ntb4
Non-transparent bridge subsystem
Usage
device ntb
In loader.conf(5): hw.ntb.debug_level hint.ntb_hw.%d.config ntb_load="YES"
Overview
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.
Releases
30 releases since FreeBSD 10.0-RELEASE; the text changed 17 times.