Monthly Archives: September 2015

CSL 300 Mbit/s wifi adapter with Debian 8 Jessie

The CSL 300 Mbit/s wifi adapter is available at Amazon and is an inexpensive wifi USB adapter for Linux. It supports 802.11 b/g/n, WPA2, and has an external antenna adapter.

It identifies as follows with "sudo lsusb":

Bus 003 Device 002: ID 0bda:8172 Realtek Semiconductor Corp. RTL8191SU 802.11n WLAN Adapter

The loaded kernel module is "r8712u" (check with "sudo lsmod | grep r8712u").

To make it work with Debian Jessie, all you need to do is to install the standard Debian package "firmware-realtek". The output in "kern.log" after installing the package and plugging in the USB adapter should look something like this:

Sep 27 13:50:37 computername kernel: [    9.617950] r8712u: module is from the staging directory, the quality is unknown, you have been warned.
Sep 27 13:50:37 computername kernel: [    9.618985] r8712u: Staging version
Sep 27 13:50:37 computername kernel: [    9.619009] r8712u: register rtl8712_netdev_ops to netdev_ops
Sep 27 13:50:37 computername kernel: [    9.619014] usb 4-2: r8712u: USB_SPEED_HIGH with 4 endpoints
Sep 27 13:50:37 computername kernel: [    9.619553] usb 4-2: r8712u: Boot from EFUSE: Autoload OK
Sep 27 13:50:37 computername kernel: [   10.284174] usb 4-2: r8712u: CustomerID = 0x000a
Sep 27 13:50:37 computername kernel: [   10.284178] usb 4-2: r8712u: MAC Address from efuse = 20:ac:3f:b9:b9:b9
Sep 27 13:50:37 computername kernel: [   10.284181] usb 4-2: r8712u: Loading firmware from "rtlwifi/rtl8712u.bin"
Sep 27 13:50:37 computername kernel: [   10.284258] usbcore: registered new interface driver r8712u
Sep 27 13:50:37 computername kernel: [   10.348992] usb 4-2: firmware: direct-loading firmware rtlwifi/rtl8712u.bin

Make imdb work with Google Chrome browser (blank black video)

Recently Google Chrome introduced the ability to activate plugins only after user confirmation. While this is a very good setting to increase your security level (especially for flash plugin), it prevents certain sites to display their content, e.g.

The video window on will stay black, no error message, no way to activate the flash plugin. If you want to make it work, add an exception to the plugin content settings.

Within chrome, go to "Settings" -> "Privacy" -> "Content settings..." -> "Plugins" -> "Manage exceptions..." and add the following to the list of plugin exceptions:

[*.]              allow

Useful ntp server configuration settings

All configuration settings go into /etc/ntp.conf.

Limiting ntp server to one network interface (plus localhost):

interface ignore wildcard
interface listen eth0

Make local hardware clock work as a backup ntp source with high stratum (set it to 0 if local hardware clock is set by some other external time source):

fudge stratum 8

Never give up synchronising even if clock difference is very large:

tinker panic 0

Increase the number of candidate servers (default 3 -> 5) and servers used by the selection algorithm to set the system clock (default 1 -> 2):

tos minclock 5
tos minsane 2