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author | Michael Brown <mcb30@ipxe.org> | 2015-05-13 14:13:09 +0100 |
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committer | Michael Brown <mcb30@ipxe.org> | 2015-05-13 14:13:09 +0100 |
commit | a2173fca45983094cfde38359132cccec51b084c (patch) | |
tree | 72d5ee239b8addfcbb67dab5a1f8e66aba22f513 /src | |
parent | 372672275e48a7f0fcd058476bd742bf950e4074 (diff) | |
download | ipxe-a2173fca45983094cfde38359132cccec51b084c.zip ipxe-a2173fca45983094cfde38359132cccec51b084c.tar.gz ipxe-a2173fca45983094cfde38359132cccec51b084c.tar.bz2 |
[usb] Do not call usb_hotplug() when registering a new hub
The action of registering a new hub can itself happen in only two
ways: either a new USB hub has been created (in which case we are
already inside a call to usb_hotplug()), or a new root hub has been
created.
In the former case, we do not need to issue a further call to
usb_hotplug(), since the hub's ports will all be marked as changed and
so will be handled after the return from register_usb_hub() anyway.
Calling usb_hotplug() within register_usb_hub() leads to a confusing
order of events, such as:
- root hub port 1 detects a change
- root hub port 2 detects a change
- usb_hotplug() is called
- root hub port 1 finds a USB hub
- usb_hotplug() is called
- this inner call to usb_hotplug() handles root hub port 2
Fix by calling usb_hotplug() only from usb_step() and from
register_usb_bus(). This avoids recursive calls to usb_hotplug() and
ensures that devices are enumerated in the order of detection.
Tested-by: Robin Smidsrød <robin@smidsrod.no>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Diffstat (limited to 'src')
-rw-r--r-- | src/drivers/bus/usb.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/src/drivers/bus/usb.c b/src/drivers/bus/usb.c index 085caf2..7574aaa 100644 --- a/src/drivers/bus/usb.c +++ b/src/drivers/bus/usb.c @@ -1779,9 +1779,6 @@ int register_usb_hub ( struct usb_hub *hub ) { */ usb_poll ( bus ); - /* Attach any devices already present */ - usb_hotplug(); - return 0; hub->driver->close ( hub ); @@ -1915,6 +1912,9 @@ int register_usb_bus ( struct usb_bus *bus ) { if ( ( rc = register_usb_hub ( bus->hub ) ) != 0 ) goto err_register_hub; + /* Attach any devices already present */ + usb_hotplug(); + return 0; unregister_usb_hub ( bus->hub ); |