** Changed in: linux (Ubuntu Bionic)
Status: New => Fix Committed
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https://bugs.launchpad.net/bugs/1810797
Title:
bluetooth controller not detected with 4.15 kernel
Status in linux package in Ubuntu:
Fix Committed
Status in linux-snapdragon package in Ubuntu:
Invalid
Status in linux source package in Bionic:
Fix Committed
Status in linux-snapdragon source package in Bionic:
Invalid
Bug description:
Impact:
Upon boot, no hci device is available to userspace, thus bluetooth
communication is not possible.
Defect analysis:
The root of the problem lies in these two patches:
$ git log --online drivers/bluetooth/btqcomsmd.c
...
766154b Bluetooth: btqcomsmd: retrieve BD address from DT property
6e51811 Bluetooth: btqcomsmd: Add support for BD address setup
...
Qualcomm engineer found that btqcomsmd had no BD address burned in
(nor via ROM, neither internally) and it was always coming up with the
same address, probably derived from manufacturer ID and / or chip ID.
To fix this, they pushed the burden of generating a unique per-board
BD address to the Qualcomm bootloader and make it pass down via DTB to
the live kernel - and if no address was present in the DTB, the hci
was left unconfigured.
Fix:
So *technically* speaking, the kernel is correct in this case, it's
our dragonboard image (e.g. Ubuntu Core) that doesn't extract the
generated BD address from the Qualcomm bootloader and pass it down to
the kernel.
On the other hand, having Bluetooth working out of the box (even with
a dummy address), is a nice feature to have, so i slightly modified
Qualcomm's code introduced in the two above patches, and made the lack
of BD address in DTB non fatal:
if BD_is_present_in_DTB()
read_BD_and_apply_setup()
else
let_hci_core_generate_BD()
end if
And surrounded the modification in #ifdef...#endif brackets to keep it
local.
How to test:
By default, on a patched kernel, the hci device will have a default
address:
ubuntu@dragon410c:~$ hcitool dev
Devices:
hci0 00:00:00:00:5A:AD
the address " 00:00:00:00:5A:AD" might vary, but will be consistent
after every reboot.
The other option is to specify a custom BD address, e.g. using uboot
to manipulate the dtb - we assume the dtb was loaded in memory at
${fdt_addr}:
dragonboard410c => fdt addr ${fdt_addr}
dragonboard410c => fdt print /soc/wcnss/smd-edge/wcnss/bt/
bt {
compatible = "qcom,wcnss-bt";
};
dragonboard410c => fdt resize
dragonboard410c => fdt set /soc/wcnss/smd-edge/wcnss/bt/ local-bd-
address [ 55 44 33 22 11 00 ]
dragonboard410c => fdt print /soc/wcnss/smd-edge/wcnss/bt/
bt {
local-bd-address = [55 44 33 22 11 00];
compatible = "qcom,wcnss-bt";
};
then proceed with the rest of the boot process and check hci:
$ hcitool dev
Devices:
hci0 00:11:22:33:44:55
In both cases, blueooth work afterward, and can be used to communicate
with other devices:
ubuntu@dragon410c:~$ hcitool scan
Scanning ...
C0:BD:54:12:4E:D1 My dummy device
Regression potential:
None, the fix is surronded with #ifdef...#endif thus it doesn't exist
outside of it.
--
Using the core18 image from
http://cdimage.ubuntu.com/ubuntu-core/18/stable/current/
Kernel snap: 4.15.0-39.42 (72)
rfkill shows there is an hci0 device:
$ rfkill list
0: hci0: Bluetooth
Soft blocked: no
Hard blocked: no
1: phy0: Wireless LAN
Soft blocked: no
Hard blocked: no
But bluetoothctl does not detect any controller:
$ sudo bluetoothctl
08:58 Agent registered
08:58 [bluetooth]# list
[...no output...]
If you revert to the 4.4 kernel [4.4.0-1106.111 (76)] it works:
$ sudo bluetoothctl
[NEW] Controller 00:00:00:00:5A:AD BlueZ 5.47 [default]
Agent registered
[bluetooth]# list
Controller 00:00:00:00:5A:AD BlueZ 5.47 [default]
[bluetooth]# show
Controller 00:00:00:00:5A:AD
Name: BlueZ 5.47
Alias: BlueZ 5.47
Class: 0x00000000
Powered: no
Discoverable: no
Pairable: yes
UUID: Generic Attribute Profile (00001801-0000-1000-8000-00805f9b34fb)
UUID: A/V Remote Control (0000110e-0000-1000-8000-00805f9b34fb)
UUID: OBEX File Transfer (00001106-0000-1000-8000-00805f9b34fb)
UUID: Generic Access Profile (00001800-0000-1000-8000-00805f9b34fb)
UUID: OBEX Object Push (00001105-0000-1000-8000-00805f9b34fb)
UUID: PnP Information (00001200-0000-1000-8000-00805f9b34fb)
UUID: A/V Remote Control Target (0000110c-0000-1000-8000-00805f9b34fb)
UUID: IrMC Sync (00001104-0000-1000-8000-00805f9b34fb)
UUID: Vendor specific (00005005-0000-1000-8000-0002ee000001)
UUID: Message Notification Se.. (00001133-0000-1000-8000-00805f9b34fb)
UUID: Phonebook Access Server (0000112f-0000-1000-8000-00805f9b34fb)
UUID: Message Access Server (00001132-0000-1000-8000-00805f9b34fb)
Modalias: usb:v1D6Bp0246d052F
Discovering: no
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