Fake CSR 4.0 Bluetooth Dongle with error Set Event Filter(Invalid HCI Command Parameters) after kernel patch

I've got a fake dongle BT 4.0 from china and try the procedure from this thread: Bluetooth dongle problem

Distributor ID: Ubuntu
Description: Ubuntu 20.04.1 LTS
Release: 20.04
Codename: focal
Device: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode) bcdDevice: 88.91 Kernel: 5.10.3-051003-generic
usb-devices | awk '/0a12/' RS=
T: Bus=02 Lev=02 Prnt=02 Port=01 Cnt=01 Dev#= 3 Spd=12 MxCh= 0
D: Ver= 2.00 Cls=e0(wlcon) Sub=01 Prot=01 MxPS=64 #Cfgs= 1
P: Vendor=0a12 ProdID=0001 Rev=88.91
S: Product=BT DONGLE10
C: #Ifs= 2 Cfg#= 1 Atr=80 MxPwr=100mA
I: If#=0x0 Alt= 0 #EPs= 3 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb
I: If#=0x1 Alt= 0 #EPs= 2 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb

But even after patch, I'm getting the error below via hcidump:

HCI Event: Command Complete (0x0e) plen 4 Set Event Filter (0x03|0x0005) ncmd 1 status 0x12 Error: Invalid HCI Command Parameters

Check it:

"Same device and same issue on Pi Zero. "Changing the #define lmp_bredr_capable(dev) in hci_core.h to return false did the trick."

I don't know how to do that #define lmp_bredr_capable(dev). Could someone help?

I'm fully available to test it.

2 Answers

i solved my problem by comment the lines 296 and 297 of hci_core.c(plus patches).

static void bredr_setup(struct hci_request *req)
{ __le16 param; __u8 flt_type; /* Read Buffer Size (ACL mtu, max pkt, etc.) */ hci_req_add(req, HCI_OP_READ_BUFFER_SIZE, 0, NULL); /* Read Class of Device */ hci_req_add(req, HCI_OP_READ_CLASS_OF_DEV, 0, NULL); /* Read Local Name */ hci_req_add(req, HCI_OP_READ_LOCAL_NAME, 0, NULL); /* Read Voice Setting */ hci_req_add(req, HCI_OP_READ_VOICE_SETTING, 0, NULL); /* Read Number of Supported IAC */ hci_req_add(req, HCI_OP_READ_NUM_SUPPORTED_IAC, 0, NULL); /* Read Current IAC LAP */ hci_req_add(req, HCI_OP_READ_CURRENT_IAC_LAP, 0, NULL); /* Clear Event Filters */ //flt_type = HCI_FLT_CLEAR_ALL; HERE!! //hci_req_add(req, HCI_OP_SET_EVENT_FLT, 1, &flt_type); /* Connection accept timeout ~20 secs */ param = cpu_to_le16(0x7d00); hci_req_add(req, HCI_OP_WRITE_CA_TIMEOUT, 2, &param);

Maybe the "#define lmp_bredr_capable(dev) 0" also work. But im not sure. I still run the bredr_setup() but bypass the clear event filter step...

obs: Its working flawless for 2 days. Only problem, i cant turn it into a HSP\HSP profile but i think its another story(even after the ofono gambiarra). Bluetooth in linux is a pain in a$..

I have found that just upgrading to Kernel 5.13.4 fixes the Fake Bluetooth CSR 0100 issue.

sudo add-apt-repository ppa:cappelikan/ppa

Then check updates and install the tool via commands:

sudo apt update
sudo apt install mainline

Search in Linux Programs Kernel Mainline updater and run the upgrade, reboot, Fake CSR Bluetooth working.