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绿联USB蓝牙模块冒牌芯片

发布时间:2024年08月18日评论数：抢沙发阅读数：37

20年21年的时候买的一个USB蓝牙，绿联的，记得三十块左右，当时可以用的，很久没用了。

拿到一个无线鼠标，罗技M240，标配竟然不带接收器，可以用蓝牙连，于是用这个USB蓝牙模块试试。

kernel里选上蓝牙部分，电脑启动后，dmesg能识别到，bluetooth能scan，能discover和被discover，就是不能连上。gnome设置中心也不对劲，显示无蓝牙设备。

调了一天，毛用没有。最后看到驱动btusb.c里的注释：

        /* Detect a wide host of Chinese controllers that aren't CSR.
         *
         * Known fake bcdDevices: 0x0100, 0x0134, 0x1915, 0x2520, 0x7558, 0x8891
         *
         * The main thing they have in common is that these are really popular low-cost
         * options that support newer Bluetooth versions but rely on heavy VID/PID
         * squatting of this poor old Bluetooth 1.1 device. Even sold as such.
         *
         * We detect actual CSR devices by checking that the HCI manufacturer code
         * is Cambridge Silicon Radio (10) and ensuring that LMP sub-version and
         * HCI rev values always match. As they both store the firmware number.
         */

        /* Known legit CSR firmware build numbers and their supported BT versions:
         * - 1.1 (0x1) -> 0x0073, 0x020d, 0x033c, 0x034e
         * - 1.2 (0x2) ->                 0x04d9, 0x0529
         * - 2.0 (0x3) ->         0x07a6, 0x07ad, 0x0c5c
         * - 2.1 (0x4) ->         0x149c, 0x1735, 0x1899 (0x1899 is a BlueCore4-External)
         * - 4.0 (0x6) ->         0x1d86, 0x2031, 0x22bb
         *
         * e.g. Real CSR dongles with LMP subversion 0x73 are old enough that
         *      support BT 1.1 only; so it's a dead giveaway when some
         *      third-party BT 4.0 dongle reuses it.
         */

                /* Generally these clones have big discrepancies between
                 * advertised features and what's actually supported.
                 * Probably will need to be expanded in the future;
                 * without these the controller will lock up.
                 */

[  107.086515] usb 1-3: new full-speed USB device number 11 using xhci_hcd
[  107.510368] usb 1-3: New USB device found, idVendor=0a12, idProduct=0001, bcdDevice=88.91
[  107.510376] usb 1-3: New USB device strings: Mfr=0, Product=2, SerialNumber=0
[  107.510379] usb 1-3: Product: CSR8510 A10
[  107.533144] Bluetooth: hci0: CSR: Setting up dongle with HCI ver=6 rev=22bb
[  107.533149] Bluetooth: hci0: LMP ver=6 subver=22bb; manufacturer=10
[  107.757312] Bluetooth: MGMT ver 1.22

BCD号码正是8891，冒牌假芯片，都被封杀到 kernel 的注释里去了，真行。(当前的kernel版本: 6.6.38，两年前的kernel记得是没问题的)