core: generalize comment about setting configurations with claimed interfaces

The comment about libusb_set_configuration() failing when other programs
or drivers have claimed interfaces is valid whether or not the desired
configuration is _different_ from the current one, so generalize the
statement.

While at it also make it more explicit that in case of kernel drivers,
those must be detached from _all_ interfaces before a configuration can
be set.

Finally, move the item as last as the new details also suggest
a solution for when a lightweight reset is desired but kernel drivers
have claimed other interfaces, like in the fingerprint reader example
mentioned in the same section.

Signed-off-by: Antonio Ospite <ao2@ao2.it>
Signed-off-by: Chris Dickens <christopher.a.dickens@gmail.com>

diff --git a/libusb/core.c b/libusb/core.c
index e72afcb..be658b0 100644 (file)
--- a/libusb/core.c
+++ b/libusb/core.c
@@ -223,9 +223,6 @@ struct list_head active_contexts_list;
  * -# If the device is already in the desired configuration, calling
  *    libusb_set_configuration() using the same configuration value will cause
  *    a lightweight device reset. This may not be desirable behaviour.
- * -# libusb will be unable to change configuration if the device is in
- *    another configuration and other programs or drivers have claimed
- *    interfaces under that configuration.
  * -# In the case where the desired configuration is already active, libusb
  *    may not even be able to perform a lightweight device reset. For example,
  *    take my USB keyboard with fingerprint reader: I'm interested in driving
@@ -234,6 +231,10 @@ struct list_head active_contexts_list;
  *    Because the kernel has claimed an interface, it is not even possible to
  *    perform the lightweight device reset, so libusb_set_configuration() will
  *    fail. (Luckily the device in question only has a single configuration.)
+ * -# libusb will be unable to set a configuration if other programs or
+ *    drivers have claimed interfaces. In particular, this means that kernel
+ *    drivers must be detached from all the interfaces before
+ *    libusb_set_configuration() may succeed.
  *
  * One solution to some of the above problems is to consider the currently
  * active configuration. If the configuration we want is already active, then

diff --git a/libusb/version_nano.h b/libusb/version_nano.h
index 17c3fd4..1de23d4 100644 (file)
--- a/libusb/version_nano.h
+++ b/libusb/version_nano.h
@@ -1 +1 @@
-#define LIBUSB_NANO 10971
+#define LIBUSB_NANO 10972