From 7adde1e5216e984480a7e29f00028951fd7f3dc1 Mon Sep 17 00:00:00 2001 From: Aritra Das Date: Thu, 3 Sep 2026 10:03:22 -0700 Subject: [PATCH] Bluetooth: btusb: Add USB ID 13d3:3556 for RTL8821CE The onboard Realtek RTL8821CE combo card on the ASUS PRIME B550-PLUS AC-HES presents its Bluetooth function as USB ID 13d3:3556. This ID is missing from quirks_table, so btusb matches the device only through the generic Bluetooth class entry in btusb_table and driver_info stays zero. BTUSB_REALTEK is therefore never set, btrtl never runs, and the controller keeps executing its on-chip ROM firmware instead of loading rtl_bt/rtl8821c_fw.bin and rtl_bt/rtl8821c_config.bin. In that state BLE HID peripherals are unusable. A HHKB Hybrid keyboard pairs and enumerates as a HID device, then the link drops within 10-30 seconds, repeatedly. The same keyboard is stable on the same host under other operating systems. Adding the ID lets btusb run the Realtek setup path: Bluetooth: hci0: RTL: examining hci_ver=08 hci_rev=000c lmp_ver=08 lmp_subver=8821 Bluetooth: hci0: RTL: rom_version status=0 version=1 Bluetooth: hci0: RTL: loading rtl_bt/rtl8821c_fw.bin Bluetooth: hci0: RTL: loading rtl_bt/rtl8821c_config.bin Bluetooth: hci0: RTL: cfg_sz 10, total sz 34926 Bluetooth: hci0: RTL: fw version 0x75b8f098 With the firmware loaded the same keyboard has stayed connected for over 11 hours without a single drop. Device descriptor: T: Bus=01 Lev=01 Prnt=01 Port=04 Cnt=02 Dev#= 2 Spd=12 MxCh= 0 D: Ver= 1.10 Cls=e0(wlcon) Sub=01 Prot=01 MxPS=64 #Cfgs= 1 P: Vendor=13d3 ProdID=3556 Rev=01.10 S: Manufacturer=Realtek S: Product=Bluetooth Radio S: SerialNumber=00e04c000001 C: #Ifs= 2 Cfg#= 1 Atr=e0 MxPwr=500mA I: If#= 0 Alt= 0 #EPs= 3 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb E: Ad=02(O) Atr=02(Bulk) MxPS= 64 Ivl=0ms E: Ad=81(I) Atr=03(Int.) MxPS= 16 Ivl=1ms E: Ad=82(I) Atr=02(Bulk) MxPS= 64 Ivl=0ms I: If#= 1 Alt= 0 #EPs= 2 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb E: Ad=03(O) Atr=01(Isoc) MxPS= 0 Ivl=1ms E: Ad=83(I) Atr=01(Isoc) MxPS= 0 Ivl=1ms Signed-off-by: Aritra Das Signed-off-by: Luiz Augusto von Dentz --- drivers/bluetooth/btusb.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c index cce5d9fb1c44..7e9ec286eb02 100644 --- a/drivers/bluetooth/btusb.c +++ b/drivers/bluetooth/btusb.c @@ -529,6 +529,8 @@ static const struct usb_device_id quirks_table[] = { BTUSB_WIDEBAND_SPEECH }, { USB_DEVICE(0x13d3, 0x3533), .driver_info = BTUSB_REALTEK | BTUSB_WIDEBAND_SPEECH }, + { USB_DEVICE(0x13d3, 0x3556), .driver_info = BTUSB_REALTEK | + BTUSB_WIDEBAND_SPEECH }, { USB_DEVICE(0x13d3, 0x3558), .driver_info = BTUSB_REALTEK | BTUSB_WIDEBAND_SPEECH },