On-keyboard LCD support. Details within.

Nondysjunction · n00b Joined: 18 Jun 2005 Posts: 6 Location: Kitchener, Ont

The logitech G15 keyboard is an interesting piece of technology. It features a volume knob, multimedia keys, a backlit keyboard, and configurable macro keys, not to mention an LCD display built right into the keyboard.

I have got mostly everything working, except the LCD, and I was wondering if the kernel-level USB-based LCD support might work for this. On my system, the support is embodied by the kernel module usblcd. I am running on 2.6.14-gentoo-r3 currently.

If anyone had any resources related to small-scale LCDs under Linux or the usblcd kernel support, I would greatly appreciate any input.

Edit: I do realize that is not the purpose of the usblcd kernel support. However; maybe this may work?

Thank you for your time, cheers.

porsche08 · n00b Joined: 25 Mar 2005 Posts: 4

I'm wondering if you were able to get macros working. I just bought one of these, but haven't hooked it up to my linux box yet. All I'm really interested in is using the G keys speed up programming a bit. For example, hitting G1 drops an if / else statement into my code.

Ryan

nosenseofhumor1 · Tux's lil' helper Joined: 04 May 2005 Posts: 146

i got one too, and its pretty sweet but drivers make a world of difference.

i have been doing some research, and i have found some interesting tools. i am not a device programmer though, so instead of taking a crack at this myself i would like to share what i have found with you folks and see if anybody makes ground on this freakin thing.

first of all, its a good idea to get a windows box and install USB snoopy on it http://www.wingmanteam.com/usbsnoopy/
using USB snoopy you can listen to the transmission between the bus and device. Filter through the nonsense and find sent messages that seem to occur during image changes on the LCD.

next use the usb skel driver (drivers/usb/usb-skeleton.c) in the kernel source tree for a template. i dont know how this is accomplished, but the fops and minor variables in the declaration of the driver can be used to register your new driver with a TTY subsystem (!!).

of course then you have to write in functions for register/deregister and whatever other standard usb driver requirements are out there. but if you can register this thing with a tty subsystem, talking to the LCD in userspace would be cake!

...that doesnt help at all does it?

nomenquis · n00b Joined: 30 Mar 2005 Posts: 22

Hi,

I started writing a driver for this one. It seems to work pretty well.

http://www.waug.at/g15lcd/

Basically you have to patch your kernel a little bit (nothing dangerous though) and then compile a userspace app with libusb which will print text to the screen. The code for drawing pixels is already in there, so just be creative

Also I'll put a more advanced (smaller / better font etc) version up soon.

Oh, and i hope no one minds the spelling, this keyboard is strange to type on

kind regards

nosenseofhumor1 · Tux's lil' helper Joined: 04 May 2005 Posts: 146

nice work! im a little confused about something though; in one of the images on your page i can barely make out that you are pipeing "hello world" into a file in /var... did i miss something?

nomenquis · n00b Joined: 30 Mar 2005 Posts: 22

nosenseofhumor1 · Tux's lil' helper Joined: 04 May 2005 Posts: 146

wow, good trick! i have a few more questions though; are you looping the "display stdin" because the LCD requires that you are constantly sending data to it or it will clear the display, or because there wasnt a better way to watch it for changes and the loop's load is rather insignificant?

also,

nomenquis · n00b Joined: 30 Mar 2005 Posts: 22

nomenquis · n00b Joined: 30 Mar 2005 Posts: 22

Ok, I've updated the page (http://www.waug.at/g15lcd/) with a newer version.

You now don't need any fifo helpers anymore, the program does it itself. Also you can have three different fonts now. As another bonus the ability to directly draw pictures (simply set active / inactive pixels) was added.

kind regards

nosenseofhumor1 · Tux's lil' helper Joined: 04 May 2005 Posts: 146

ooooooooooo

hey, youre one hell of a programmer! thanks, you are a valuable asset to the community!

nomenquis · n00b Joined: 30 Mar 2005 Posts: 22

nosenseofhumor1 · Tux's lil' helper Joined: 04 May 2005 Posts: 146

not yet, since im going to have to patch my kernel i wanted to make a few tweaks on my menuconfig first... in the next couple of days i should have it going

holycow · n00b Joined: 04 Jul 2005 Posts: 29

Man, am I glad I found this thread. You've done some outstanding work.

