pci_vc_do_save_buffer(9)

📦 version 7.3.1, in nixpkgs unstable

💅 pci_vc_do_save_buffer(9) 💅

okay bestie, so this one's from the Kernel API Manual (section 9, kernel-space girlies only) and it's lowkey the multitasker of the PCI world — size, save, or restore VC state, all from one function. one function!! main character energy fr fr 🎀

✨ SYNOPSIS ✨

int pci_vc_do_save_buffer (struct pci_dev *dev , int pos , struct
       pci_cap_saved_state *save_state , bool save );

like yes, that's the whole signature, no cap. take a screenshot 📸

🦋 ARGUMENTS 🦋

  • dev — your device 💖 the whole reason we're here, honestly
  • pos — the starting position of the VC capability. and by VC we mean VC/VC9/MFVC — yes, all three flavors, she contains multitudes 🌈
  • save_state — the buffer for save/restore. it's giving "your canvas, your rules" 🎨
  • save — if you've provided a buffer, this lil bool tells us what to do with it. like, are we saving or restoring, bestie?? the bool knows 🫶

👑 DESCRIPTION 👑

okay so here's the vibe: walking Virtual Channel config space to size it, save it, or restore it is genuinely complicated — like, we're not gonna lie to you, it's a whole situation 😭 so instead of scattering that logic all over the place, we do it all from one function. reasons?

  • it reduces code (we're not out here writing the same thing forty times 💀)
  • and it guarantees the ordering matches in the buffer — which is the important part, ngl. consistent ordering or chaos, and we chose consistency ✨

now, the two modes, and this is the part to actually remember:

  1. Called with NULL save_state → she returns the size of the necessary save buffer. that's it. just the sizing, window-shopping style 🛍️
  2. Called with a non-NULL save_state → then save decides whether we save to the buffer or restore from it. your bool, your destiny 💅
no buffer? you get a number. buffer? you get action. that's the whole bit 🧚

🌸 SEE ALSO 🌸

the kernel file itself lives at ./drivers/pci/vc.c — go say hi 🫡 and while you're there, meet the whole friend group:

and that's the post 💜 this page ships out of ./drivers/pci and it's dated October 2026 — future-proofed AND slaying. mwah, go size some buffers bestie ⭐🍓

📦 where this page comes from