STRUCT DRM_SCANOUT_BUFFER(9)

💖 struct drm_scanout_buffer(9) 💖

okay so bestie, this is a page straight outta the Kernel API Manual — struct drm_scanout_buffer(9) — and it's literally the main character of panic-screen rendering. sit down, grab a boba, we're learning 💅

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✨ NAME ✨

struct drm_scanout_buffer — the DRM scanout buffer, aka the thing that holds all the deets drm_panic needs to draw on your screen when everything else has gone 💀

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🎀 SYNOPSIS 🎀

struct drm_scanout_buffer {
    const struct drm_format_info *format;
    struct iosys_map map[DRM_FORMAT_MAX_PLANES];
    struct page **pages;
    unsigned int width;
    unsigned int height;
    unsigned int pitch[DRM_FORMAT_MAX_PLANES];
    void (*set_pixel)(struct drm_scanout_buffer *sb, unsigned int x,
unsigned int y, u32 color);
    void *private;
 };

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🦋 Members 🦋

• format — the drm format of the scanout buffer. like, what is this thing pixel-wise ✨
• map — virtual address of the scanout buffer, either in memory or iomem. this one's important: the scanout buffer should be in linear format, and it can be sent directly to the display hardware. and ngl, tearing is not an issue for the panic screen — so don't stress about it 🙈
• pages — optional! if the scanout buffer is not mapped, set this field to the array of pages of the scanout buffer. the panic code will use kmap_local_page_try_from_panic to map one page at a time to write all the pixels. 🫶

⚠️ heads up bestie: this array shouldn't be allocated from the get_scanoutbuffer callback. and yeah — the scanout buffer should be in linear format.

• width — width of the scanout buffer, in pixels 📏
• height — height of the scanout buffer, in pixels 📏
• pitch — length in bytes between the start of two consecutive lines. yes, a whole array of them 🌈
• set_pixel — optional function to set a pixel color on the framebuffer. it lets you handle special tiling format inside the driver 😤 and it takes precedence over the map and pages fields — so if it's set, it wins, periodt 👑
• private — private pointer that you can use in the callbacks set_pixel 🔒

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🌸 Description 🌸

This structure holds the information necessary for drm_panic to draw the panic screen, and display it. that's it, that's the vibe — it's giving "everything you need, nothing you don't" 💜

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⭐ SEE ALSO ⭐

Kernel file ./include/drm/drm_panic.h, drm_panic_trylock(9), drm_panic_lock(9), drm_panic_unlock(9) — go read those next, iykyk 🧚

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and that's the whole page, bestie!! 🎀 this little cutie lives in ./include/drm, the manual's dated October 2026, and it's brought to you by the Kernel API Manual — stream it, don't pirate it 💖✨🦋