iosf_mbi_write(9)

💖 NAME 💖

Hiii bestie!! Welcome to the Kernel API Manual page for iosf_mbi_write — aka the MailBox unmasked write command. 🎀 This is the lil' function that writes stuff into a mailbox register, and yes, it's giving main character energy. ✨

---

✨ SYNOPSIS ✨

int iosf_mbi_write (u8 port , u8 opcode , u32 offset , u32 mdr );

---

🦋 ARGUMENTS 🦋

• port — the port indicating which subunit is being accessed. It's literally telling you where the vibe check is happening. 👀
• opcode — the port specific read or write opcode. Port-specific, iykyk. 💅
• offset — the register address offset. Basically the address-y address of the register. 📍
• mdr — the register data to be written. This is the actual data going into the register, no cap. 💾

---

🌸 DESCRIPTION 🌸

Locking is handled by a spinlock — and it cannot sleep. Like, cannot sleep, periodt. 🛑😴 So don't be out here dreaming of snoozing inside this thing.

Locking is handled by spinlock - cannot sleep. Fr fr, do not even try it. 🚫💤

---

🌈 RETURN 🌈

Nonzero on error. That's the whole return vibe — if something goes wrong, you get a nonzero value back. 😭👍

---

👑 SEE ALSO 👑

• Kernel file: ./arch/x86/include/asm/iosf_mbi.h 🧚
• iosf_mbi_read(9)
• iosf_mbi_modify(9)
• iosf_mbi_punit_acquire(9)
• iosf_mbi_punit_release(9)
• iosf_mbi_block_punit_i2c_access(9)
• iosf_mbi_register_pmic_bus_access_notifier(9)
• iosf_mbi_unregister_pmic_bus_access_notifier_unlocked(9)
• iosf_mbi_assert_punit_acquired(9)

---

mwah 💋 this lil' page comes from ./arch/x86/include/asm, dated October 2026, and it's all about iosf_mbi_write(9) — bye bestie, slay your kernel adventures! 🫶💜