On Tue, 10 Jan 2012, Sarah Sharp wrote: > When a SuperSpeed device is plugged into a high speed hub or an EHCI > port, it will show up as a high speed device with a BCD of 0x0201 or > 0x210 and it will contain a SuperSpeed Capabilities BOS descriptor. If > we see such a high speed device, warn the user that they should plug > their device into a USB 3.0 hub or xHCI root port. Only warn the user > if there is at least one SuperSpeed roothub available. > > We could attempt to fetch BOS descriptors for low or full speed devices, > in case the user plugs in a USB 3.0 device into an OHCI or UHCI-only > port, but it's possible those devices will choke on the request and fail > to be enumerated. Keep the current behavior of only asking for BOS > descriptors for devices that advertise a bcdUSB of 0x0201 and above. > > Signed-off-by: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx> > Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> > Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> > --- > drivers/usb/core/hub.c | 18 ++++++++++++++++++ > 1 files changed, 18 insertions(+), 0 deletions(-) > > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c > index 79d339e..1224a69 100644 > --- a/drivers/usb/core/hub.c > +++ b/drivers/usb/core/hub.c > @@ -3361,6 +3375,10 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1, > && udev->speed == USB_SPEED_FULL > && highspeed_hubs != 0) > check_highspeed (hub, udev, port1); > + if (le16_to_cpu(udev->descriptor.bcdUSB) >= 0x0201 && > + udev->speed == USB_SPEED_HIGH && > + superspeed_hubs != 0) > + check_superspeed(hub, udev, port1); I'm probably just repeating Sebastian's advice, but... There's no reason to check bcdUSB. All you care about is whether or not there is a BOS descriptor with an SS capability, and check_superspeed() looks for that. Also, for thoroughness the test should be udev->speed < USB_SPEED_SUPER. (The highspeed check code ought to have done the same sort of thing.) In theory, somebody could plug a USB-3.0 device into a USB-1.1 controller. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
