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RE: [bluetooth-dev] USB data loss and question about bluetooth.c



> -----Original Message-----
> From: Edd Dumbill [mailto:edd@xxxxxxx.com] 
> Sent: Tuesday, December 11, 2001 23:22
> To: Hirotsugu Okura
> Cc: bluetooth-dev@xxxxxxx.com
> Subject: Re: [bluetooth-dev] USB data loss and question about 
> bluetooth.c
> 
> On Mon, 2001-12-10 at 00:48, Hirotsugu Okura wrote:
> > Hi all,
> > 
> > Data loss occurs
> > when I execute ping from PC1 to PC2 in the system like this.
> > 
> >   PC1: Linux RH 7.1 kernel 2.4.14 + bluetooth.c v0.12 + EricsonBTSK with USB+openBTstack 0.0.8
> >   PC2: Windows Me + PCICIA Bluetooth card (Fujitsu)
> >   These are sonnected each other with ppp over Bluetooth connection.
> > 
> > Changing datagram size of ping with -s option, if over 
> > 80-100, data loss often occures. If I use UART, it doesn't happen.
> 
> Just to confirm that I too have seen this problem occur with a USB
> dongle, and posted details to this list on 5 December (subject "apparent
> data loss with rfcomm").  I have had no follow-up, sadly, so I have no
> idea how to go about either diagnosing or solving the problem.
> 
> I guess it is a good thing that someone else has the problem too, and
> with different hardware.
> 
> -- Edd

FYI, I can tell you that we have seen the same with CSR hardware, 
so I do not think the hardware is at fault here. It is either the
OpenBT stack itself, the USB Bluetooth driver, the USB core or 
the USB driver (uhci or whatever). We use our own USB driver for
the ETRAX hardware, so I do not think it is that part of the
code since the result is the same with a standard PC.

The limit seems to be ~128 bytes. One thing I have noticed though
is that it seems that larger packets get through, but are never
responded to (at least the receive counter in Windows increase
when I send larger packets, but the send counter does not). Has
anyone tested this with something else than a Windows client?

//Peter
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