MFC 305034: Implement 'devctl clear driver' to undo a previous 'set driver'.

Add a new 'clear driver' command for devctl along with the accompanying
ioctl and devctl_clear_driver() library routine to reset a device to
use a wildcard devclass instead of a fixed devclass.  This can be used
to undo a previous 'set driver' command.  After the device's name has
been reset to permit wildcard names, it is reprobed so that it can
attach to newly-available (to it) device drivers.

Sponsored by:	Chelsio Communications

1 files changed, 8 insertions, 0 deletions

diff --git a/lib/libdevctl/devctl.c b/lib/libdevctl/devctl.c
index fa0e6a5..9e3b908 100644
--- a/lib/libdevctl/devctl.c
+++ b/lib/libdevctl/devctl.c
@@ -108,3 +108,11 @@ devctl_set_driver(const char *device, const char *driver, bool force)
 		req.dr_flags |= DEVF_SET_DRIVER_DETACH;
 	return (devctl_request(DEV_SET_DRIVER, &req));
 }
+
+int
+devctl_clear_driver(const char *device, bool force)
+{
+
+	return (devctl_simple_request(DEV_CLEAR_DRIVER, device, force ?
+	    DEVF_CLEAR_DRIVER_DETACH : 0));
+}