGRX8888, DRM_FORMAT_RGBX8888, DRM_FORMAT_XBGR8888.
• Color mode 24 — framebuffer format: DRM_FORMAT_RGB888; compatible formats: DRM_FORMAT_BGR888.
• Color mode 16 — framebuffer format: DRM_FORMAT_RGB565; compatible formats: DRM_FORMAT_BGR565.
• Color mode 15 — framebuffer format: DRM_FORMAT_XRGB1555; compatible formats: DRM_FORMAT_BGRX1555, DRM_FORMAT_RGBX1555, DRM_FORMAT_XBGR1555.
• Color mode 8 — framebuffer format: DRM_FORMAT_C8; compatible formats: DRM_FORMAT_D8, DRM_FORMAT_R8.
• Color mode 4 — framebuffer format: DRM_FORMAT_C4; compatible formats: DRM_FORMAT_D4, DRM_FORMAT_R4.
• Color mode 2 — framebuffer format: DRM_FORMAT_C2; compatible formats: DRM_FORMAT_D2, DRM_FORMAT_R2.
• Color mode 1 — framebuffer format: DRM_FORMAT_C1; compatible formats: DRM_FORMAT_D1, DRM_FORMAT_R1.

⚠️ Color modes of 10, 12, 15, 30 and 64 are only supported for use by legacy user space. Please don't use them in new code. Other modes are not support. 😭

🚨 Do not attempt to allocate anything but linear framebuffer memory with single-plane RGB data. Allocation of other framebuffer layouts requires dedicated ioctls in the respective DRM driver. That part is not a vibe-check situation, it's a hard boundary. 💀

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🔥 SEE ALSO 🔥

• Kernel file ./include/uapi/drm/drm_mode.h overview(9)
• struct drm_mode_modeinfo(9)
• struct drm_mode_get_plane(9)
• struct drm_mode_get_connector(9)
• struct drm_mode_property_enum(9)
• struct drm_mode_get_property(9)
• struct drm_mode_fb_cmd2(9)
• enum drm_colorop_type(9)
• enum drm_colorop_lut3d_interpolation_type(9)
• enum drm_colorop_lut1d_interpolation_type(9)
• struct drm_plane_size_hint(9)
• struct hdr_metadata_infoframe(9)
• struct hdr_output_metadata(9)
• DRM_MODE_PAGE_FLIP_EVENT(9)
• DRM_MODE_PAGE_FLIP_ASYNC(9)
• DRM_MODE_PAGE_FLIP_FLAGS(9)
• DRM_MODE_ATOMIC_TEST_ONLY(9)
• DRM_MODE_ATOMIC_NONBLOCK(9)
• DRM_MODE_ATOMIC_ALLOW_MODESET(9)
• DRM_MODE_ATOMIC_FLAGS(9)
• struct drm_mode_create_blob(9)
• struct drm_mode_destroy_blob(9)
• struct drm_mode_create_lease(9)
• struct drm_mode_list_lessees(9)
• struct drm_mode_get_lease(9)
• struct drm_mode_revoke_lease(9)
• struct drm_mode_rect(9)
• struct drm_mode_closefb(9)

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Sign-off tea ☕: this page comes from ./include/uapi/drm, dated October 2026, and its manual identity is struct drm_mode_create_dumb(9). Slay, go make that dumb buffer. 💅🎀