Comment 0 for bug 1790454

I run cosmic on my Dell Latitude E7470, which has an intel usb bluetooth device (8087:0a2b).

Sometimes (not every time) after a suspend/resume cycle, my laptop's bluetooth stops working. hciconfig shows:

hci0: Type: Primary Bus: USB
 BD Address: 00:00:00:00:00:00 ACL MTU: 0:0 SCO MTU: 0:0
 DOWN
 RX bytes:0 acl:0 sco:0 events:0 errors:0
 TX bytes:3 acl:0 sco:0 commands:1 errors:0

and dmesg tells me (various combinations of):

[237660.728312] Bluetooth: hci0: command tx timeout
[237732.339965] Bluetooth: hci0: command 0xfc05 tx timeout
[237925.202500] Bluetooth: hci0: Reading Intel version information failed (-110)

Trying to reinitialize the device by reloading the driver has no effect:

╰─▶ modprobe -r btusb; modprobe -r btintel; modprobe btintel; modprobe btusb

shows in dmesg:

[237938.219190] usbcore: deregistering interface driver btusb
[237938.601731] usbcore: registered new interface driver btusb
[237940.626392] Bluetooth: hci0: Reading Intel version information failed (-110)
[237940.626426] Bluetooth: hci0: command tx timeout

Strangely enough, reloading the module sometimes does work, upon which the kernel tells me :
aug 20 15:36:08 regan kernel: usbcore: deregistering interface driver btusb
aug 20 15:36:30 regan kernel: Bluetooth: hci0: Bootloader revision 0.0 build 2 week 52 2014
aug 20 15:36:30 regan kernel: usbcore: registered new interface driver btusb
aug 20 15:36:30 regan kernel: Bluetooth: hci0: Device revision is 5
aug 20 15:36:30 regan kernel: Bluetooth: hci0: Secure boot is enabled
aug 20 15:36:30 regan kernel: Bluetooth: hci0: OTP lock is enabled
aug 20 15:36:30 regan kernel: Bluetooth: hci0: API lock is enabled
aug 20 15:36:30 regan kernel: Bluetooth: hci0: Debug lock is disabled
aug 20 15:36:30 regan kernel: Bluetooth: hci0: Minimum firmware build 1 week 10 2014
aug 20 15:36:30 regan kernel: Bluetooth: hci0: Found device firmware: intel/ibt-11-5.sfi
aug 20 15:36:31 regan kernel: Bluetooth: hci0: Waiting for firmware download to complete
aug 20 15:36:31 regan kernel: Bluetooth: hci0: Firmware loaded in 1590852 usecs
aug 20 15:36:31 regan kernel: Bluetooth: hci0: Waiting for device to boot
aug 20 15:36:31 regan kernel: Bluetooth: hci0: Device booted in 11654 usecs
aug 20 15:36:31 regan kernel: Bluetooth: hci0: Found Intel DDC parameters: intel/ibt-11-5.ddc
aug 20 15:36:31 regan kernel: Bluetooth: hci0: Applying Intel DDC parameters completed

Looking further back in the kernel log, the difference between failed and successful resumes seems to be this:

Resume with broken bt:
[236481.370814] Restarting tasks ...
[236491.580841] Bluetooth: hci0: Reading Intel boot parameters failed (-110)

Resume with working bt:
[16562.706263] Restarting tasks ...
[16562.709034] Bluetooth: hci0: Bootloader revision 0.0 build 2 week 52 2014
[16562.716050] Bluetooth: hci0: Device revision is 5
[16562.716052] Bluetooth: hci0: Secure boot is enabled
[16562.716053] Bluetooth: hci0: OTP lock is enabled
[16562.716054] Bluetooth: hci0: API lock is enabled
[16562.716055] Bluetooth: hci0: Debug lock is disabled
[16562.716056] Bluetooth: hci0: Minimum firmware build 1 week 10 2014
[16562.716404] Bluetooth: hci0: Found device firmware: intel/ibt-11-5.sfi
[16564.202470] Bluetooth: hci0: Waiting for firmware download to complete
[16564.203017] Bluetooth: hci0: Firmware loaded in 1459449 usecs
[16564.203091] Bluetooth: hci0: Waiting for device to boot
[16564.215021] Bluetooth: hci0: Device booted in 11693 usecs
[16564.215080] Bluetooth: hci0: Found Intel DDC parameters: intel/ibt-11-5.ddc
[16564.219033] Bluetooth: hci0: Applying Intel DDC parameters completed

and everything works fine after that.

The first kernel on which this error occurred was 4.17.0-6-generic. Before that, I used 4.15.0-25-generic which works perfectly.