Re: IdleTimeout behavior for Sony PS3 remote in Bluez 5

Hi Luiz,

Luiz Augusto von Dentz [luiz.dentz@gmail.com] wrote:

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I have set IdleTimeout=1 in /etc/bluetooth/input.conf.  My
understanding is that this should disconnect from the remote after one
minute of inactivity.  What I find, however, is that after exactly one
minute, the *input device* disappears (i.e. no longer listed
in /proc/bus/input/devices) but the connection to the remote remains
active.  Ten or twenty minutes later, it still shows as "Connected" in
bluetoothctl or hcitool con:

Connections:
        > ACL 00:21:4F:48:D1:D2 handle 256 state 1 lm MASTER

Yes, IdleTimeout should disconnect the device in case there is nothing
else connect (no other sockets except HID), but note that IdleTimeout
currently does not work with UserspaceHID.

[...]

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Looks like the sockets are not really closed then thus keeping the ACL
active which is probably a bug, does bluetoothd logs indicate a
disconnection or it is just the input device that disappears?

Thanks, it's good to know that this is the expected behavior.  But what do
you mean by "userspace HID"?  I am only using evdev (via Python).

Tonight I will run the experiment again with "bluetoothd -n -d" and let you
know what happens.  I already see some errors about the sap driver
initialization failing, but that may be unrelated.

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This depend from device to device, usually this policy is done by the
device itself since it knows better when it should be disconnected so
usually IdleTimeout is used only for *broken devices that don't
implement any policy to conserve their own batteries most likely
because windows driver have these policies built in, perhaps we also
should have this kind of policy in the input driver but I don't know
if there is any support to disconnect a device after a period of
inactivity.

Apparently the following lines were removed in the commit
5205185d461d5902325e457ca80bd421127b7308:

-       /* Wakeup user-space polling for socket errors */
-       session->intr_sock->sk->sk_err = EUNATCH;
-       session->ctrl_sock->sk->sk_err = EUNATCH;

Without this I doubt the userspace will realize that it should release
the sockets which means this as been broken for over 2 years and
probably nobody realized up until today, it is probably only useful
when IdleTimeout is set since it is the only case where the module
itself device to remove the device and disconnect.

The PS3 remote is definitely one of those broken devices.  During bluez 4.xx
there were a set of unofficial patches maintained at kitlaan.twinaxis.com
(now defunct).  Not a long-term tenable solution, although I was never clear
on whether all his changes were actually necessary in later bluez versions. 
It seems like IdleTimeout should be enough, if it can be made to disconnect. 
Reconnect and evdev init works just fine on the next keypress.

Mark