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/[email protected]
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/[email protected]/
[2] -> https://lore.kernel.org/linux-usb/[email protected]
[3] -> https://lore.kernel.org/r/[email protected]
[4] -> http://lore.kernel.org/r/[email protected]
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