pcie_enable_tph(9)

💖 pcie_enable_tph(9) — the kernel API manual, but make it cute 💖

okay so bestie, this is a page from the Kernel API Manual, and it's about one tiny little function that turns on something called TPH — you know those Transaction Layer Packet Processing Hints? no? doesn't matter, we're gonna get you through it 🫶

---

✨ NAME ✨

pcie_enable_tph — literally just Enable TPH support for device using a specific ST mode. that's the whole vibe 💅

---

🌸 SYNOPSIS 🌸

int pcie_enable_tph (struct pci_dev *pdev , int mode );

like, that's it. two arguments, one int back. iconic.

---

🎀 ARGUMENTS 🎀

• pdev — the PCI device you're doing this to. your main character, if you will 👑
• mode — the ST mode you wanna enable. Current supported modes include: (and yeah they're listed in the DESCRIPTION section below, keep scrolling bestie, i got you 💜)

---

🦋 DESCRIPTION 🦋

so the modes. there are three. here they are:

• PCI_TPH_ST_NS_MODE — NO ST Mode 😌
• PCI_TPH_ST_IV_MODE — Interrupt Vector Mode ⚡
• PCI_TPH_ST_DS_MODE — Device Specific Mode 🧚

and what the function does, like actually:

• it checks whether the mode is actually supported by the device before enabling it, and it returns an error if not. so no, you can't just ask for a random mode and hope for the best — that's a vibe check it will fail 💀
• additionally, it determines what types of requests, TPH or extended TPH, can be issued by the device, based on its TPH requester capability and the Root Port's completer capability. so it's out here reading both sides of the relationship, no cap 🔥

lowkey important: the support check happens before enabling. it's not gonna half-enable something and leave you in a weird state. slay.

---

⭐ RETURN ⭐

• 0 on success 🎉
• otherwise a negative value (-errno) 😭 — so if it's not zero, something went sideways, go read that errno.

---

🌈 SEE ALSO 🌈

Kernel file ./drivers/pci/tph.c — go read the source, it's giving lore 🍓

and these besties right here:

• pcie_tph_get_st_table_loc(9)
• pcie_tph_get_cpu_st(9)
• pcie_tph_set_st_entry(9)
• pcie_disable_tph(9) — yeah, the one that turns it back off, you'll want that eventually 🙈

---

💫 sign-off 💫

this whole thing lives under ./drivers/pci, and the page is dated October 2026 — so like, future vibes, but make it kernel. periodt. 💅✨ 🌸 🦋