STRUCT EM28XX_BUFFER(9)

💖 struct em28xx_buffer(9) 💖

okay so bestie, welcome to the Kernel API Manual ✨ — today's main character is struct em28xx_buffer, and honestly? it's giving "one video frame's whole support system." let's get into it 🎀

---

🌸 NAME 🌸

struct em28xx_buffer — the buffer that holds one (1) single video frame, no more no less 🦋

---

✨ SYNOPSIS ✨

struct em28xx_buffer {
    struct vb2_v4l2_buffer  vb;
    struct list_head        list;
    void *mem;
    unsigned int            length;
    int top_field;
    unsigned int            pos;
    char *vb_buf;
 };

like, that's the whole vibe right there. copy it exactly if you're writing code, i'm begging 🙈

---

🫶 Members 🫶

• vb — the common v4l buffer stuff. literally the standard-issue V4L2 buffer bits living inside this thing 💅
• list — a list head so this buffer can link up with all the other buffers. it's a group chat, and every buffer is in it 😭
• mem — pointer to the buffer itself, as returned by vb2_plane_vaddr. that's where the actual memory lives ✨
• length — how long the buffer is, as returned by vb2_plane_size. the size check, the vibe check 🎀
• top_field — if this is non-zero, it means the buffer is the top field. that's it, that's the flag 👑
• pos — tells you the next position in the buffer that's gonna get filled. the "we're up to here" marker 🔥
• vb_buf — pointer to the vmalloc memory address in vb. lowkey the real address energy ⭐

---

💀 Description 💀

NOTE: in interlaced mode, pos gets reset to zero at the start of each new field — not frame! 🚨 like please do not get this twisted, the field/frame distinction is doing so much work here. fields are the little guys; frames are the big picture. pos starts over per field. periodt 💅

---

🌈 SEE ALSO 🌈

• Kernel file ./drivers/media/usb/em28xx/em28xx.h
• struct em28xx_usb_bufs(9)
• struct em28xx_usb_ctl(9)
• struct em28xx_fmt(9)
• enum em28xx_amux(9)

go read those next, iykyk 🧚

---

and that's the whole page bestie, no cap 🍓 — this one came from ./drivers/media/usb/em28xx, dated October 2026, and it's struct em28xx_buffer(9) saying bye 💜🦋