Hello everyone
and best wishes for 2023 :)
I have an old
Garmin Drive Smart 50 GPS and I want to be able
to attach it when it is in preboot mode to a VM hosted
by a Debian 11 host.
From what I understand, the preboot
mode allows us to flash a firmware before the GPS
actually starts (used among other things when the GPS
is soft bricked).
When I connect the GPS to the host it gives:
root@host:~#
journalctl -kf
# GPS in MTP storage mode (default when reset)
...
janv. 23 23:02:51 host kernel: usb 2-4: New USB
device found, idVendor=091e, idProduct=48db, bcdDevice= 0.01
janv. 23 23:02:51 host kernel: usb 2-4: New USB
device strings: Mfr=1, Product=2, SerialNumber=5
...
# GPS in mass storage mode
...
janv. 23 23:01:29 host kernel: usb 2-4: New USB
device found, idVendor=091e, idProduct=28db, bcdDevice= 5.09
janv. 23 23:01:29 host kernel: usb 2-4: New USB
device strings: Mfr=0, Product=0, SerialNumber=5
...
# GPS in preboot mode
...
janv. 23 23:09:05 host kernel: usb 2-4: New USB
device found, idVendor=091e, idProduct=0003, bcdDevice= 0.01
janv. 23 23:09:05 host kernel: usb 2-4: New USB
device strings: Mfr=0, Product=0, SerialNumber=0
janv. 23 23:09:13 host kernel: garmin_gps ttyUSB0:
Garmin GPS usb/tty converter now disconnected from ttyUSB0
...
We see that idVendor, idProduct, bcdDevice, Mfr, Product and SerialNumber vary according to the modes. We also see that the GPS is seen as a ttyUSB0 serial device.
I managed to attach the GPS in preboot mode, thanks to a script which waits for the GPS to be detected in this mode (not detailed here so as not to overload, but I can publish it if necessary) and which attaches to a VM in running (successfully tested on Debian 11 and Windows 7 guests).
Here is the code that generates the XML before attaching it :
...
echo "<serial type='dev'>
\
<source path='"$( \
ls -1 /dev/tty* | grep
-Ev "tty(|S?[0-9]+)$" \
)"'/> \
<target
type='usb-serial'> \
<vendor
id='0x"$( \
echo 091e \
)"'/> \
<product
id='0x"$( \
echo 28db \
)"'/> \
</target> \
</serial>" >
serial_device.xml
virsh attach-device vm-bullseye
--file serial_device.xml &
...
But once attached, this is what I see in the XML configuration of my VM (from virt-manager) :
<serial
type="dev">
<source
path="/dev/ttyUSB1"/>
<target
type="usb-serial" port="1">
<model
name="usb-serial"/>
</target>
<alias
name="serial1"/>
<address type="usb"
bus="0" port="4"/>
</serial>
We see that libvirt
has removed the vendor/product
id from the XML.
Also here is what I get from a Debian 11 guest :
root@vm-bullseye:~#
journalctl -k -f
...
janv. 23 21:26:22
vm-bullseye kernel: usb 3-2: new
full-speed USB device number 2
using uhci_hcd
janv. 23 21:26:22
vm-bullseye kernel: usb 3-2: New
USB device found, idVendor=0403,
idProduct=6001, bcdDevice= 4.00
janv. 23 21:26:22
vm-bullseye kernel: usb 3-2: New
USB device strings: Mfr=1,
Product=2, SerialNumber=4
janv. 23 21:26:22
vm-bullseye kernel: usb 3-2:
Product: QEMU USB SERIAL
janv. 23 21:26:22
vm-bullseye kernel: usb 3-2:
Manufacturer: QEMU
janv. 23 21:26:22
vm-bullseye kernel: usb 3-2:
SerialNumber: 1-0000:00:05.7-4
janv. 23 21:26:22
vm-bullseye kernel: usbcore:
registered new interface driver
usbserial_generic
janv. 23 21:26:22
vm-bullseye kernel: usbserial: USB
Serial support registered for
generic
janv. 23 21:26:22
vm-bullseye kernel: usbcore:
registered new interface driver
ftdi_sio
janv. 23 21:26:22
vm-bullseye kernel: usbserial: USB
Serial support registered for FTDI
USB Serial Device
janv. 23 21:26:22
vm-bullseye kernel: ftdi_sio
3-2:1.0: FTDI USB Serial Device
converter detected
janv. 23 21:26:22
vm-bullseye kernel: usb 3-2:
Detected FT232BM
janv. 23 21:26:22
vm-bullseye kernel: usb 3-2: FTDI
USB Serial Device converter now
attached to ttyUSB0
janv. 23 21:26:25
vm-bullseye kernel: usb 3-2: USB
disconnect, device number 2
janv. 23 21:26:25
vm-bullseye kernel: ftdi_sio
ttyUSB0: FTDI USB Serial Device
converter now disconnected from
ttyUSB0
janv. 23 21:26:25
vm-bullseye kernel: ftdi_sio
3-2:1.0: device disconnected
...
The
guest sees the GPS well but
idVendor=0403,
idProduct=6001,
bcdDevice=4.00, Mfr=1,
Product=2, SerialNumber=4
...
do not correspond to anything,
and tools that expect GPS in
preboot mode do not see
it.
My
questions :
Q1 : Is it
possible ?
Q2
: Am I doing it the right way
?
Q3
: Is there a method to pass
such a device directly
(pass-through) ?
Thank you in advance for the time you are going to devote to me :)
With Adelphity,
lnj
