2021-06-08 18:24:56

by Alan Stern

[permalink] [raw]
Subject: Re: Strange problem with USB device

On Tue, Jun 08, 2021 at 12:41:23PM -0500, Larry Finger wrote:
> Hi,
>
> In https://bugzilla.suse.com/show_bug.cgi?id=1186889, a user is
> reporting that his Bluetooth component of a Realtek RTL8822CE is not

Is that a USB device? That is, does it connect to the computer
via a USB cable? I'll assume it does...

> being found in openSUSE's kernel 5.3.18. His lsusb scan is as follows:
>
> $ lsusb
> Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
> Bus 001 Device 003: ID 13d3:56c9 IMC Networks HP TrueVision HD Camera
> Bus 001 Device 002: ID 045e:07fd Microsoft Corp. Nano Transceiver 1.1
> Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
>
> The Bluetooth device is found and works in Windows 10, where the Device
> Manager reports hardware ID's of 0bda:b00c. This combination is in
> driver btusb.
>
> Is there a bug in the USB bus scan in kernel 5.3.18 that has since been
> fixed, or is there still a bug that misses this device?

Given only the information you have provided, it is impossible to
answer that question. Broadly speaking, lots of bugs in the USB
subsystem have been fixed since kernel 5.3.18, but I don't know
if any of them would affect detecting new devices on the bus like
this.

One thing you might try is to turn on USB debugging before
plugging in the device:

echo 'module usbcore =p' >/sys/kernel/debug/dynamic_debug/control

The additional information this adds to the dmesg log may be
helpful.

Alan Stern


2021-06-09 09:44:40

by Larry Finger

[permalink] [raw]
Subject: Re: Strange problem with USB device

On 6/8/21 1:20 PM, Alan Stern wrote:
> On Tue, Jun 08, 2021 at 12:41:23PM -0500, Larry Finger wrote:
>> Hi,
>>
>> In https://bugzilla.suse.com/show_bug.cgi?id=1186889, a user is
>> reporting that his Bluetooth component of a Realtek RTL8822CE is not
>
> Is that a USB device? That is, does it connect to the computer
> via a USB cable? I'll assume it does...
>
>> being found in openSUSE's kernel 5.3.18. His lsusb scan is as follows:
>>
>> $ lsusb
>> Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
>> Bus 001 Device 003: ID 13d3:56c9 IMC Networks HP TrueVision HD Camera
>> Bus 001 Device 002: ID 045e:07fd Microsoft Corp. Nano Transceiver 1.1
>> Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
>>
>> The Bluetooth device is found and works in Windows 10, where the Device
>> Manager reports hardware ID's of 0bda:b00c. This combination is in
>> driver btusb.
>>
>> Is there a bug in the USB bus scan in kernel 5.3.18 that has since been
>> fixed, or is there still a bug that misses this device?
>
> Given only the information you have provided, it is impossible to
> answer that question. Broadly speaking, lots of bugs in the USB
> subsystem have been fixed since kernel 5.3.18, but I don't know
> if any of them would affect detecting new devices on the bus like
> this.
>
> One thing you might try is to turn on USB debugging before
> plugging in the device:
>
> echo 'module usbcore =p' >/sys/kernel/debug/dynamic_debug/control
>
> The additional information this adds to the dmesg log may be
> helpful.

The BT device is part of the same card as the PCIe wifi device, thus there is no
"plugging" it in a conventional sense. Is there some way to add the usbcore
debugging statement to the kernel options line at boot time?

As I told GregKH, I am having the person with the problem try a rescue system
with a 5.12 kernel.

Larry