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[bluetooth-dev]



Hi,

good news! The USB Bluetooth driver works nearly perfect. But not with
Ericsson hardware ...

I have tried the Stack with CSR hardware, since the new BC01b Chip works
with USB. I used the following setup:
Desktop PCs with SuSE 7.0,
Kernel 2.2.18 from www.kernel.org without patches, USB Bluetooth driver from
this release,
Driver 'usb-uhci.o', since 'uhci.o' doesn't work (!),
Axis Bluetooth Stack 20010108 in usermode with CSR hardware support enabled.

I tried ftp and http without problems. The link was stable for hours. But
the data rate depends on the used hardware. Some of our computers are able
to receive only 250 kbps, one is able to receive 350 kbps (measured with
rf_send in btduser). This one has an Asus CUBX mainboard with Intel USB
hardware. The others have older Intel or Via chipsets. It seems, that the
sender hardware doesn't affect the data rate.
I reached this data rate with an RFCOMM MTU of 115 byte. With 120 byte the
data rate was lower. Maybe there is a problem, if the HCI ACL packet exceeds
128 (?) byte (RFCOMM payload + 13 byte header for RFCOMM, L2CAP and HCI). I
saw in the log file, that write_bulk_callback was called twice, if the
RFCOMM MTU was 120. Write_bulk_callback was called once with RFCOMM MTU 115.
Maybe this affects the data rate. Since the ACL Buffers of CSR Hardware are
128 byte, the HCI packets are maximal 133 byte. Unfortunately I'm not very
familiar with USB, so I don't know, what really happens.

But there is one problem. Disconnecting the USB device causes errors. The
log file shows:
"usb-uhci.c : interrupt, status 3, frame #x", x starts at 0 and increases to
2046 and restarts at 0.
I was not able to find out, what happens. I had to reboot every time after
interrupting a connection, since restarting is not able with btd with an
established physical link. Maybe someone has a solution for it.

best regards

Frank

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| Dipl.-Ing. Frank Meyering        | Phone: +49-2842-981411  |
| IMST GmbH                        | Fax:   +49-2842-981499  |
| Communication Systems & Networks |                         |
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