svn commit: r327036 - head/share/man/man4

[Warner Losh]

Author: imp
Date: Wed Dec 20 19:14:11 2017
New Revision: 327036
URL: https://svnweb.freebsd.org/changeset/base/327036

Log:
  Document new pci device hints wiring.
  
  Sponsored by: Netflix
  Differential Revision: https://reviews.freebsd.org/D13546

Modified:
  head/share/man/man4/pci.4

Modified: head/share/man/man4/pci.4
==============================================================================
--- head/share/man/man4/pci.4	Wed Dec 20 19:14:05 2017	(r327035)
+++ head/share/man/man4/pci.4	Wed Dec 20 19:14:11 2017	(r327036)
@@ -492,6 +492,59 @@ The value of the tunable is the raw IRQ value to use f
 pin identified by the tunable name.
 Mapping of IRQ values to platform interrupt sources is machine dependent.
 .El
+.Sh DEVICE WIRING
+You can wire the device unit at a given location with device.hints.
+Entries of the form
+.Va hints.<name>.<unit>.at="pci<B>:<S>:<F>"
+or
+.Va hints.<name>.<unit>.at="pci<D>:<B>:<S>:<F>"
+will force the driver
+.Va name
+to probe and attach at unit
+.Va unit
+for any PCI device found to match the specification, where:
+.Bl -tag -width -indent
+.It <D>
+The domain
+.Pq or segment
+of the PCI device in decimal.
+Defaults to 0 if unspecified
+.It <B>
+The bus address of the PCI device in decimal.
+.It <S>
+The slot of the PCI device in decimal.
+.It <F>
+The function of the PCI device in decimal.
+.El
+.Pp
+The code to do the matching requires an exact string match.
+Do not specify the angle brackets
+.Pq < >
+in the hints file.
+Wiring multiple devices to the same
+.Va name
+and
+.Va unit
+produces undefined results.
+.Ss Examples
+Given the following lines in
+.Pa /boot/device.hints :
+.Cd hint.nvme.3.at="pci6:0:0"
+.Cd hint.igb.8.at="pci14:0:0"
+If there is a device that supports
+.Xr igb 4
+at PCI bus 14 slot 0 function 0,
+then it will be assigned igb8 for probe and attach.
+Likewise, if there is an
+.Xr nvme 4
+card at PCI bus 6 slot 0 function 0,
+then it will be assigned nvme3 for probe and attach.
+If another type of card is in either of these locations, the name and
+unit of that card will be the default names and will be unaffected by
+these hints.
+If other igb or nvme cards are located elsewhere, they will be
+assigned their unit numbers sequentially, skipping the unit numbers
+that have 'at' hints.
 .Sh FILES
 .Bl -tag -width /dev/pci -compact
 .It Pa /dev/pci