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RE: [bluetooth-dev] RE: confused on HCI data packets



if you are writing your own thin hci layer, you don't need an l2cap header.
l2cap would just make use of an hci connection, and therefore, is completely
transparent to the hci layer.

i have also written a somewhat complete hci layer with which i open a
connection directly (using an ioctl wrapper) and buffer data to be
transmitted via ACL packets. i used CSR hardware, so i don't know anything
about the ericsson. if they 'interpret' the bluetooth spec as loosely as
CSR, there could be any variey of reasons why you are experiencing troubles,
but I think they must have done a pretty good job because there are more
than one open source stack that uses the ericsson edk.

can i assume that you are able to configure the device, and that you receive
the corresponding event messages? do you handle all error codes, or at
least, do you make note of errors which you don't specifically handle?

if you were to send me a sample ACL packet, i could determine whether it was
constucted properly. there really isn't much to it, though... off the top of
my head: 1 byte as ACL packet designator, 2 bytes for connection handle and
associated flags, 2 bytes for length, and data.

can you run your driver in user mode? you could use gdb to trace your
execution to make sure you're really doing what you think. are you sure that
the data is getting from user space to kernel space? what kind of debugging
do you have set up?

are you using multiple processes? if so, how do you communicate between
them? sometimes IPC can be a stumbling block.

that's all i can think of without more information.

Dave.


> -----Original Message-----
> From: Sami Kibria [mailto:skibria@xxxxxxx.ca]
> Sent: Thursday, May 17, 2001 12:36 PM
> To: Gathright, Dave
> Cc: Bluetooth-Dev
> Subject: RE: [bluetooth-dev] RE: confused on HCI data packets
> 
> 
> hey dave...how are you?
> 
> okay...let me give you some info on my driver...i am not really using
> axis' bluetooth driver but i am writing my own for some very specific
> research projects here at trlabs (this is where i work)...so 
> that is why i
> am asking very specific questions in regards to how to send 
> and see acl
> data packets...
> 
> so my progress has been okay (i am a little behind in terms of my
> development) because i do get a connection complete event 
> indicating that
> i have a "physical" connection between my two devices...but 
> not it comes
> down to how to get my packet from host a to host b...
> 
> i am using the ericsson hardware (got if from comtec sigma in 
> sweden), and
> like i said before my own "stack", actaully it is a really 
> thin HCI driver
> that i need...
> 
> so i really need to know what has to go into the header...i 
> was told that
> the header should look something like:
> 
> -------------
> |  ACL_PKT  |
> -------------
> |  hci data |
> |  header   |
> -------------
> | L2CAP     |
> | header    |
> -------------
> | data part |
> |     .     |
> |     .     |
> |     .     |
> -------------
> 
> but currently i am missing the l2cap header, because it 
> really doesn't say
> it needs it anywhere...so what do you think???
> 
> thanks
> 
> 
> 
> --------------------------------------------------------------------
> Sami Kibria
> Researcher
> TRLabs - Winnipeg, Manitoba. CANADA
> email: skibria@xxxxxxx.ca
> --------------------------------------------------------------------
>    __   _
>   / /  (_)__  __ ____  __
>  / /__/ / _ \/ // /\ \/ /  . . .  t h e   c h o i c e   o f   a
> /____/_/_//_/\_,_/ /_/\_\              G N U   g e n e r a t i o n
> 
> --------------------------------------------------------------------
> 
> On Thu, 17 May 2001, Gathright, Dave wrote:
> 
> > which hardware and which stack are you using? have you had 
> any positive
> > experiences, e.g., talking to the device in user mode, or ???
> > 
> 
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