[Bluez-devel] Slow connect time for devices

[Bluez-devel] Slow connect time for devices

[Gareth Bradley]

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Hello. I'm working on a project on a Intel XScale processor, connecting to
bluetooth heart rate monitors and headsets. Connections currently have 7
attempts to work, though leaving a debug flag on (which slows the handshake
down) gets a near-instant connection. I would like to get the connections
normal without slowing down the BT device after the connection is made.

Any normal connection, regardless of whether there's an authorization
segment, will fail (errors 104 & 110 - 'Connection timed out' and
'Connection reset by peer') 7 times before connecting. It'll usually
alternate between the two errors, and the 7 is fairly constant.

I have found that I can get the total connection time by reducing these two
variables down to 2 seconds each. It still takes seven attempts. Once the
first device is connected, any others will either be instant or have one
timeout/reset.

(rfcomm.h)
#define RFCOMM_CONN_TIMEOUT (HZ * 2)
#define RFCOMM_DISC_TIMEOUT (HZ * 2)

I later found that enabling a debug flag will give me instant connections
(how I assume things should be), because it is slowing down the process. The
flag is HCI_CORE_DEBUG in bluetooth.h, which affects the fines hci_core.c,
hci_conn.c and hci_event.c. I have isolated it to the hci_core.c file that
needs to be slowed down.

I can't, however, leave the prints on or a loop to slow it down or sleep, as
the SCO voice connection becomes unusable with them on once it is connected.

Can someone please suggest an approach to targeting and slowing down the
handshake and the not the resulting connection?

gjb.

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Re: [Bluez-devel] Slow connect time for devices

[Marcel Holtmann]

Hi Gareth,

> I'm working on a project on a Intel XScale processor, connecting to
> bluetooth heart rate monitors and headsets. Connections currently have
> 7 attempts to work, though leaving a debug flag on (which slows the
> handshake down) gets a near-instant connection. I would like to get
> the connections normal without slowing down the BT device after the
> connection is made.
> 
> Any normal connection, regardless of whether there's an authorization
> segment, will fail (errors 104 & 110 - 'Connection timed out' and
> 'Connection reset by peer') 7 times before connecting. It'll usually
> alternate between the two errors, and the 7 is fairly constant.
> 
> I have found that I can get the total connection time by reducing
> these two variables down to 2 seconds each. It still takes seven
> attempts. Once the first device is connected, any others will either
> be instant or have one timeout/reset.
> 
> (rfcomm.h)
> #define RFCOMM_CONN_TIMEOUT (HZ * 2)
> #define RFCOMM_DISC_TIMEOUT (HZ * 2)
> 
> I later found that enabling a debug flag will give me instant
> connections (how I assume things should be), because it is slowing
> down the process. The flag is HCI_CORE_DEBUG in bluetooth.h, which
> affects the fines hci_core.c, hci_conn.c and hci_event.c. I have
> isolated it to the hci_core.c file that needs to be slowed down.
> 
> I can't, however, leave the prints on or a loop to slow it down or
> sleep, as the SCO voice connection becomes unusable with them on once
> it is connected.
> 
> Can someone please suggest an approach to targeting and slowing down
> the handshake and the not the resulting connection?

this looks like a hardware limitation. What kind of dongles/chips are
you using?

Regards

Marcel




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