USB setup

USB setup

1. USB-FS (Full-Speed) memory size

By default Ubuntu sets the USB-FS memory size to 16Mb for USB devices. In the context of transferring a high resolution image, it's not enough... But there is a way to gain access to a higher amount of RAM for buffering.

There is a permanent way and a temporary way to do it:

Permanent way

In /etc/default/grub text file, modify:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"  

to

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash usbcore.usbfs_memory_mb=1000"

Update grub :

$ sudo update-grub

Reboot computer

Temporary way

Enter this command in a terminal :

$ sudo sh -c 'echo 1000 > /sys/module/usbcore/parameters/usbfs_memory_mb'

To confirm the change has been done, type :

$ cat /sys/module/usbcore/parameters/usbfs_memory_mb

Documentation

You can find more info on USB-FS here : https://www.flir.com/support-center/iis/machine-vision/application-note/understanding-usbfs-on-linux/