STRUCT PCI_BRIDGE_REG_BEHAVIOR(9)

🎀 NAME 🎀

okay so bestie, this whole page is about struct pci_bridge_reg_behavior — register bits behaviors 💅. It's part of the Kernel API Manual, and the page title is literally struct pci_bridge_reg_behavior(9).

✨ SYNOPSIS ✨

Here's the struct, served fresh and exact:

       struct pci_bridge_reg_behavior {
           u32 ro;
           u32 rw;
           u32 w1c;
        };

🫶 Members 🫶

• ro — Read-Only bits. Look but do not touch, bestie 🫶.
• rw — Read-Write bits. Read 'em, write 'em, slay ✨.
• w1c — Write-1-to-Clear bits. The name says it all, iykyk 💅.

💖 DESCRIPTION 💖

Reads and Writes will be filtered by specified behavior. All other bits not declared are assumed 'Reserved' and will return 0 on reads. That's not me being dramatic — it's per PCIe 5.0:

"Reserved register fields must be read only and must return 0 (all 0's for multi-bit fields) when read".

So yeah, the undeclared bits are Reserved with a capital R, and they give you 0 when read 😭👑.

🌈 SEE ALSO 🌈

• Kernel file ./drivers/pci/pci-bridge-emul.c — the lore is right there, go read it 👀📖.

💜 xoxo, bestie — source/version: ./drivers/pci · date: October 2026 · footer title: struct pci_b...reg_behavior(9).