Greetings Marcel,
I have a small, wearable computer, battery powered, of course. The
X-scale processor is connected to the BT radio through a serial port and
is the master in a small network of BT devices. All this works very
well. This is running Linux 2.6 with the latest patches.
During idle periods, to save power, I want to suspend the main
microprocessor. The BT radio is powered from a separate circuit. For
now, before I suspend the micro, I close all the connections, and
perform a "bluetooth stop". When the micro wakes up, the micro does a
"bluetooth start" and then reestablishes the connections to the
peripheral devices. This does work, but it takes some time. I would like
to have the BT network recover as quickly as possible.
Is it possible to instruct the BT radio to autonomously maintain the
established connections, even though the microprocessor has been
suspended ? So that when the main processor wakes up, the BT network is
still there. I don't know how much of the connection "keep alive"
function is performed by the Bluez stack.
Thank you, as usual for all your help.
Best Regards,
Rich
----------------------------
Richard B. Williams
Vitronics, Inc.
An MTC Technologies Company
3 Corbett Way
Eatontown, NJ 07724-2262
732-389-0244 x29
[email protected]
Hi Richard,
just some crude thoughts about this:
What happens if one of the remote devices wants to send some data to the
PDA ?? Or can you make sure that this will not happen ?? If it can happen
you need some sort of wakeup on your host. If the host can wake up on
serial line activity this is fine, but as far as I remember this is not
possible with an X-scale.
If you are sure that the above will not cause you problems you could put
all active connections into park mode, which will allow the BT chip to
save a lot of power. However, you have to remember the state of each
active connection to unpark it once your host wakes up. Because you have
to remeber te connections states a bluetooth stop / start is not an
option. You have to add (I don't know if there already is something, but
from Marcels answer I think it is not) power management at least to the
HCI layer which parks the slaves if you enter low power state and unparks them
when you come back.
Good luck !!!
Peter
On Thu, 10 Feb 2005, Williams, Richard wrote:
> Greetings Marcel,
>
> I have a small, wearable computer, battery powered, of course. The
> X-scale processor is connected to the BT radio through a serial port and
> is the master in a small network of BT devices. All this works very
> well. This is running Linux 2.6 with the latest patches.
>
> During idle periods, to save power, I want to suspend the main
> microprocessor. The BT radio is powered from a separate circuit. For
> now, before I suspend the micro, I close all the connections, and
> perform a "bluetooth stop". When the micro wakes up, the micro does a
> "bluetooth start" and then reestablishes the connections to the
> peripheral devices. This does work, but it takes some time. I would like
> to have the BT network recover as quickly as possible.
>
> Is it possible to instruct the BT radio to autonomously maintain the
> established connections, even though the microprocessor has been
> suspended ? So that when the main processor wakes up, the BT network is
> still there. I don't know how much of the connection "keep alive"
> function is performed by the Bluez stack.
>
> Thank you, as usual for all your help.
>
> Best Regards,
>
> Rich
>
> ----------------------------
> Richard B. Williams
> Vitronics, Inc.
> An MTC Technologies Company
> 3 Corbett Way
> Eatontown, NJ 07724-2262
> 732-389-0244 x29
> [email protected]
>
>
>
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| G&W Instruments GmbH fax: +49 30 46776419 |
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Hi Richard,
> I have a small, wearable computer, battery powered, of course. The
> X-scale processor is connected to the BT radio through a serial port
> and is the master in a small network of BT devices. All this works
> very well. This is running Linux 2.6 with the latest patches.
>
> During idle periods, to save power, I want to suspend the main
> microprocessor. The BT radio is powered from a separate circuit. For
> now, before I suspend the micro, I close all the connections, and
> perform a "bluetooth stop". When the micro wakes up, the micro does a
> "bluetooth start" and then reestablishes the connections to the
> peripheral devices. This does work, but it takes some time. I would
> like to have the BT network recover as quickly as possible.
>
> Is it possible to instruct the BT radio to autonomously maintain the
> established connections, even though the microprocessor has been
> suspended ? So that when the main processor wakes up, the BT network
> is still there. I don't know how much of the connection "keep alive"
> function is performed by the Bluez stack.
not that I know and there is no keep alive in the BlueZ stack. Actually
we don't support idle disconnect and even not automatic sniff mode. The
latter one is on my todo list.
Regards
Marcel
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