Cheatsheet¶

A collection of useful commands and tips.

Hardware¶

To check the PCIe generation and speed of devices:

Identify the Device: Find the device's Bus, Device, and Function numbers (e.g., 01:00.0).
```
lspci
```
Get Detailed Information: Use the identifier to query the device.
```
sudo lspci -s 01:00.0 -vvv | grep -i "LnkCap\|LnkSta"
```
- LnkCap: Maximum supported speed and width.
- LnkSta: Current operating speed and width.
Interpret Output:
- 2.5 GT/s = PCIe Gen 1
- 5 GT/s = PCIe Gen 2
- 8 GT/s = PCIe Gen 3
- 16 GT/s = PCIe Gen 4
- Width (e.g., x16, x4) indicates lane count.

Identify the device the system booted from.

lsblk -no pkname $(findmnt -n / | awk '{ print $2 }')

Sometimes a USB device gets stuck and needs a reset without rebooting.

Identify the Controller: List USB controllers and find the one you need to reset.
```
lspci | grep USB
```
Note the ID (e.g., 00:14.0).

Reset: Unbind and rebind the driver. Replace 0000:00:14.0 with your controller's full ID.

echo -n "0000:00:14.0" | sudo tee /sys/bus/pci/drivers/xhci_hcd/unbind
echo -n "0000:00:14.0" | sudo tee /sys/bus/pci/drivers/xhci_hcd/bind

Check the BIOS version.

sudo dmidecode -s bios-version