I have a bluetooth remote that is paired with my linux box, when active, this remote is visible at /dev/input/event13.
I have a small C program that open this device and read directly from it, which works fine.
Now, my problem is that this remote goes to sleep after a few minutes of inactivity and /dev/input/event13 disappears. It reappears as soon as I press a key on my remote.
I put the output of udevadm here: https://gist.github.com/9fff2f0d7edef1050060.
I use the following code (small ruby ext I wrote), to read from the device: https://gist.github.com/b403d538eb6a8627e2bd.
I thought of writing an udev rule that would start my program when my remote is added and stop it when it is removed. I read the udev documentation, but I couldn't figure it out how to do it. I'm open for suggestion.
After some digging and a lot of frustration I did the following:
I put into /etc/udev/rules.d/99-rmote.rules
KERNEL=="event*", SUBSYSTEM=="input", ACTION=="add|remove", ATTRS{name}=="TiVo Keyboard Remote", RUN+="/home/kuon/handleConnect.rb"
And in handleConnect.rb I check the ACTION environment variable and I start/stop my daemon accordingly. Quite simple in the end and it works well.
Related
Would anyone know how to disable the virtual terminals in linux? I am using Yocto, Morty version on an i.MX6 processor. Even though our base distribution is Yocto, unfortunately we have diverged from building it with recipes, so this is more of a straight linux question than Yocto…
To give some detail as to my problem: It is for an embedded device that has an HDMI port - when I attach a terminal to the HDMI port it shows the Linux Penguin logo, a getty service and blanks out after 600 seconds. I just want to use the hdmi port as an output with nothing displayed on the output and I want it to stay on all the time.
I have found that the hdmi port maps to /dev/tty1 – when I type: echo “asdfasdf” > /dev/tty1 I see the characters output to the monitor.
Here are a few things I have tried to no avail – a lot of these are not needed if I can figure out how to disable it as a virtual terminal…
• I figured out how to disable the getty service but a cursor still blinks. I don’t even want a cursor to show
• I have tried to disable the display of the penguins by disabling the LOGO in the kernel config parameters - I commented anything with LOGO out:
CONFIG_LOGO=y
CONFIG_LOGO_LINUX_MONO=y
CONFIG_LOGO_LINUX_VGA16=y
CONFIG_LOGO_LINUX_CLUT224=y
To no avail. The logo still shows : .
• The fact that it blanks after 600 seconds is console blanking – I can see it set to 600 in the file: /sys/module/kernel/parameters/consoleblank. When I issue the command: echo -e '\033[9;0]'>/dev/tty1
It sets the console blanking to 0 and wakes the terminal. Being able to wake the console up is limited success but I would like to disable the virtual terminal altogether…
• I tried commenting out any virtual terminal defines in the config file to no avail:
CONFIG_VT=y
CONFIG_VT_CONSOLE=y
CONFIG_VT_CONSOLE_SLEEP=y
CONFIG_HW_CONSOLE=y
CONFIG_VT_HW_CONSOLE_BINDING=y
Everything I have read suggests that /dev/tty1 is a virtual terminal or console. From what I read about the VT option, disabling the CONFIG_VT should do it:
VT — Virtual terminal Say yes here to get support for terminal devices
with display and keyboard devices. These are called "virtual" because
you can run several virtual terminals (also called virtual consoles)
on one physical terminal. You need at least one virtual terminal
device in order to make use of your keyboard and monitor. Therefore,
only people configuring an embedded system would want to say no here
in order to save some memory; the only way to log into such a system
is then via a serial or network connection. Virtual terminals are
useful because, for example, one virtual terminal can display system
messages and warnings, another one can be used for a text-mode user
session, and a third could run an X session, all in parallel.
Switching between virtual terminals is done with certain key
combinations, usually Alt-function key. If you are unsure, say yes, or
else you won't be able to do much with your Linux system.
But for some reason it doesn’t do anything!
• I found this thread; https://askubuntu.com/questions/357039/how-do-i-disable-virtual-consoles-tty1-6 among others, but none are much help since my distribution does not have any of the directories in the solutions offered in this thread or any others I have found. For instance I do not have a /etc/events.d nor do I have a /etc/default/console-setup file nor do I have a /etc/init directory… I imagine the reason for this is that my distribution uses systemd and the solutions are SysV based init maybe?
