4.20-stable review patch. If anyone has any objections, please let me know.
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From: Karoly Pados pados@pados.hu
commit a8eda9fa1bd84065b75bfa81bf675a7af9055478 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: ba93cc7da896 ("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
--- drivers/usb/serial/ftdi_sio.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)
--- a/drivers/usb/serial/ftdi_sio.c +++ b/drivers/usb/serial/ftdi_sio.c @@ -1783,6 +1783,10 @@ static int ftdi_set_bitmode(struct usb_s int result; u16 val;
+ result = usb_autopm_get_interface(serial->interface); + if (result) + return result; + val = (mode << 8) | (priv->gpio_output << 4) | priv->gpio_value; result = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0), @@ -1795,6 +1799,8 @@ static int ftdi_set_bitmode(struct usb_s val, result); }
+ usb_autopm_put_interface(serial->interface); + return result; }
@@ -1846,9 +1852,15 @@ static int ftdi_read_cbus_pins(struct us unsigned char *buf; int result;
+ result = usb_autopm_get_interface(serial->interface); + if (result) + return result; + buf = kmalloc(1, GFP_KERNEL); - if (!buf) + if (!buf) { + usb_autopm_put_interface(serial->interface); return -ENOMEM; + }
result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0), @@ -1863,6 +1875,7 @@ static int ftdi_read_cbus_pins(struct us }
kfree(buf); + usb_autopm_put_interface(serial->interface);
return result; }