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Make default RFCOMM session MTU match default L2CAP MTU.

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This is just a workaround for a know problem with Motorola E1000
phone. Something is wrong with the configuration of L2CAP/RFCOMM
channel. Even though we set L2CAP MTU to 132 bytes (default RFCOMM
MTU 127 + 5 bytes RFCOMM frame header) and the phone accepts it,
the phone still sends oversized L2CAP packets. It appears that the
phone wants to use bigger (667 bytes) RFCOMM frames, but it does
not segment them according to the configured L2CAP MTU. The 667
bytes RFCOMM frame size corresponds to the default L2CAP MTU of
672 bytes (667 + 5 bytes RFCOMM frame header).

This problem only appears if connection was initiated from the
phone. I'm not sure who is at fault here, so for now just put
workaround in place. Quick look at the spec did not reveal any
anwser.

Tested by:	Jes < jjess at freebsd dot polarhome dot com >
MFC after:	3 days
This commit is contained in:
Maksim Yevmenkin 2005-01-11 01:39:53 +00:00
parent d6c7f7a122
commit 980b8b89eb
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=140027
1 changed files with 3 additions and 3 deletions
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6
sys/netgraph/bluetooth/include/ng_btsocket_rfcomm.h
View File

@ -42,7 +42,7 @@
/* XXX FIXME this does not belong here */
#define RFCOMM_DEFAULT_MTU 127
#define RFCOMM_DEFAULT_MTU 667
#define RFCOMM_MAX_MTU 1024
#define RFCOMM_DEFAULT_CREDITS 7
@ -218,9 +218,9 @@ struct rfcomm_mcc_pn
*****************************************************************************/
#define NG_BTSOCKET_RFCOMM_SENDSPACE \
(RFCOMM_MAX_CREDITS * RFCOMM_DEFAULT_MTU * 10)
(RFCOMM_MAX_CREDITS * RFCOMM_DEFAULT_MTU * 2)
#define NG_BTSOCKET_RFCOMM_RECVSPACE \
(RFCOMM_MAX_CREDITS * RFCOMM_DEFAULT_MTU * 10)
(RFCOMM_MAX_CREDITS * RFCOMM_DEFAULT_MTU * 2)
/*
* Bluetooth RFCOMM session. One L2CAP connection == one RFCOMM session