On Thu, 8 Nov 2012, Pratyush Anand wrote: > USB specs says that if an over-current is detected then a hub must switch off > all affected port, wait to cool down and then switch on. > > There are few controllers, which does not follow it, and expects software > to switch off the port power. Can you give any examples? > This patch will add workaround for such controllers. > > I think it will not affect others, even if HW switch off the port power. > > Signed-off-by: Pratyush Anand <pratyush.anand@xxxxxx> > --- > drivers/usb/core/hub.c | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c > index 1af04bd..6674344 100644 > --- a/drivers/usb/core/hub.c > +++ b/drivers/usb/core/hub.c > @@ -4531,6 +4531,9 @@ static void hub_events(void) > > dev_dbg(hub_dev, "over-current change on port " > "%d\n", i); > + if (hdev == hdev->bus->root_hub) Normally we test for root hubs by doing: if (!hdev->parent) You also might want to avoid turning off the power feature if it is already off: if (!hdev->parent && (portstatus & USB_PORT_STAT_POWER)) > + clear_port_feature(hdev, i, > + USB_PORT_FEAT_POWER); > clear_port_feature(hdev, i, > USB_PORT_FEAT_C_OVER_CURRENT); > msleep(100); /* Cool down */ 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
