It am using QN9021 SoC working in controller mode (BLE Bluetooth core specification v4.0). It supports some standard HCI commands as well as some vendor specific commands. I am trying to attach it in my ubuntu laptop.

The command that i have used is hciattach.

hciattach -s 9600 /dev/ttyUSBx any 9600 noflow nosleep 

The hcidump shows while executing sudo hciconfig hci1 up.

HCI sniffer - Bluetooth packet analyzer ver 5.37
device: hci1 snap_len: 1500 filter: 0xffffffffffffffff
> HCI Event: Command Complete (0x0e) plen 12
    Read Local Supported Features (0x04|0x0003) ncmd 11
    status 0x00
    Features: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
> HCI Event: Command Complete (0x0e) plen 12
    Read Local Version Information (0x04|0x0001) ncmd 11
    status 0x00
    HCI Version: 4.0 (0x6) HCI Revision: 0x400
    LMP Version: 4.0 (0x6) LMP Subversion: 0x400
    Manufacturer: Quintic Corp. (142)
> HCI Event: Command Complete (0x0e) plen 10
    Read BD ADDR (0x04|0x0009) ncmd 11
    status 0x00 bdaddr 08:7C:BE:3E:34:BB
> HCI Event: Command Complete (0x0e) plen 11
    Read Buffer Size (0x04|0x0005) ncmd 11
    status 0x00
    ACL MTU 0:0 SCO MTU 0:0
> HCI Event: Command Complete (0x0e) plen 4
    Read Class of Device (0x03|0x0023) ncmd 11
    status 0x01 class 0x000000
    Error: Unknown HCI Command

The hciconfig command shows:

hci1:   Type: BR/EDR  Bus: UART
    BD Address: 08:7C:BE:3E:34:BB  ACL MTU: 0:0  SCO MTU: 0:0
    RX bytes:192 acl:0 sco:0 events:15 errors:0
    TX bytes:60 acl:0 sco:0 commands:15 errors:0

hci0:   Type: BR/EDR  Bus: USB
    BD Address: C4:8E:8F:66:3B:0E  ACL MTU: 820:8  SCO MTU: 255:16
    RX bytes:2457 acl:0 sco:0 events:196 errors:0
    TX bytes:24646 acl:0 sco:0 commands:196 errors:0

I would like to know how to prevent the kernel or some bluetooth kernel module to send non-supported HCI commands. Do i need to patch linux kernel source code or write a module for my SoC.

Note:- Changing the SoC or writing firmware for it to support all necessary commands is not possible for this project.


I know the list of HCIcommand supported by my SoC. I am thinking of creating a module to tell the kernel and daemons running to send only supported commands to the SoC. I have a look at linux kernel source (specifically at this hci_core.c). I think modifying it may solve the problem after going through this link. In this link, some developer has provided a patch to support a bluetooth dongle. The patch prevents the hci_core.c file to send a specific HCI command to a dongle of a particular manufacturer.

All i want is suggestion to resolve this problem. Do i need to modify the linux kernel or write a module for my SoC?

NOTE:- The application will run on openwrt linux.

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