handyfloss

Last friday I wrote about how to install a Huawei E220 modem under MacOSX. Today I will write the corresponding HowTo for Linux.

Usually installation of hardware with non-free drivers is a bit more difficult in Linux than in MacOS and Windows, because the drivers are only made for the latter two. However the E220 is well supported by the Linux kernel (starting at 2.6.20, apparently), so we only need to tweak some configuration files.

1 – Make the system see it properly

The Huawei E220 is a dual machine: apart from being a modem, it is also an USB flash device, with some space to save the Mac/Windows drivers, so that it will “autoinstall” when plugging it under those OSs.

This adds a small level of difficulty, because we have to make sure that the OS sees it as a modem, not as a storage device. In principle the command dmesg (or the file /var/log/messages) will tell us about it. However, I have had it work when dmesg would say that it was a storage device!

The short story is that some [[Kernel (computer science)|kernel modules]] must be loaded, and some others unloaded, when you plug the device. Needed modules: option, usbserial, ppp_async. Must not be present: airprime. In my case usb_storage made no harm, some people say you should unload it. For airprime not to be automatically loaded, put it in some [[Modprobe#Blacklist|blacklist]] file in /etc/modprobe.d/. I decided to add the following line to /etc/modprobe.d/blacklist-modem:

You can ensure the required modules are loaded by taking advantage of [[udev]], but it is not really necessary (in my case it wasn’t). udev can also give you a consistent name for the modem. For me the relevant device was always /dev/ttyUSB0, but you can make it /dev/huawei if you will. For that, you can put the following optional rules in a file in /etc/udev/rules.d/ (for example create 55-huawei.rules):

Two notes: the strings in idProduct and idVendor are obtained running the command lsusb when the modem is plugged. It will show something like:

This is a very neat trick for any USB device we want to manage with udev. The second note is that [[kppp]] (see later) only allows to choose a modem device from a list. If you make the modem be /dev/huawei, you will not be able to use kppp, since that device won’t appear in the list.

2 – Configure wvdial / kppp

You can make use of programs such as [[wvdial]] or [[kppp]] to make the actual connection. I use kppp myself, but that’s up to you (wvdial is apparently more flexible).

wvdial

To use it you have to create a /etc/wvdial.conf file. You can achieve this by running wvdialconf as root, or editing the file by hand, if you are brave.

For me, the output of wvdialconf yielded:

And my current /etc/wvdial.conf looks as follows:

In bold, the relevant user-provided settings. In italics, some items in which you can put whatever, because it doesn’t seem to make a difference.

To connect, run wvdial simyo (or whatever you put in the “[Dialer xxx]” setting above), in the command line. To terminate, Ctrl+C.

kppp

This is the one I use. To open the config/run dialog, run kppp (you can do this as user). There you will have to configure two things: the account and the modem. By pressing “Configure” you will be presented with a window with four tabs. In the first one you will create a new account, in which the relevant data is:

• Phone number: *99#
• Authentication: PAP/CHAP
• Callback type: none

In the second tab you will configure the modem:

• Modem device: /dev/ttyUSB0
• Flow control: Hardware
• Line termination: CR/LF
• Connection speed: 921600

Please note that those are parameters that work for me. I can not assure that they are the “correct” ones. I have player around with different values, and many times the modem would work all the same with different settings. If you find some error in my setup, please tell me :^)

It is common to hear that recent advances in the Linux desktop, such as [[Compiz Fusion]], are more of a fancy but useless aesthetic contribution to the desktop. While it may be true for many of the CF features, it is no less true that you never know when a given effect will turn out to be useful.

In this post I want to praise the Enhanced Zoom Desktop plugin. It turned out to be of great use for me in the following situation. I wanted to run [[Diablo II]] in my laptop (yes, it runs in Linux, under Wine). The native resolution of the program (640×480 or 800×600) is lower than that of my screen (1280×800), so I have two options: to execute it in windowed mode, or fullscreen. In windowed mode the window occupies less than 2/3 of the 13.3″ screen, wasting space and making it unnecessarily small. Fullscreen mode seems to be better, but it isn’t. Since the width/height ratio is smaller for Diablo than for the screen, the former will be stretched horizontally, distorting the images (everything looks more squat). Fullscreen mode also gave me other problems, like crashing more easily when alt-tabbing.

Here is where the zooming of Compiz Fusion comes in handy. Apart from an arbitrary zoom (using the mouse wheel while pressing the Super key, a.k.a. windows key), there is a handy shortcut (Super+r) that zooms up to the point of the screen under the cursor occupying the whole screen. When zooming, the movement of the mouse makes the zooming “window” to move around, showing different parts of the desktop. To avoid it (clearly unwanted if we want to stay inside the Diablo window), we have another shortcut: Super+l. This shortcut toggles on and off the “zooming lens follows the mouse” movement.

So now, if I want to play Diablo I open it in windowed mode, then put the cursor inside the window, then hit Super+r, then Super+l, and I have a Diablo window as big as possible to fit in my screen, preserving height/width ratio, and keeping the mouse inside the window.