So after I experimented with disabling SMT (what Windows calls Hyper-Threading) to account for the SMT CPU vulnerability, found it slowed my computer down too much, and re-enabled SMT, I rebooted.
Then I found that Bluetooth had started acting strangely. It can be enabled, it searches for devices, it finds devices, but the list of devices doesn't show the device name, it only shows, for instance, "Audio device" and "Computer device", and I can't click on them to connect.
I didn't have any Bluetooth devices connected yet on this install. I noticed this problem because "Bluetooth Off" and "Bluetooth On" had disappeared from the pop-up menu (where you set volume and screen brightness) at the bottom-right of the screen. Now it only shows up when Bluetooth is on, and disappears from that menu when Bluetooth is off.
dmesg | grep -i 'blue' shows:
[ 1034.386471] Bluetooth: hci0: urb 00000000edad6988 failed to resubmit (2)
Here's some troubleshooting I've done:
dmesg | grep -i 'blue'
[ 17.874499] Bluetooth: Core ver 2.22
[ 17.874533] NET: Registered PF_BLUETOOTH protocol family
[ 17.874535] Bluetooth: HCI device and connection manager initialized
[ 17.874543] Bluetooth: HCI socket layer initialized
[ 17.874547] Bluetooth: L2CAP socket layer initialized
[ 17.874552] Bluetooth: SCO socket layer initialized
[ 24.885051] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[ 24.885057] Bluetooth: BNEP filters: protocol multicast
[ 24.885063] Bluetooth: BNEP socket layer initialized
[ 32.136833] Bluetooth: RFCOMM TTY layer initialized
[ 32.136843] Bluetooth: RFCOMM socket layer initialized
[ 32.136850] Bluetooth: RFCOMM ver 1.11
**[ 1034.386471] Bluetooth: hci0: urb 00000000edad6988 failed to resubmit (2)**
rfkill list
0: phy0: Wireless LAN
Soft blocked: no
Hard blocked: no
2: hci0: Bluetooth
Soft blocked: no
Hard blocked: no
hciconfig -a
hci0: Type: Primary Bus: USB
BD Address: 4C:80:93:3B:35:2F ACL MTU: 310:10 SCO MTU: 64:8
UP RUNNING PSCAN ISCAN
RX bytes:10440 acl:0 sco:0 events:703 errors:0
TX bytes:21584 acl:0 sco:0 commands:568 errors:0
Features: 0xff 0xff 0x8f 0xfe 0x9b 0xff 0x59 0x87
Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3
Link policy: RSWITCH HOLD SNIFF PARK
Link mode: SLAVE ACCEPT
Name: 'Dell-Inspiron-N7110'
Class: 0x1c010c
Service Classes: Rendering, Capturing, Object Transfer
Device Class: Computer, Laptop
HCI Version: 3.0 (0x5) Revision: 0x1b07
LMP Version: 3.0 (0x5) Subversion: 0xfc00
Manufacturer: Intel Corp. (2)
bluetoothctl
Agent registered
[CHG] Controller 4C:80:93:3B:35:2F Pairable: yes
[bluetooth]# show
Controller 4C:80:93:3B:35:2F (public)
Name: Dell-Inspiron-N7110
Alias: Dell-Inspiron-N7110
Class: 0x001c010c
Powered: yes
Discoverable: yes
DiscoverableTimeout: 0x00000000
Pairable: yes
UUID: A/V Remote Control (0000110e-0000-1000-8000-00805f9b34fb)
UUID: PnP Information (00001200-0000-1000-8000-00805f9b34fb)
UUID: Message Access Server (00001132-0000-1000-8000-00805f9b34fb)
UUID: Audio Sink (0000110b-0000-1000-8000-00805f9b34fb)
UUID: Message Notification Se.. (00001133-0000-1000-8000-00805f9b34fb)
UUID: Phonebook Access Server (0000112f-0000-1000-8000-00805f9b34fb)
UUID: A/V Remote Control Target (0000110c-0000-1000-8000-00805f9b34fb)
UUID: OBEX Object Push (00001105-0000-1000-8000-00805f9b34fb)
UUID: IrMC Sync (00001104-0000-1000-8000-00805f9b34fb)
UUID: OBEX File Transfer (00001106-0000-1000-8000-00805f9b34fb)
UUID: Vendor specific (00005005-0000-1000-8000-0002ee000001)
UUID: Audio Source (0000110a-0000-1000-8000-00805f9b34fb)
UUID: Headset (00001108-0000-1000-8000-00805f9b34fb)
UUID: Headset AG (00001112-0000-1000-8000-00805f9b34fb)
Modalias: usb:v1D6Bp0246d0535
Discovering: no
[bluetooth]# info 4C:80:93:3B:35:2F
**Device 4C:80:93:3B:35:2F not available**
sudo btmon
Bluetooth monitor ver 5.53
= Note: Linux version 5.15.0-53-generic (x86_64) 0.127488
= Note: Bluetooth subsystem version 2.22 0.127491
= New Index: 4C:80:93:3B:35:2F (Primary,USB,hci0) [hci0] 0.127492
= Open Index: 4C:80:93:3B:35:2F [hci0] 0.127492
= Index Info: 4C:80:93:3B:35:2F (Intel Corp.) [hci0] 0.127493
@ MGMT Open: bluetoothd (privileged) version 1.21 {0x0001} 0.127494
