doc: talk explicitly about PCI switches as an example of bridges

Signed-off-by: Brice Goglin <[email protected]>

Author: bgoglin

doc/hwloc.doxy

@@ -1064,7 +1064,7 @@ following environment variables.
   </ul>
   Domain/bus specifications should usually match entire hierarchies of buses
   behind a bridge (including primary, secondary and subordinate buses).
-  For instance, if hostbridge 0000:00 is above other bridges with buses 0000:01 to 0000:09,
+  For instance, if hostbridge 0000:00 is above other bridges/switches with buses 0000:01 to 0000:09,
   the variable should be HWLOC_PCI_LOCALITY="0000:00-09 <cpuset>".
   It supersedes the old HWLOC_PCI_0000_00_LOCALCPUS=&lt;cpuset&gt;
   which only works when hostbridges exist in the topology.
@@ -1351,7 +1351,7 @@ before loading the topology, for instance with <tt>hwloc_topology_set_io_types_f
 
 Note that I/O discovery requires significant help from the operating system.
 The pciaccess library (the development package is usually <tt>libpciaccess-devel</tt>
-or <tt>libpciaccess-dev</tt>) is needed to fully detect PCI devices and bridges.
+or <tt>libpciaccess-dev</tt>) is needed to fully detect PCI devices and bridges/switches.
 On Linux, PCI discovery may still be performed even if <tt>libpciaccess</tt> cannot
 be used. But it misses PCI device names.
 Moreover, some operating systems require privileges for probing PCI devices,
@@ -1376,7 +1376,7 @@ handle such as the <em>sda</em> drive or the <em>eth0</em> network interface.
 See \ref iodevices_osdev.
 </li><li>
 <tt>::HWLOC_OBJ_PCI_DEVICE</tt> and <tt>::HWLOC_OBJ_BRIDGE</tt> build up
-a PCI hierarchy made of bridges and devices.
+a PCI hierarchy made of bridges (that may be actually be switches) and devices.
 See \ref iodevices_pci.
 </li></ul>
 Any of these types may be filtered individually with <tt>hwloc_topology_set_type_filter()</tt>.
@@ -1499,7 +1499,7 @@ different places, but all PCI devices are below one of them
 (unless the Bridge object type is filtered-out).
 
 Each hostbridge contains one or several children, either other bridges
-(usually PCI to PCI) or PCI devices (<tt>::HWLOC_OBJ_PCI_DEVICE</tt>).
+(usually PCI to PCI switches) or PCI devices (<tt>::HWLOC_OBJ_PCI_DEVICE</tt>).
 The number of bridges between the hostbridge and a PCI device depends
 on the machine.
 

include/hwloc.h

@@ -255,7 +255,7 @@ typedef enum {
 			  */
 
   HWLOC_OBJ_BRIDGE,	/**< \brief Bridge (filtered out by default).
-			  * Any bridge that connects the host or an I/O bus,
+			  * Any bridge (or PCI switch) that connects the host or an I/O bus,
 			  * to another I/O bus.
 			  * They are not added to the topology unless I/O discovery
 			  * is enabled with hwloc_topology_set_flags().

utils/lstopo/lstopo-no-graphics.1in

@@ -218,19 +218,19 @@ These flags are passed to \fIhwloc_topology_restrict()\fR.
 Do not show any I/O device or bridge.
 This is identical to \fB\-\-filter io:none\fR.
 By default, common devices (GPUs, NICs, block devices, ...) and
-interesting bridges are shown.
+interesting bridges/switches are shown.
 .TP
 \fB\-\-no\-bridges\fB
 Do not show any I/O bridge except hostbridges.
 This is identical to \fB\-\-filter bridge:none\fR.
 By default, common devices (GPUs, NICs, block devices, ...) and
-interesting bridges are shown.
+interesting bridges/switches are shown.
 .TP
 \fB\-\-whole\-io\fB
 Show all I/O devices and bridges.
 This is identical to \fB\-\-filter io:all\fR.
 By default, only common devices (GPUs, NICs, block devices, ...) and
-interesting bridges are shown.
+interesting bridges/switches are shown.
 .TP
 \fB\-\-thissystem\fR
 Assume that the selected backend provides the topology for the
@@ -544,7 +544,7 @@ they are drawn as boxes immediately above them.
 
 .SS PCI bridges, PCI devices and OS devices
 The PCI hierarchy is not drawn as a set of included boxes but rather
-as a tree of bridges with links between them.
+as a tree of bridges (that may actually be switches) with links between them.
 The tree starts with a small square on the left for the
 hostbridge or root complex.
 It ends with PCI device boxes on the right.