NAME
ntb – Non-Transparent Bridge subsystem
SYNOPSIS
device ntb
In loader.conf(5): hw.ntb.debug_level hint.ntb_hw.%d.config ntb_load="YES"
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.
LOADER TUNABLES
The following tunables are settable from the loader(8):
- hw.ntb.debug_level
-
Driver debug level. The default value is 0, higher means more verbose.
- hint.ntb_hw.%d.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.
SEE ALSO
if_ntb(4), ntb_hw_amd(4), ntb_hw_intel(4), ntb_hw_plx(4), ntb_transport(4)
AUTHORS
The ntb subsystem was developed by Intel and originally written by Carl Delsey ⟨[email protected]⟩. Later improvements were done by Conrad E. Meyer ⟨[email protected]⟩ and Alexander Motin ⟨[email protected]⟩.