diff options
| author | Michael Brown <mcb30@ipxe.org> | 2015-05-06 16:38:28 +0100 |
|---|---|---|
| committer | Michael Brown <mcb30@ipxe.org> | 2015-05-08 14:57:14 +0100 |
| commit | f6604627ff71d42bb63a3d81c2986a9d296d55cb (patch) | |
| tree | 8eb038959b4e3429c4c15e9a1a7a5bd73e68c2b2 /src/drivers/usb/usbhub.c | |
| parent | b88ab14ba38d0eb2123975ed78c8eb04ba13cf72 (diff) | |
| download | ipxe-f6604627ff71d42bb63a3d81c2986a9d296d55cb.tar.gz | |
[usb] Detect missed disconnections
The USB core will currently fail to detect disconnections if a new
device has attached by the time the port is examined in
usb_hotplug().
Fix by recording the fact that a disconnection has taken place
whenever the "connection status changed" (CSC) bit is observed to be
set. (Whether the change represents a disconnection or a
reconnection, it indicates that the port has experienced some time of
being disconnected.)
Note that the time at which a disconnection can be detected varies by
hub type. In particular: root hubs can observe the CSC bit when
polling, and so will record the disconnection before calling
usb_port_changed(), but USB hubs read the port status (and hence the
CSC bit) only during the call to hub_speed(), long after the call to
usb_port_changed().
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Diffstat (limited to 'src/drivers/usb/usbhub.c')
| -rw-r--r-- | src/drivers/usb/usbhub.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/src/drivers/usb/usbhub.c b/src/drivers/usb/usbhub.c index 6d0cdba45..8b5fa9c4d 100644 --- a/src/drivers/usb/usbhub.c +++ b/src/drivers/usb/usbhub.c @@ -331,6 +331,9 @@ static int hub_speed ( struct usb_hub *hub, struct usb_port *port ) { port->speed = USB_SPEED_NONE; } + /* Record disconnections */ + port->disconnected |= ( changed & ( 1 << USB_HUB_PORT_CONNECTION ) ); + /* Clear port status change bits */ if ( ( rc = hub_clear_changes ( hubdev, port->address, changed ) ) != 0) return rc; |