>From: Alan Stern [mailto:[EMAIL PROTECTED] >On Mon, 21 May 2007, David Brownell wrote: >> On Monday 21 May 2007, Vikram Pandita wrote: >> > --- >> > diff -purN -X ./dontdiff a/drivers/usb/core/hub.c >> > b/drivers/usb/core/hub.c >> > --- a/drivers/usb/core/hub.c 2007-05-13 14:24:43.000000000 +0530 >> > +++ b/drivers/usb/core/hub.c 2007-05-21 13:19:07.000000000 +0530 >> > @@ -2571,7 +2571,7 @@ loop: >> > ep0_reinit(udev); >> > release_address(udev); >> > usb_put_dev(udev); >> > - if (status == -ENOTCONN) >> > + if ((status == -ENOTCONN) || (status == -ENODEV)) >> > break; >> > } > >This is wrong. -ENOTCONN means what it says, that nothing is connected >to the port. So when it occurs we really do want to break out of the >loop. > >On the other hand, -ENODEV means that there is a device but it doesn't >match our preconceptions (maybe its speed has somehow changed or some >other aspect is different). Since there still is a device connected to >the port, we don't want to break out of the loop. > >Did you notice any particular example where the port was unconnected >and the code still tried to enumerate three times?
Yes. This is to fix the OTG HNP case. In OTG enabled environment when the b-device attached is not supported by host (is_targeted() returns Zero), the host suspends to give chance to device to become b-host. If this fix is not in place, then the host tries to enumerate the attached device SET_CONFIG_TRIES times which is not required. Following is the snippet of the code already in place that does the HNP and returns the error code to stop re-enumerations and the proposed patch checks for this error code: if (!is_targeted(udev)) { /* Maybe it can talk to us, though we can't talk to it. * (Includes HNP test device.) */ if (udev->bus->b_hnp_enable || udev->bus->is_b_host) { err = __usb_port_suspend(udev, udev->bus->otg_port); if (err < 0) dev_dbg(&udev->dev, "HNP fail, %d\n", err); } err = -ENODEV; goto fail; } > Vikram Pandita ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel