USB: serial: ftdi_sio: fix GPIO not working in autosuspend

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commit a8eda9fa1b upstream.

There is a bug in the current GPIO code for ftdi_sio: it failed to take USB
autosuspend into account. If the device is in autosuspend, calls to
usb_control_msg() fail with -EHOSTUNREACH. Because the standard value for
autosuspend timeout is usually 2-5 seconds, this made it almost impossible
to use the GPIOs on machines that have USB autosuspend enabled. This patch
fixes the issue by acquiring a PM lock on the device for the duration of
the USB transfers. Tested on an FT231X device.

Signed-off-by: Karoly Pados <pados@pados.hu>
[ johan: simplify code somewhat ]
Fixes: ba93cc7da8 ("USB: serial: ftdi_sio: implement GPIO support for FT-X devices")
Cc: stable <stable@vger.kernel.org>	# 4.20
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Karoly Pados 2019-01-14 13:30:03 +01:00 • committed by Greg Kroah-Hartman

parent 8f720afc41

commit d99be59504

1 changed files with 14 additions and 1 deletions

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drivers/usb/serial/ftdi_sio.c

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