pci_write_legacy_io(9)

🌸 NAME 🌸

pci_write_legacy_io — write byte(s) to legacy I/O port space. This is the pci_write_legacy_io(9) page from the Kernel API Manual, bestie, and it’s giving tiny-but-important sysfs energy 💅✨

📜 SYNOPSIS 📜

       ssize_t pci_write_legacy_io (struct file *filp , struct kobject *kobj ,
       const struct bin_attribute *bin_attr , char *buf , loff_t off , size_t
       count );

🧚 ARGUMENTS 🧚

• filp — an open sysfs file. Main-character file handle vibes 🫶
• kobj — the kobject corresponding to the file to read from. (Yes, it says “read from” — we’re just relaying the manual tea 🫖)
• bin_attr — the struct bin_attribute for this file.
• buf — the buffer containing the value to be written.
• off — the offset into legacy I/O port space.
• count — the number of bytes to write.

💖 DESCRIPTION 💖

Okay so this one writes 1, 2, or 4 bytes from legacy I/O port space using an arch specific callback routine (pci_legacy_write). That’s the whole lore. No cap. 🔥

👑 SEE ALSO 👑

Kernel file: ./drivers/pci/pci-sysfs.c

• pci_read_legacy_io(9)
• pci_mmap_legacy_mem(9)
• pci_mmap_legacy_io(9)
• pci_mmap_resource(9)
• pci_write_rom(9)
• pci_read_rom(9)

okay bestie, that’s the whole pci_write_legacy_io(9) page 💖 it lives under ./drivers/pci, it’s dated October 2026, and that’s the Kernel API Manual sign-off. periodt ✨🦋🎀