xe_guc_db_mgr_reserve_range(9)

💅 xe_guc_db_mgr_reserve_range(9) — from the Kernel API Manual, bestie

okay so picture this: we're in the kernel, the manual is literally called the Kernel API Manual, and today's main character is xe_guc_db_mgr_reserve_range(9). say it with me now 🎀

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✨ NAME ✨

xe_guc_db_mgr_reserve_range</p> — bestie, it reserves a range of GuC Doorbell IDs. that's the whole vibe. 🦋

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🌸 SYNOPSIS 🌸

int xe_guc_db_mgr_reserve_range (struct xe_guc_db_mgr *dbm , unsigned
       int count , unsigned int spare );

like, look at her. three little params and she's ready to go ✨

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💖 ARGUMENTS 💖

• dbm — the xe_guc_db_mgr. yes queen, that's the manager struct, she's the one holding it down 🫶
• count — number of GuC doorbell IDs to reserve. how many are we claiming? this many 💅
• spare — number of GuC doorbell IDs to keep available. gotta leave some for later, no cap 🔥

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🦋 DESCRIPTION 🦋

okay so this function is dedicated for the for use by the PF — yes, that's the original wording, i'm not touching it, iykyk 😭 — and the PF is out here expecting two things, literally:

1. that the allocated range for the VF will be contiguous. no gaps, no chaos, one clean block 💫
2. that there will be at least spare IDs still available for the PF's own use after this reservation goes through. self-care, honestly 🌸

so she grabs a chunk, keeps it tight, and leaves enough behind that the PF isn't left stranded. iconic behavior fr fr 👑

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⭐ RETURN ⭐

she returns the starting ID of the allocated GuC doorbell ID range — that's your entry point, bestie, that's where the whole block begins 🎀

or, if things go sideways: a negative error code on failure 💀 so like, always be checking. not me forgetting to check the return value 🙈

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🌈 SEE ALSO 🌈

• Kernel file ./drivers/gpu/drm/xe/xe_guc_db_mgr.c — the source, the mothership 🧚
• GuC Doorbells(9)
• xe_guc_db_mgr_init(9)
• xe_guc_db_mgr_reserve_id_locked(9)
• xe_guc_db_mgr_release_id_locked(9)
• xe_guc_db_mgr_release_range(9)
• xe_guc_db_mgr_print(9)

that's the whole friend group, go say hi to all of them 🫶✨

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ngl the doorbell manager is lowkey underrated and i will not be taking questions 💅

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and that's the page! brought to you by ./drivers/gpu/drm/xe in October 2026, for xe_guc_db_mgr_reserve_range(9) — mwah, study well, slay, periodt 💖🎀🔥