rfcomm_pppd fails (T40p and Nokia 7650)

[Maksim Yevmenkin]

Hello Peter,

[...]

> > this is local device tells that it has failed to create baseband
> connection
> > to the remote with BD_ADDR 00:02:EE:73:89:0B (link type ACL/no
> encryption).
> > the status code is 0x04 - Page Timeout. 
> > 
> > bottom line: the local device has failed to create baseband connection to
> the
> > phone. when device is idle the radio is only turned on for a brief periods
> of
> > time to scan for page attempts (from remote devices). it is possible for
> the
> > device to miss such page attempt and thus incoming connection may fail. i
> > think
> > that is what might be going on. 
> 
> Sounds likely. In general Bluetooth seems a bit half-flaky on phones,
> even when doing phone-to-phone stuff. Perhaps this is a just a more
> explicit report on the same problem that causes failures in general. 
> 
> > could you please put your phone into "discoverable" mode, run 
> > "hccontrol -n <dev>hci inquiry" and send me the output?
> 
> The only relevant settings on the 7650 seems to be the disable/enable
> flag for bluetooth and wether it's "visible" or "hidden" to other
> devices. I assume "visible" means it's discoverable; just using
> different terminoligy.

right :) "visible" means "discoverable", i.e. the device will answer
to inquiry from the other devices.

> If so, I have it set to discoverable mode at all times (when BT is
> enabled).
> 
> Here's the output of a successful inquiry:
> 
> thunderbolt# hccontrol -n ubt0hci inquiry
> Inquiry result, num_responses=1
> Inquiry result #0
>         BD_ADDR: 00:02:ee:73:89:0b
>         Page Scan Rep. Mode: 0x1
>         Page Scan Period Mode: 00
>         Page Scan Mode: 00
>         Class: 50:22:04
>         Clock offset: 0x984
> Inquiry complete. Status: No error [00]
> thunderbolt# 

well, it looks normal to me with one exception - Page Scan Period Mode is
set to 0x1 - P1 mode. the default settings for a device is usually 0x00 - P0
mode. perhaps this makes difference? unfortunately current hccontrol(8) tool
does not support Read/Write_Page_Scan_Period_Mode command. i will add support
for these commands in the next release, so you can try and set P1 Page Scan 
Period Mode on the device attached to your PC. 

> At the moment all attemps are successful, though I am relatively sure
> that I've seen it fail sometimes (but then the output isn't very
> interesting so).

did you ever get a different hcidump from the failed sessions? or it always
fails at create baseband connection phase?

> > of course i'm interesting in improving the code :) btw, do you have the
> same
> > problems on other systems (Windows or Linux)?
> 
> I don't have Linux on this machine, but I can ask my friend if he's
> experiencing the same problems (same phone but different Bluetooth
> card).
> 
> As for Winodws, I'll have a go trying to cause random failures the next
> time I'm in it.

thank you very much for your time and help,
max

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