@ MGMT Open: btmon (privileged) version 1.21 {0x0002} 0.127629
[I opened Bluetooth Settings here]
@ MGMT Command: Set Bondable (0x0009) plen 1 {0x0001} [hci0] 17.292349
Bondable: Enabled (0x01)
@ MGMT Event: Command Complete (0x0001) plen 7 {0x0001} [hci0] 17.292359
Set Bondable (0x0009) plen 4
Status: Success (0x00)
Current settings: 0x000000db
Powered
Connectable
Discoverable
Bondable
Secure Simple Pairing
BR/EDR
@ MGMT Event: New Settings (0x0006) plen 4 {0x0002} [hci0] 17.292361
Current settings: 0x000000db
Powered
Connectable
Discoverable
Bondable
Secure Simple Pairing
BR/EDR
@ MGMT Command: Set IO Capability (0x0018) plen 1 {0x0001} [hci0] 17.292400
Capability: DisplayYesNo (0x01)
@ MGMT Event: Command Complete (0x0001) plen 3 {0x0001} [hci0] 17.292403
Set IO Capability (0x0018) plen 0
Status: Success (0x00)
@ MGMT Command: Start Service Discovery (0x003a) plen 4 {0x0001} [hci0] 17.557279
Address type: 0x01
BR/EDR
RSSI: invalid (0x7f)
UUIDs: 0
< HCI Command: Inquiry (0x01|0x0001) plen 5 #1 [hci0] 17.557492
Access code: 0x9e8b33 (General Inquiry)
Length: 10.24s (0x08)
Num responses: 0
> HCI Event: Command Status (0x0f) plen 4 #2 [hci0] 17.693121
Inquiry (0x01|0x0001) ncmd 1
Status: Success (0x00)
@ MGMT Event: Command Complete (0x0001) plen 4 {0x0001} [hci0] 17.693287
Start Service Discovery (0x003a) plen 1
Status: Success (0x00)
Address type: 0x01
BR/EDR
@ MGMT Event: Discovering (0x0013) plen 2 {0x0002} [hci0] 17.693310
Address type: 0x01
BR/EDR
Discovery: Enabled (0x01)
@ MGMT Event: Discovering (0x0013) plen 2 {0x0001} [hci0] 17.693310
Address type: 0x01
BR/EDR
Discovery: Enabled (0x01)
> HCI Event: Inquiry Complete (0x01) plen 1 #3 [hci0] 28.083730
Status: Success (0x00)
[I disabled Bluetooth in Bluetooth Settings here]
@ MGMT Event: Discovering (0x0013) plen 2 {0x0002} [hci0] 28.083863
Address type: 0x01
BR/EDR
Discovery: Disabled (0x00)
@ MGMT Event: Discovering (0x0013) plen 2 {0x0001} [hci0] 28.083863
Address type: 0x01
BR/EDR
Discovery: Disabled (0x00)
[I re-enabled Bluetooth in Bluetooth Settings here]
@ MGMT Command: Start Service Discovery (0x003a) plen 4 {0x0001} [hci0] 28.557593
Address type: 0x01
BR/EDR
RSSI: invalid (0x7f)
UUIDs: 0
< HCI Command: Inquiry (0x01|0x0001) plen 5 #4 [hci0] 28.557670
Access code: 0x9e8b33 (General Inquiry)
Length: 10.24s (0x08)
Num responses: 0
> HCI Event: Command Status (0x0f) plen 4 #5 [hci0] 28.559784
Inquiry (0x01|0x0001) ncmd 1
Status: Success (0x00)
@ MGMT Event: Command Complete (0x0001) plen 4 {0x0001} [hci0] 28.559915
Start Service Discovery (0x003a) plen 1
Status: Success (0x00)
Address type: 0x01
BR/EDR
@ MGMT Event: Discovering (0x0013) plen 2 {0x0002} [hci0] 28.559921
Address type: 0x01
BR/EDR
Discovery: Enabled (0x01)
@ MGMT Event: Discovering (0x0013) plen 2 {0x0001} [hci0] 28.559921
Address type: 0x01
BR/EDR
Discovery: Enabled (0x01)
> HCI Event: Inquiry Complete (0x01) plen 1 #6 [hci0] 38.951265
Status: Success (0x00)
@ MGMT Event: Discovering (0x0013) plen 2 {0x0002} [hci0] 38.951315
Address type: 0x01
BR/EDR
Discovery: Disabled (0x00)
@ MGMT Event: Discovering (0x0013) plen 2 {0x0001} [hci0] 38.951315
Address type: 0x01
BR/EDR
Discovery: Disabled (0x00)
@ MGMT Command: Start Service Discovery (0x003a) plen 4 {0x0001} [hci0] 39.557097
Address type: 0x01
BR/EDR
RSSI: invalid (0x7f)
UUIDs: 0
< HCI Command: Inquiry (0x01|0x0001) plen 5 #7 [hci0] 39.557171
Access code: 0x9e8b33 (General Inquiry)
Length: 10.24s (0x08)
Num responses: 0
> HCI Event: Command Status (0x0f) plen 4 #8 [hci0] 39.559396
Inquiry (0x01|0x0001) ncmd 1
Status: Success (0x00)
@ MGMT Event: Command Complete (0x0001) plen 4 {0x0001} [hci0] 39.559489
Start Service Discovery (0x003a) plen 1
Status: Success (0x00)
Address type: 0x01
BR/EDR
@ MGMT Event: Discovering (0x0013) plen 2 {0x0002} [hci0] 39.559494
Address type: 0x01
BR/EDR
Discovery: Enabled (0x01)
@ MGMT Event: Discovering (0x0013) plen 2 {0x0001} [hci0] 39.559494
Address type: 0x01
BR/EDR
Discovery: Enabled (0x01)
> HCI Event: Inquiry Complete (0x01) plen 1 #9 [hci0] 49.952058
Status: Success (0x00)
@ MGMT Event: Discovering (0x0013) plen 2 {0x0002} [hci0] 49.952194