Disabling the logo or console blanking would not be necessary if I could just figure out how to disable that port as a terminal…
So does anyone have pointers or things I could try? I am relatively new (returning after 10 years - I worked with DNX 10 years ago v2.6 and it seems everything I knew about init is fairly obsolete lol) to linux so I am sure I am missing a lot…
Thanks,
- Chuck
I think I found the answer to my question. This is actually a frame buffer console documented here: Documentation/fb/fbcon.txt. From the documentation:
The framebuffer console (fbcon), as its name implies, is a text
console running on top of the framebuffer device. It has the
functionality of any standard text console driver, such as the VGA
console, with the added features that can be attributed to the
graphical nature of the framebuffer.
Commenting out the line
CONFIG_FRAMEBUFFER_CONSOLE=y
In the configuration file located in /arch/arm/configs will disable it.
Also this part of the documentation shows you how to disable it at runtime:
So, how do we unbind fbcon from the console? Part of the answer is in
Documentation/console/console.txt. To summarize:
Echo a value to the bind file that represents the framebuffer console
driver. So assuming vtcon1 represents fbcon, then:
echo 1 > sys/class/vtconsole/vtcon1/bind - attach framebuffer console
to
console layer echo 0 > sys/class/vtconsole/vtcon1/bind - detach framebuffer console from
console layer
When I issue the echo 0 command, the cursor stops blinking and starts blinking again when I issue the echo 1 command.
I think there is another way of doing it as well by modifying the Yocto build environment by putting the USE_VT="0" in the OpenEmbedded machine config file. The "USE_VT" variable is referenced by the sysvinit-inittab recipe. This answer was given to me from the Yocto Linux mailing list - but I have not tested it since we have diverged from Yocto...
There's quite a bit of information out there on this topic, but for some reason I just can't get it to work. This is on a raspberry pi running the 'DietPi' flavor over the raspian distro, and is perhaps what separates my question from the others.
So I have a GUI application that I wish to launch at boot, after the LXDE session has begun. So I have utilized the following file here:
/etc/xdg/lxsession/LXDE/autostart
and added the line:
#/myapplication
This works, however, it launches multiple instances of this program, and the first one always crashes. This creates problems because there's some competition for resources (IO, files, etc). So what I did was create script file, /myapplication-autostart.sh instead like so:
if pgrep "myapplication" > /dev/null
then
echo "my application is already running"
else
/myapplication
fi
and then changed /etc/xdg/lxsession/LXDE/autostart to #/myapplication-autostart.sh. Now what I find is the program launches once, but the instance crashes. It crashes when it attempts to create a window (opencv imshow). This is strange because the program will also run headless if an X-session is not available, but for some reason it crashes and I do not know where to check why.
Also, to test it wasn't an issue with the script file, I commented everything out except the /myapplication and I have found the script file runs in a continuous loop and every time I close the application it opens back up. I'm not sure why this is either.
I've tried adding a sleep delay in the script and it does not help. For whatever reason, it seems the LXDE autostart script is ran at least 3 times when booting the pi and the circumstances around the first cause the program to crash. Does anybody understand this sequence and behavior of calling this autostart script?
It is also possible to use the XDG standard Autostart - which is independent of the used desktop environment - by placing desktop files at
$XDG_CONFIG_HOME/autostart (by default ~/.config/autostart)
or for system-wide autostarts at $XDG_CONFIG_DIRS/autostart (by default /etc/xdg/autostart).
Such a .desktop-file could look like:
[Desktop Entry]
Type=Application
Version=1.0
Name=JDownloader
Exec=/usr/local/bin/my-application.sh
Categories=Utilities
The specification of desktop-files can be found at freedesktop.org.
Here was the final solution...
/etc/xdg/lxsession/LXDE/autostart added the line:
/myapplication-autostart.sh
and /myapplication-autostart.sh was changed to:
#!/bin/bash
if pgrep "myapplication" > /dev/null
then
echo "my application is already running"
else
if [[ "$DISPLAY" = ":0" ]]
then
/myapplication
fi
fi
I had to write the display variable to file in combination with the errors to file to discover the issue. At login 2 X sessions were created, display ":1" and display ":0", in that sequence. Display ":1" crashed because, although not headless, it was not initialized to a particular resolution and there was some resizing code in my program. Display ":0" was the actual display on the HDMI out and the one I wanted. Really, the conditional check to see if the application isn't necessary but I left it in there to be safe. I could have also left the # on the LXDE autostart file but it got annoying in the cases I wanted to close the application because it'd keep re-opening. Possibly I'll put it back later.
Thanks for the help!
