msi_first_desc(9)

💅 msi_first_desc(9) — like, the Kernel API Manual era 🎀

okay bestie, sit down, we're talking about msi_first_desc(9) today and honestly? she's a little lookup girlie with one very important rule. let's get into it ✨

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🌸 NAME 🌸

msi_first_desc — grabbeth the first MSI descriptor of the default irqdomain. yes, THE default one. main character irqdomain energy 💅

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✨ SYNOPSIS ✨

struct msi_desc * msi_first_desc (struct device *dev , enum
msi_desc_filter filter );

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🦋 ARGUMENTS 🦋

• dev — the Device you're operating on 🫶 like, whose descriptors are we digging through, bestie?
• filter — the Descriptor state filter 🎀 you get to be picky. iconic of you.

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💖 DESCRIPTION 💖

okay so this is the part where you HAVE to listen, no cap:

Must be called with the MSI descriptor mutex held, i.e. msi_lock_descs must be invoked before the call. 😭

like, LITERALLY. you cannot just waltz in and call this thing cold. msi_lock_descs goes first, then you call. that's the vibe check and you WILL be failing it if you skip the lock. lock her up first, then go looking. periodt 🔥

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👑 RETURN 👑

returns a Pointer to the first MSI descriptor matching the search criteria 💫

and if nothing matches? NULL 🫠 none found, bestie. empty search. it's giving nothing in the group chat. 🌈

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🔥 SEE ALSO 🔥

the whole squad, fr fr — Kernel file ./include/linux/msi.h, plus:

• struct msi_msg(9)
• struct pci_msi_desc(9)
• union msi_domain_cookie(9)
• struct msi_desc_data(9)
• struct msi_desc(9)
• struct msi_dev_domain(9)
• msi_domain_for_each_desc(9)
• msi_for_each_desc(9)
• msi_msg_set_addr(9)
• msi_insert_msi_desc(9)
• msi_free_msi_descs_range(9)
• msi_free_msi_descs(9)
• struct msi_domain_ops(9)
• struct msi_domain_info(9)
• struct msi_domain_template(9)
• struct msi_parent_ops(9)

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and that's the whole page, bestie 🧚 this one lives over in ./include/linux and it's dated October 2026 — so yeah, mark your calendars, the Kernel API Manual said what it said 💜💅