Arch Linux : OSError: [Errno 123] No medium found: '/dev/sda'

[lucastanure]

`tanureal@cryzen usbsdmux $ source venv/bin/activate

(venv) tanureal@cryzen usbsdmux $ sudo venv/bin/usbsdmux /dev/sda get
Traceback (most recent call last):
File "/home/tanureal/workspace/usbsdmux/venv/bin/usbsdmux", line 10, in
sys.exit(main())
File "/home/tanureal/workspace/usbsdmux/venv/lib/python3.10/site-packages/usbsdmux-0.2.1-py3.10.egg/usbsdmux/main.py", line 97, in main
File "/home/tanureal/workspace/usbsdmux/venv/lib/python3.10/site-packages/usbsdmux-0.2.1-py3.10.egg/usbsdmux/main.py", line 79, in main
File "/home/tanureal/workspace/usbsdmux/venv/lib/python3.10/site-packages/usbsdmux-0.2.1-py3.10.egg/usbsdmux/usbsdmux.py", line 55, in get_mode
File "/home/tanureal/workspace/usbsdmux/venv/lib/python3.10/site-packages/usbsdmux-0.2.1-py3.10.egg/usbsdmux/pca9536.py", line 73, in read_register
File "/home/tanureal/workspace/usbsdmux/venv/lib/python3.10/site-packages/usbsdmux-0.2.1-py3.10.egg/usbsdmux/usb2642i2c.py", line 413, in write_read_to
File "/home/tanureal/workspace/usbsdmux/venv/lib/python3.10/site-packages/usbsdmux-0.2.1-py3.10.egg/usbsdmux/usb2642i2c.py", line 335, in _call_IOCTL
OSError: [Errno 123] No medium found: '/dev/sda'

(venv) tanureal@cryzen usbsdmux $ ls -l /dev/sda
brw-rw---- 1 777 disk 8, 0 Dec 4 10:43 /dev/sda
`

[lucastanure]

usbsdmux doesn't work on Arch Linux.
The device /dev/sda is created when I insert the USB cable into my host machine, but usbsdmux doesn't talk to it.

[Bastian-Krause]

usbsdmux talks to the SCSI generic device /dev/sgX, not /dev/sdX. See the README and the help text.

[lucastanure]

on arch linux kernel 6.0.11-arch1-1 the insertion of usbsdmux board doesn't create /dev/sgX devices.
Only /dev/sda.
[ 9238.242294] usb 7-3.3: new high-speed USB device number 8 using xhci_hcd
[ 9238.333687] usb 7-3.3: New USB device found, idVendor=0424, idProduct=2640, bcdDevice= 8.a2
[ 9238.333694] usb 7-3.3: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[ 9238.388888] hub 7-3.3:1.0: USB hub found
[ 9238.389078] hub 7-3.3:1.0: 1 port detected
[ 9238.668937] usb 7-3.3.1: new high-speed USB device number 9 using xhci_hcd
[ 9238.818296] usb 7-3.3.1: New USB device found, idVendor=0424, idProduct=4041, bcdDevice= 2.09
[ 9238.818304] usb 7-3.3.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 9238.818307] usb 7-3.3.1: Product: usb-sd-mux_rev4.0
[ 9238.818309] usb 7-3.3.1: Manufacturer: Linux Automation GmbH
[ 9238.818310] usb 7-3.3.1: SerialNumber: 000000001323
[ 9238.818771] usb-storage 7-3.3.1:1.0: USB Mass Storage device detected
[ 9238.819079] scsi host2: usb-storage 7-3.3.1:1.0
[ 9239.839308] scsi 2:0:0:0: Direct-Access LinuxAut sdmux HS-SD/MMC 2.09 PQ: 0 ANSI: 0
[ 9239.840213] sd 2:0:0:0: [sda] Media removed, stopped polling
[ 9239.841102] sd 2:0:0:0: [sda] Attached SCSI removable disk

[hnez]

Hi, that's strange.
I've just plugged an USB-SD-Mux into my Arch Machine and for me everything looks fine:

leonard@fulladder ~> uname -a
Linux fulladder 6.0.10-arch2-1 #1 SMP PREEMPT_DYNAMIC Sat, 26 Nov 2022 16:51:18 +0000 x86_64 GNU/Linux

leonard@fulladder ~> sudo dmesg | tail -n 15
[151042.487522] usb 1-5: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[151042.492601] hub 1-5:1.0: USB hub found
[151042.495491] hub 1-5:1.0: 1 port detected
[151042.795375] usb 1-5.1: new high-speed USB device number 6 using xhci_hcd
[151042.963585] usb 1-5.1: New USB device found, idVendor=0424, idProduct=4041, bcdDevice= 2.09
[151042.963594] usb 1-5.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[151042.963598] usb 1-5.1: Product: usb-sd-mux_rev4.0
[151042.963601] usb 1-5.1: Manufacturer: Linux Automation GmbH
[151042.963604] usb 1-5.1: SerialNumber: 000000000757
[151042.971619] usb-storage 1-5.1:1.0: USB Mass Storage device detected
[151042.971873] scsi host10: usb-storage 1-5.1:1.0
[151043.981281] scsi 10:0:0:0: Direct-Access     LinuxAut sdmux HS-SD/MMC  2.09 PQ: 0 ANSI: 0
[151043.981586] sd 10:0:0:0: Attached scsi generic sg3 type 0
[151043.982102] sd 10:0:0:0: [sdd] Media removed, stopped polling
[151043.982667] sd 10:0:0:0: [sdd] Attached SCSI removable disk

leonard@fulladder ~> ls /dev/sg*
/dev/sg0  /dev/sg1  /dev/sg2  /dev/sg3

I am not currently running the newest Kernel, as I did not come around to rebooting yet.
This leads to problems with hotplugging when I have already pacman -Syuu-ed but not yet rebooted, as this results in the kernel modules for the currently running kernel no longer being available in /lib/modules.
This should not be the case for you, as you are running the newest kernel, but could you check anyways if the sg module is available and loaded on your system?

leonard@fulladder ~> lsmod | grep sg
sg                     49152  0

leonard@fulladder ~> sudo modprobe sg

[lucastanure]

Hi,

I do have the module sg, but I had to manually insert it and now works

[hnez]

Huh, okay. I'would have expected the sg module to get loaded automatically, but it seems this is not the case for you.
Do you see any other /dev/sg devices now that the sg module is loaded?
In my case I have two SATA disks and a SATA optical drive. Maybe one of these has triggered the loading of the sg module.
Maybe your system does not have any such legacy devices.

We do have this section in the Troubleshooting section of the README:

• In order for the /dev/sg* device to appear the sg kernel module needs to be loaded into the kernel. This is usually done
  automatically by udev once the USB-SD-Mux is connected. To manually load the kernel module run sudo modprobe sg.

But I would prefer this manual step not to be required. (And for most users it is'nt)

[lucastanure]

yes, I only have nvme drives. I think your cdrom is triggering the load of sg.

Do you see any other /dev/sg devices now that the sg module is loaded?
No

[iperry]

Plugged this in today on kernel Arch Linux 6.6.8-arch1-1. Also found the same problem that was resolved by inserting the sg module. Not sure why it wasn't automatically loaded, happy to debug.

[pslldq]

An alternative to manually running modprobe would be echo sg > /etc/modules-load.d/usbsdmux.conf
This loads the sg module on every boot. See https://wiki.archlinux.org/title/Kernel_module#systemd