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From:   Benjamin Berg <benjamin@sipsolutions.net>
To:     linux-bluetooth@vger.kernel.org
Cc:     Benjamin Berg <benjamin@sipsolutions.net>
Subject: [PATCH 0/4] Cancel sync commands if a TX failure occurs
Date:   Tue,  9 Nov 2021 17:41:09 +0100
Message-Id: <20211109164113.65981-1-benjamin@sipsolutions.net>
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It was reported that userspace could hang for 10s after resuming due to
btusb hitting the internal timeout when sending the firmware.

In this case, the bluetooth dongle disappeared right after resume due to
the thinkpad_acpi rfkill being blocked. This causes the USB device to
disappear, however the bluetooth stack does not handle the
corresponding ENODEV errors and instead waits for a timeout to happen.

To avoid blocking everything for such a long time, the synchronous
command has to finish immediately after an ENODEV error occurs. This
requires further error handling, which this patchset adds by building
on top of the existing cancellation infrastructure for synchronous
commands.

Note that this just adds basic error handling in order to quickly abort
the initialization routine in case the device disappears at that time.
Additional error handling such as calling hci_reset_dev might be
sensible in some cases.

Benjamin Berg (4):
  Bluetooth: Reset more state when cancelling a sync command
  Bluetooth: Add new hci_tx_error function
  Bluetooth: hci_core: Signal TX failure if sending a frame failed
  Bluetooth: btusb: Signal URB errors as TX failure

 drivers/bluetooth/btusb.c        | 16 ++++++++++++----
 include/net/bluetooth/hci_core.h |  1 +
 net/bluetooth/hci_core.c         |  9 +++++++++
 net/bluetooth/hci_request.c      |  5 +++++
 4 files changed, 27 insertions(+), 4 deletions(-)

-- 
2.31.1