STRUCT VMW_DU_UPDATE_PLANE(9)

💅 struct vmw_du_update_plane(9)

hiii bestie, welcome to the Kernel API Manual ✨ this one's about struct vmw_du_update_plane, and ngl it's giving "backstage pass to a plane update". let's get into it 🫶

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✨ NAME ✨

struct vmw_du_update_plane — the closure structure for vmw_du_helper_plane_update 💫 like, the little bundle of function pointers and state that makes the helper do its thing.

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🎀 SYNOPSIS 🎀

struct vmw_du_update_plane {
    uint32_t (*calc_fifo_size)(struct vmw_du_update_plane *update,
uint32_t num_hits);
    uint32_t (*post_prepare)(struct vmw_du_update_plane *update, void
*cmd);
    uint32_t (*pre_clip)(struct vmw_du_update_plane *update, void *cmd,
uint32_t num_hits);
    uint32_t (*clip)(struct vmw_du_update_plane *update, void *cmd,
struct drm_rect *clip, uint32_t src_x, uint32_t src_y);
    uint32_t (*post_clip)(struct vmw_du_update_plane *update, void *cmd,
struct drm_rect *bb);
    struct drm_plane *plane;
    struct drm_plane_state *old_state;
    struct vmw_private *dev_priv;
    struct vmw_display_unit *du;
    struct vmw_framebuffer *vfb;
    struct vmw_fence_obj **out_fence;
    struct mutex *mutex;
    bool intr;
 };

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💜 MEMBERS 💜

okay so here's the whole cast, one iconic member at a time 👑

calc_fifo_size

Calculate fifo size. 🧮

Figure out the fifo size you need for the commands that the update requires. The number of damage clips on the display unit — that's num_hits — gets passed in so you can allocate enough fifo space.

Return: the fifo size you need ⭐

post_prepare

Populate fifo for resource preparation. 🛠️

Some surface resources or buffer objects need a little extra cmd submission, like updating the GB image for a proxy surface, or defining a GMRFB for a screen object. That's the vibe here — this callback fires after the FIFO allocation, and it gets handed the address of the command buffer.

This callback is optional. no pressure 💅

Return: the size of the commands populated into the command buffer.

pre_clip

Populate fifo before clip. 🌸

This is where your pre-clip-related commands go — surface copy/DMA and friends, etc.

This callback is optional.

Return: the size of the commands populated into the command buffer.

clip

Populate fifo for clip. ✂️

This is the spot where you populate clips for surface copy/dma or blit commands, if you need them. It gets called however many times there's damage in the display unit — which is one time if you're doing a full update. clip is the damage in destination coordinates (that's crtc/DU), and src_x, src_y are the damage clip's source in framebuffer coordinates.

This callback is optional.

Return: the size of the commands populated into the command buffer.

post_clip

Populate fifo after clip. 🦋

This is where you populate the display unit update commands, or the blit commands.

Return: the size of the commands populated into the command buffer.

plane

The plane that's being updated. ✈️ main character energy fr.

old_state

The old state of the plane. 🕰️

dev_priv

Device private. 🔒

du

The display unit on which the plane gets updated. 🖥️

vfb

The framebuffer that's blitted to the display unit. 🖼️

out_fence

Out fence for resource finish. 🏁

mutex

The mutex used to protect resource reservation. 🔐

intr

Whether to perform waits interruptible if possible. 😴 (yes, if possible!)

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🌈 DESCRIPTION 🌈

okay so this structure loosely represents the set of operations you need to perform a plane update on a display unit. whoever's implementing it defines that functionality according to this structure's function callbacks. in brief — and I do mean in brief — it involves surface/buffer object validation, populating FIFO commands, and submitting commands to the device. that's the whole arc, start to finish 💫

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👀 SEE ALSO 👀

Kernel file ./drivers/gpu/drm/vmwgfx/vmwgfx_kms.h — plus these cuties, go read them too:

• struct vmw_du_update_plane_surface(9)
• struct vmw_du_update_plane_buffer(9)
• struct vmw_kms_dirty(9)
• vmw_du_translate_to_crtc(9)

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ngl the fifo is the whole plot here. allocate it right, bestie, or the commands simply will not fit 💀

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and that's the page!! 🎀 brought to you by ./drivers/gpu/drm/vmwgfx, dated October 2026, and yeah — the header said struct vmw_du_update_plane(9) and the footer said the same, so we've come full circle 🫶 slay, go update some planes ✨💖