STRUCT VKMS_CRTC_STATE(9)

💅 struct vkms_crtc_state(9) 💅

okay bestie, welcome to the Kernel API Manual — this one's about struct vkms_crtc_state, and no cap, it's lowkey the main character of the VKMS driver. let's get into it ✨

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🌸 NAME 🌸

struct vkms_crtc_state — the driver-specific CRTC state. that's it, that's the vibe. 🎀

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🦋 SYNOPSIS 🦋

struct vkms_crtc_state {
    struct drm_crtc_state base;
    struct work_struct composer_work;
    int num_active_planes;
    struct vkms_plane_state **active_planes;
    struct vkms_writeback_job *active_writeback;
    struct vkms_color_lut gamma_lut;
    bool crc_pending;
    bool wb_pending;
    u64 frame_start;
    u64 frame_end;
 };

like, look at her. she's got range. 👑

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✨ Members ✨

• base — the base CRTC state, literally the foundation everything else sits on. 🫶
• composer_work — a work struct whose whole job is to compose stuff and add CRC entries. she's booked and busy.
• num_active_planes — how many planes are active rn, just a count. simple. iconic.
• active_planes — the list holding all the active planes (and yeah, the count matches num_active_planes). 🚨 important detail: they should be stored in z-order. don't skip that part, iykyk.
• active_writeback — the current active writeback job. the one on duty rn.
• gamma_lut — the look up table for gamma used in this CRTC. a whole little table of vibes. 🌈
• crc_pending — protected by vkms_output.composer_lock, and it's true when the frame CRC isn't computed yet. vblank peeks at this to detect if the composer is being too slow 😭 (yes, it's a snitch).
• wb_pending — also protected by vkms_output.composer_lock, and it's true when a writeback frame is requested. 💫
• frame_start — protected by vkms_output.composer_lock; it saves the frame number before the composition process starts. like a lil timestamp of "we began here".
• frame_end — protected by vkms_output.composer_lock; it saves the last requested frame number. this one's the MVP for generating enough CRC entries when the composition worker is too slow 🔥

heads up bestie: crc_pending, wb_pending, frame_start and frame_end are all under vkms_output.composer_lock. that's not a coincidence, that's a lock. 💀

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⭐ SEE ALSO ⭐

kernel file ./drivers/gpu/drm/vkms/vkms_drv.h, plus the whole friend group:

• struct vkms_frame_info(9)
• struct pixel_argb_u16(9)
• pixel_write_t(9)
• enum pixel_read_direction(9)
• pixel_read_line_t(9)
• struct conversion_matrix(9)
• struct vkms_plane_state(9)
• struct vkms_output(9)
• struct vkms_device(9)
• vkms_create(9)
• vkms_destroy(9)
• vkms_crtc_init(9)
• vkms_output_init(9)
• vkms_plane_init(9)

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that's the whole page, periodt 🎀 this drop came from ./drivers/gpu/drm/vkms, dated October 2026, and it's literally titled struct vkms_crtc_state(9). go forth and slay your CRTC state, bestie 💖🦋