[RFC] Interface to set LE connection parameters

[Ville Tervo <ville.tervo@nokia.com>]

Hi,

LE profiles have different requirements for connection parameters. Mainly
trying to balance between power consumption and latencies. Probably more will
factors will be in future.

Currently I have plan to introduce new l2cap socket option which can be used
before connection creation to set inital settings and also change settings
while having a connection.

Since there is no equivalents in EDR/BR connection I'm planning to make then
apply only LE connection.


Other question which parameters should be exposed to user space? Connection
creation and connection update have these common parameters. Connection
creation has in addition some other parameters also but they should be handled
in some other way.

	__le16   conn_interval_min;
	__le16   conn_interval_max;
	__le16   conn_latency;
	__le16   supervision_timeout;
	__le16   min_ce_len;
	__le16   max_ce_len;

So far I have had two ideas. The first is to simply expose all these fields
with sock_opt. In that way profiles would be able to define their requirements
also in future without any sock opt changes.

Second is to define BT_LE_LOW_LAT for low latency connection requirements and
BT_LE_LOW_POWER connection where the latency is not an issue. It would make
usage of this sock opt interface simplier. OTOH the only user should be
bluetoothd so it doesn't need to be as simple as possible.


Comments please.

-- 
Ville