NTB(4)

📦 version 15.1, in freebsd 14.5, freebsd 15.1, nixpkgs unstable

okay bestie, this is the NTB(4) page from the Kernel Interfaces Manual, and we're folding the manual name right in here at the top. It's all about the Non-Transparent Bridge subsystem. Buckle up, it's lowkey iconic. 🦋✨

✨ NAME ✨

ntb — Non-Transparent Bridge subsystem

🛠 SYNOPSIS 🛠

To compile it into your kernel, drop these lines in your kernel configuration file:

device ntb

Or, to load it as a module at boot, drop this line in loader.conf(5):

ntb_load="YES"

These tunables can be set from loader(8):

  • hw.ntb.debug_level — Driver debug level. The default value is 0, higher means more verbose. So higher = more yapping, periodt. 🎀
  • hint.ntb_hw.X.config — Configures a set of NTB functions, separated by commas, and their resource allocation. Each function can be configured as: "[<name>][:<mw>[:<spad>[:<db>]]]", where: name is a name of the driver to attach (empty means any), mw is a number of memory windows to allocate (empty means all available), spad is a number of scratchpad registers to allocate (empty means all available), db is a number of doorbells to allocate (empty means all available). The default configuration is empty string, which means single function with all available resources, allowing any driver to attach. It's giving main character config, no cap. 💅

💅 DESCRIPTION 💅

Non-Transparent Bridges connect two computer systems with PCIe link(s), providing each of them limited access to others memory space, scratchpad registers and interrupts. The ntb subsystem uses those resources provided in generic way by hardware drivers and splits them between several functions, according to specified configuration. That's the whole vibe: PCIe bridge, limited access, resources split by config. 🫶

👀 SEE ALSO 👀

Go read these next, bestie — the supporting cast:

👑 AUTHORS 👑

The ntb subsystem was developed by Intel and originally written by Carl Delsey <carl@FreeBSD.org>. Later improvements were done by Conrad E. Meyer <cem@FreeBSD.org> and Alexander Motin <mav@FreeBSD.org>. Legends, honestly. 👑✨

This page is from Debian, dated August 29, 2019, and it's the NTB(4) manual page — mwah, slay, bye bestie! 💖✨

📦 where this page comes from