First, some comments about opening several instances of the program: when you use "#" at the beginning of the line on the startup file (ex.: #/myapplication), this requests your system to try to launch the program, but if the program fails to open correctly, then the system will try to open it multiple times until it opens correctly -- if you remove "#" from the line beginning, then the system will only try to open the program once.
Now, to find out why the program is failing, I advise you to add
2> /file/log
to the end of every command on your script. Doing so would append any error message to a log (/file/log), and analyzing those error messages would be key to find out why the program is misbehaving.
One important note: if your program needs root privileges to run, then it will fail when called via /etc/xdg/lxsession/LXDE/autostart, as this method calls programs without elevated permissions.
This is an old thread but I was having problems getting autostart to start all the tasks listed. After many days I concluded there were one or more "invisible" characters that autostart didn't like. So I deleted the lines for the tasks that didn't start and retyped them. That solved the problem!
I think I corrupted the lines because I was editing some of the lines on my Windows computer. It was likely inserting CR with LF or some other stuff. I WILL NEVER EDIT TEXT FOR LINUX USING WINDOWS!
Maybe someone else will hit this problem and this may help them. I don't know where else to put this information.
I'm new to Linux.Yesterday I wrote some Python codes,now I'm using Linux to execute my codes,it may take a few hours. As my Linux is not native,it's a remote server,I use putty to connect to it.
Now ,I want to close putty and go to sleep.But I don't know how to find my process again and reenter it after I wake up and start putty.And also,I wrote some code to print progress rate，next time when I find the process,can I see the print info again?
Run screen, start your programm and close the connection. After logging in again, use screen -r to resume your session.
Alternatively nohup will do the trick.
screen is the best built-in tool that's always available for that, although it gets a bit weird around keyboard shortcuts, some of which sometimes don't work the way you want exactly.
I've found tmux to be much better in terms of usability.
Alternatively. take a look at mosh, which is trying to replace ssh. It's a mobile shell tool from MIT that supports intermittent connectivity, lots of praise there.
I'm using a raspberry pi 2 to show all the video's in a folder. The raspberry automatically boots up (with a generic electric timer) in to console (not the gui) and after it boots it runs a bashscript I found here. This bashscript contains an infinite loop to play all the videos in a folder using omxplayer.
When I boot in to consolemode and manually start the script everything works perfectly. The terminal screen clears, the first video starts, and after it ends there is a second or two of black screen (empty terminal) and the second video starts playing. This is exactly what I want.
However, when I use crontab to start this script (#reboot /path/to/script.sh) the terminal messages stay and it doesn't clear everything between video's.
I've tried creating my own script that first clears everything, and then calls the second script. But this doesn't work.
I'm really really new in this field (but I'm having fun) so any pointers in the right direction would be appreciated!
P.S. I edited the /boot/cmdline.txt file so it doesn't display critical kernal logs as a work-around.
You should not be doing this using cron. You should be changing the inittab so that it runs outside any environment that may be created. See the inittab(5) man page for details. You may also be interested in openvt(1) as well.
Problem:
I have an extra set of top and bottom gnome-panels for a second monitor. When I undock my lenovo Thinkpad (T510), the extra top and bottom panels remain, so I have two on top and two on the bottom. I am currently running a RHEL6/Fedora (x86_64) gnome (2.28.2) instance with xmonad (0.9.1-6.1.el6) set as the window manager, using the xmonad extensions to work within gnome.
Tried:
I've used acpi and found a code for docking and undocking, but when I try to utilize a script I found in this blog post, it gets zero for the call to xrandr. The script works when called on its own from the terminal. I've tried calling a separate looping script in its own thread and it keeps getting zero for the value, long after the screen(s) update(s).
I have figured out how to have a script loop every X seconds and check for a file which is touched into existence in the event of the script getting a zero, then performing the necessary change, but I don't like that approach.
Question:
I'm hoping someone knows a place I can drop a call to the referenced script and have my panels come and go as I would expect without needing to initiate the script manually.
Thanks!
Update: I have added a bounty of 50 (max I can do) for an answer.
Ben
I guess one of the problems listed below occures (or both):
1) looks like your xrandr snippet doesn't return proper values because the $DISPLAY environment variable is not set correctly. Acpi handler script normally runs as a user which is not the user running your current X session. That way xrandr just does not know which $DISPLAY to access.
2) if $DISPLAY is set correctly, the acpid user might still not be able to access your running xsession. You might check whether the script will work over acpi handler, if you execute xhost + as the user who is currently runging the current xsession with $DISPLAY specified in your script. This will disable access control for X. You can reenable it with xhost - again.
Check it, I hope it helps or will at least point you in which direction to dig.