Hello maintainers of hw-detect,

I have an USB wireless adapter that uses the r8712u kernel module and
that requires firmware from non-free-firmware.
When I run the Debian installer, the missing firmware file is correctly
identified and installed by 'check-missing-firmware.sh'. However, the
kernel module is mis-identified as 'usb'. When I disconnect the adapter
and reconnect it, the installer is able to use the adapter properly.

Attached is a patch that allows the module to be identified correctly.
If desired, I can send the patch instead as a merge request on Salsa.

However, using 'modprobe -r r8712u' and 'modprobe r8712u' is not
sufficient to enable the adapter, it still needs a physical reconnect.
In the attached screenshot from the installer (sid) the result of the
patch is shown. Also in the QEMU environment, I need to disconnect and
reconnect the USB device from the host.

I tried several options, but could not get them to work: bind/unbind [1]
authorized, usbreset [2]
Do you know a solution (apart from a physical reconnect)?

With kind regards,
Roland Clobus

[1]
https://superuser.com/questions/1707773/how-to-turn-usb-connected-device-on-and-off-in-linux
[2]
https://askubuntu.com/questions/645/how-do-you-reset-a-usb-device-from-the-command-line

Hoi,

Roland Clobus <rclobus@rclobus.nl> (2024-05-25):

Just to confirm, which linux version was this tested against?

As you found out, having 'usb' is rather widespread, hence the existence
of the function you patched. What seems weird to my (not at all expert
in the kernel area) eyes is the unbound thing that led you to introduce
that special case.

I see that's a module from staging, maybe it's not behaving like it
should? At least differently from other modules…

I spotted 1422b526fba994cf05fd288a152106563b875fce that fixed a race
condition regarding firmware loading (fix available in v6.6-rc1 and
v6.1.52), maybe there are other similar issues?

I'd suggest a search in upstream bugzilla and mailing lists.

I'm adding the kernel maintainers in copy, in case they have better
ideas.


Cheers,

This is a more generic issue already reported in #1033679
<https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1033679>

Can you give a try to the attached patches ? They came to late for
bookworm, maybe it is time to reconsider them.

IMO $address should be included in the search pattern. Else if there is
another device reported as "usb" then your patch will wrongly resolve it
as r8712u too.

Looks like a driver/device issue.

I've used a locally built live image based on sid (live-build) with the
patched hw-detect.
...

As far as I can see, r8712u entered staging in 2012 and has been there
since...

In which repo can I find this hash value?
...
...>> Do you know a solution (apart from a physical reconnect)?

Thanks. I'll try to look some more.

With kind regards,
Roland Clobus

Hello Pascal,

Your patch series works fine, the firmware is correctly identified and
loaded. Unfortunately for me, it still needs a reconnect cycle.
See the attached syslog for their effect. (I've used sid)

At 19:30:58 the 'no network card is detected' dialog from the installer
is shown
At 19:32:30 I disconnected the USB device from KVM (which is attached on
the host)
At 19:32:45 I reconnected the USB device in KVM
At 19:34:06 the SSID scan shows the available wireless networks

Your patch is better and more generic. It would be a good candidate for
at least trixie.

Given that within kvm (virt-manager) I can simulate a reconnect, I would
expect that it can be simulated otherwise, but haven't found a proper
way yet.

With kind regards,
Roland Clobus

Thank you for testing my patches but I did not expect them to solve the
reattachment issue, only to identify the right module.

After the r8712u module is first loaded without the firmware then
unloaded and reloaded, what is the output of

ls -d /sys/bus/usb/drivers/r8712u/1-3*
ls -d /sys/bus/usb/devices/1-3/1-3*

assuming the wireless adapter is identified as 1-3 ?

* A live-build-based image with the Debian installer, generated for sid
   with in config/packages the hw-detect.udeb with the patches from #1033679
* Virtual-Manager boots the ISO image (UEFI secure boot)
* When the GRUB menu is shown, I attach the USB network adapter from the
host
* I select the Debian installer

* Moment 1: the first d-i screen is shown. The USB device is seen by the
kernel, but the module is not yet loaded
ls -d /sys/bus/usb/drivers/r8712u/1-3*
No such file or directory
ls -d /sys/bus/usb/drivers/usb/1-3*
/sys/bus/usb/drivers/usb/1-3
ls -d /sys/bus/usb/devices/1-3/1-3*
/sys/bus/usb/devices/1-3/1-3:1:0
lsmod | grep r8712u
<empty>

* Moment 2: the d-i screen 'No Ethernet card was detected' is shown
(The firmware has been placed where it can be found, module r8712u has
been removed and added)
ls -d /sys/bus/usb/drivers/r8712u/1-3*
No such file or directory
ls -d /sys/bus/usb/drivers/usb/1-3*
No such file or directory
ls -d /sys/bus/usb/devices/1-3/1-3*
No such file or directory
lsmod | grep r8712u
r8712u     262144   0
cfg80211  1355776  1 r8712u
usbcore    409600  5 xhci_hcd,usbhib,r8712u,usb_storage,xhci_pci

* Moment 3: I disconnect and reconnect the USB device in virt-manager
and select 'Detect network hardware' from the d-i menu. d-i shows a list
of SSIDs
ls -d /sys/bus/usb/drivers/r8712u/1-3*
/sys/bus/usb/drivers/r8712u/1-3:1.0
ls -d /sys/bus/usb/drivers/usb/1-3*
/sys/bus/usb/drivers/usb/1-3
ls -d /sys/bus/usb/devices/1-3/1-3*
/sys/bus/usb/devices/1-3/1-3:1:0
lsmod | grep r8712u
r8712u     262144   0
cfg80211  1355776  1 r8712u
usbcore    409600  5 xhci_hcd,usbhib,r8712u,usb_storage,xhci_pci

With kind regards,
Roland Clobus

As expected, the module is not loaded so /sys/bus/usb/drivers/r8712u
does not exist.

The device is present.
The module is loaded so /sys/bus/usb/drivers/r8712u should exist but is
not associated with the device.

It looks like the device is not present any more. But there was no
disconnect message in the kernel log. All I can see it the reset
message, but AFAICS a reset should not remove the device. Maybe it was
disabled or powered down.

I do not know enough about the kernel and USB subsystem to have any clue
about what is wrong. Maybe running "udevadm trigger" during specific
moments and recording its output may provide useful information:
- when the adapter is connected
- when the module is loaded without the firmware
- when the adapter is disconnected
- when the module is reloaded with the firmware

You do not have to run check-missing-firmware for this, you can run
modprobe commands in a shell.

As expected, the device is associated with the driver.

Sorry, I meant "udevadm monitor".