[Bug 214021] The USB devices fail to be detected during boot

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https://bugzilla.kernel.org/show_bug.cgi?id=214021

--- Comment #11 from Mathias Nyman (mathias.nyman@linux.intel.com) ---
(In reply to Alan Stern from comment #10)
> 
> Would something like the attached patch fix the problem?  It delays
> registration of the secondary root hub until after the primary hcd is
> started, just before the primary root hub is registered.

If I understood the problem correctly we would need to delay the registration
of the primary roothub until secondary hcd usb_hcd_add() reaches
hcd->driver->start()

xhci pci driver will first create and add primary hcd, then create and add
secondary hcd.

xhci_pci_probe()
  /* create AND add primary hcd in one go */
  usb_hcd_pci_probe(dev, id, &hc_driver)
  primary_hcd = dev_get_drvdata(&dev->dev)
  /* create secondary hcd */
  secondary_hcd = usb_create_shared_hcd(...,primary_hcd)
  /* add secondary hcd */
  usb_add_hcd(secondary_hcd)


If we force xhci driver to always first create both hcds, and then add them, we
could maybe do somethinh like this:


usb_hcd_add()
    ...
    if ((is_primary_hcd(hcd) && !hcd->shared_hcd) || !is_primary_hcd)
        register_roothub(primary_hcd);
    if(!is_primary_hcd(hcd))
        register_roothub(hcd);

If this makes any sense I'll turn this into real code.

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