xhci: Set HCD flag to defer primary roothub registration

[ Upstream commit b7a4f9b5d0e4b6dd937678c546c0b322dd1a4054 ]

Set "HCD_FLAG_DEFER_RH_REGISTER" to hcd->flags in xhci_run() to defer
registering primary roothub in usb_add_hcd() if xhci has two roothubs.
This will make sure both primary roothub and secondary roothub will be
registered along with the second HCD.
This is required for cold plugged USB devices to be detected in certain
PCIe USB cards (like Inateck USB card connected to AM64 EVM or J7200 EVM).

This patch has been added and reverted earier as it triggered a race
in usb device enumeration.
That race is now fixed in 5.16-rc3, and in stable back to 5.4
commit 6cca13de26ee ("usb: hub: Fix locking issues with address0_mutex")
commit 6ae6dc22d2d1 ("usb: hub: Fix usb enumeration issue due to address0
race")

[minor rebase change, and commit message update -Mathias]

CC: stable@vger.kernel.org # 5.4+
Suggested-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Tested-by: Chris Chiu <chris.chiu@canonical.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Link: https://lore.kernel.org/r/20220510091630.16564-3-kishon@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index a4e99f8668b38da1b59e7d99e32ab6502540f976..d76c10f9ad8070c35217db8c7c2c9c16763e1429 100644 (file)
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -693,6 +693,8 @@ int xhci_run(struct usb_hcd *hcd)
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "Finished xhci_run for USB2 roothub");
 
+       set_bit(HCD_FLAG_DEFER_RH_REGISTER, &hcd->flags);
+
        xhci_create_dbc_dev(xhci);
 
        xhci_debugfs_init(xhci);