Re: [Bluez-devel] hcid returning "Device or resource busy"?

[Bastien Nocera <hadess@hadess.net>]

On Wed, 2007-03-28 at 15:20 +0200, Marcel Holtmann wrote:
> Hi Bastien,
> 
> > > the problem is that the baseband is busy with the remote name request.
> > > It has to page the remote device for getting the name and in that case
> > > you simply can't run an inquiry. All currently available Bluetooth chips
> > > have this limitation.
> > > 
> > > Main question is why we have the remote name request just before you
> > > wanna start the inquiry. What D-Bus methods are you actually calling in
> > > what order? I think you constructed a use case that we never tested.
> > 
> > The code is fairly straight forward. See:
> > http://svn.gnome.org/viewcvs/nautilus-sendto/trunk/src/plugins/bluetooth.c?view=markup
> > 
> > The code first does a ListRemoteDevices (to list all the known, visible,
> > etc.) devices in add_known_devices_to_list(), and then runs an discovery
> > using DiscoverDevices in start_device_scanning().
> > 
> > Nothing mind blowing. I want to show all the known devices first (ie.
> > the ones in the databases), and then add the devices
> > visible/discoverable when the application is launched.
> > 
> > Is ListRemoteDevices actually doing anything on the HCI? I was under the
> > impression that it should only pull items from the disk...
> 
> I almost guessed it. The ListRemoteDevices is not the problem the
> GetRemoteName is the tricky part here. If the name is not in the cache
> it tries to resolve it and this causes the baseband page which will
> block the inquiry call.

Shouldn't it return org.bluez.Error.InProgress instead in that case?

> You can wait for the completed RemoteNameUpdated or RemoteNameFailed
> signals before actually starting the DiscoverDevices procedure. However
> in case of devices out of range this might not be a good idea.

The problem is that I don't know for which devices hcid will try to go
and fetch the names for.

Also, the doc for ListRemoteDevices should mention the fact that it
might perform remote operations, as it's not really clear from the doc
right now.

> Let me discuss this through with the others. Feel free to hop onto
> #bluez at Freenode.

Cheers

-- 
Bastien Nocera <hadess@hadess.net> 


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