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From:   Kishon Vijay Abraham I <kishon@ti.com>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Mathias Nyman <mathias.nyman@intel.com>,
        Alan Stern <stern@rowland.harvard.edu>
CC:     Kishon Vijay Abraham I <kishon@ti.com>,
        <linux-usb@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: [RESEND PATCH v2 0/2] Fix cold plugged USB device on certain PCIe USB cards
Date:   Tue, 10 May 2022 14:46:28 +0530
Message-ID: <20220510091630.16564-1-kishon@ti.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

Cold plugged USB device was not detected on certain PCIe USB cards
(like Inateck card connected to AM64 EVM or connected to J7200 EVM).

Re-plugging the USB device always gets it enumerated.

This issue was discussed in
https://lore.kernel.org/r/772e4001-178e-4918-032c-6e625bdded24@ti.com
and
https://bugzilla.kernel.org/show_bug.cgi?id=214021

So the suggested solution is to register both root hubs along with the
second hcd for xhci.

RFC Patch series can be found at [1]
v1 Patch series can be found at [3]
v2 PATCH series can be found at [4]

Changes from v2:
1) No Change (rebased to latest mainline kernel). V2 was reverted from
mainline after it triggered a race in USB enumeration. Posting the patch
(as attached in https://bugzilla.kernel.org/attachment.cgi?id=300800 after
validating this fixes the issue using TI AM654 IDK EVM).

Changes from RFC:
1) Mathias identified potential issues with the RFC patch [2] and suggested
   the solution to use HCD flags. This series implements it.

Changes from v1:
1) Fixed code comments pointed out by Alan Stern
2) Renamed the HCD flag variable to "HCD_FLAG_DEFER_RH_REGISTER" from
   "HCD_FLAG_DEFER_PRI_RH_REGISTER"

[1] -> https://lore.kernel.org/linux-usb/20210824105302.25382-1-kishon@ti.com/
[2] -> https://lore.kernel.org/linux-usb/06693934-28f2-d59e-b004-62cabd3f9e8e@linux.intel.com
[3] -> https://lore.kernel.org/r/20210825105132.10420-1-kishon@ti.com
[4] -> http://lore.kernel.org/r/20210826111426.751-1-kishon@ti.com

Kishon Vijay Abraham I (2):
  usb: core: hcd: Add support for deferring roothub registration
  xhci: Set HCD flag to defer primary roothub registration

 drivers/usb/core/hcd.c  | 29 +++++++++++++++++++++++------
 drivers/usb/host/xhci.c |  2 ++
 include/linux/usb/hcd.h |  2 ++
 3 files changed, 27 insertions(+), 6 deletions(-)

-- 
2.17.1