Hi Andre, * Andre Guedes <andre.guedes@xxxxxxxxxxxxx> [2012-05-30 15:08:47 -0300]: > This patch changes the default MTU value for L2CAP ATT fixed channel > to L2CAP_DEFAULT_MTU (672 octets). > > Differently from others L2CAP channels, in L2CAP ATT fixed channel > there is no MTU negotiation. The MTU value for that channel is up to > the L2CAP implementation. The only restriction in L2CAP spec is the > MTU value must not be less than 23 octets. > > At ATT protocol level (on top of L2CAP), we have the ATT_MTU which > defines the maximum size of any ATT message sent between client and > server. GATT profile defines ATT_MTU default value to 23 octets. If > a GATT based profile wants to use ATT_MTU greater than 23 octets > (e.g. HID over GATT profile), it should negotiate a new value by > executing the GATT Exchange MTU sub-procedure. > > Thus, in order to support any value of ATT_MTU negotiated at ATT > protocol level, our L2CAP implementation should have L2CAP ATT > fixed channel MTU equal or greater than ATT_MAX_MTU (512 octets). Shouldn't we define a L2CAP_LE_MAX_MTU then and set its value to 512? If we will never have anything greater than 512 octets why allow it? Gustavo -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