I got my g15 keyboard a couple days ago and have been looking for ways to use it's capability under Linux. Your patch and utility open the door for using the lcd.

I patched my 2.6.15 kernel and got it going without any issues. The g15lcd util compiled fine and I was putting text on the lcd in no time at all. I like the image support you've added too.

I will say that having to format the text lines to a single line of quoted text is a bit awkward, but works. Converting images to the "0" and "1" format is also a bit awkward, but doable. I'll have to write a conversion utility for this.

Now, if only the G-keys worked...

If you haven't yet, check out http://phyreskull.ithium.net/g15wiki/wiki/Main_Page. Some good work going on there too.

Thanks!

nomenquis · n00b Joined: 30 Mar 2005 Posts: 22

nomenquis · n00b Joined: 30 Mar 2005 Posts: 22

Version 0.3 is on the homepage now ( http://waug.at/g15lcd/ )
The only change is that you do not need the kernel patch anymore. If you do have it applied already you do not need to recompile your kernel, it will work even with the patch applied.

Edit: please give me some feedback if this new version works for you without the kernel patch.

kind regards

nosenseofhumor1 · Tux's lil' helper Joined: 04 May 2005 Posts: 146

let it be known, it works!
good job! Amazing!

nomenquis · n00b Joined: 30 Mar 2005 Posts: 22

nosenseofhumor1 · Tux's lil' helper Joined: 04 May 2005 Posts: 146

why not attack it a similar way? eat the button presses into a buffer that feeds a function in an infinate loop?

nomenquis · n00b Joined: 30 Mar 2005 Posts: 22

nomenquis · n00b Joined: 30 Mar 2005 Posts: 22

Would anyone have windows here?

I'm trying to figure out the behaviour of the keys but they're actually quite strange and someone with the logitech driver on windows could help me a great deal.

.) Is it possible to press more than 5 g keys at once in windows? I'd like to know if thats possible. What _should_ happen is that if you've already pressed 5 keys then pressing a 6th key will do _nothing_ at all.
.) The M and "L" (the small ones below the display) do not actually have a state (pressed or not pressed) but rather just send press events. This means that for instance there should be no "repeat key" function for these keys. Also it should make no difference if one key is pressed when you press a second key.

Edit: Also the M and L keys seem to only send an event when they are released. So, pressing and holding any of these keys should not have any effekt until you release the key
kind regards

nomenquis · n00b Joined: 30 Mar 2005 Posts: 22

I really do like posting a lot

Aw, version 1.0 is online now. All the G M and L keys work now. Keypresses are send to the kernel which will pass them down the normal keyboard chain. This means that if you run g15lcd and press G13 or so then your X server (if your're running X, otherwise the console) will get the keypress. This is 100% compatible with the gnome keyboard shortcuts for instance. Also one could hook the input chain and react to this events to do some more advanced stuff.

This version will require you to compile a special kernel module (userspace input helper) which is included with vanilla kernel (so no patches necessary). Since v1.0 will refuse to start without the uinput stuff I've also left the old souce on the page in case you only want to display something.

Also note that g15lcd never exists anymore, so echo "foobar" | g15lcd is a pretty bad idea. Rather really create a pipe and use it.

kind regards Philip

Nondysjunction · n00b Joined: 18 Jun 2005 Posts: 6 Location: Kitchener, Ont

I am currently working on an id3-tag displaying script based on the techniques associated with this post. Thank you all for responding to my initial post.

I do have an inquiry to make, though. When refreshing the lcd, the logitech logo that is present by default will flash momentarily. I was wondering if there was a way to make the transition more smooth. Please note I am still using g15lcd.

If anyone is interested, the script I am writing is written in php, and currently supports single-line scrolling output, but will soon support multi-line output. Essentially, there is a pre-text which stays constant, such as an identifier for what is scrolling, and to the right is the scrolling contiguous looping text. Configurable scroll-rate is available. I will make this available as soon as I deem it to be of high enough quality to unleash upon the world.

nosenseofhumor1 · Tux's lil' helper Joined: 04 May 2005 Posts: 146

use the pipe to file method

nomenquis · n00b Joined: 30 Mar 2005 Posts: 22

nomenquis · n00b Joined: 30 Mar 2005 Posts: 22