Permission to use webcam?

[JMO]

I have a ZC0301 webcam connected to a USB port. As root, I can use it without any kind of problems, but no user on my machine is able to "detect" the camera.

Is this a permission problem?
How can I solve it?

[Peacepunk]

If you look around, you'll find answer that doesn't work for Fedora10, with eventually a dangerous one about udev rules that could hang your system!

http://forums.fedoraforum.org/showthread.php?t=211176
http://forums.fedoraforum.org/showthread.php?t=177859
http://forums.fedoraforum.org/showthread.php?t=94775
http://forums.fedoraforum.org/showpo...19&postcount=4

Since F10 hasn't got 50-udev.rules anymore, and that the solution here:
http://www.linuxquestions.org/questi...sions.-701934/
looks the same but Fedora rc.d structure of file isn't standard & you can't just apply the solution to all usbfs sytem,

I decided to treat the webcam as a complete alien, since that's how Fedora is taking it anyway;
Solution pumped from here:
http://forums.nxtasy.org/index.php?s...23&#entry16723

&& simplified here:
http://wiki.zenerves.net/index.php/Nxt::usb

It's the recipe to hook the NXT Intelligent Brick from the LEGO MindStorm robotics system to your computer via USB and a special set of rules.
[FYI: http://mindstorms.lego.com ]

If I was able to connect to something as utterly unknown to my system, as user, sure I can find there a recipe to hook this freaking webcam, no?

Follow me, at your own risks: I consider this a poor hack, but it works, including after Suspend/Resume, which was my issue since a simple chmod a+rw /dev/Video0 in the /etc/rc.d/rc.local file was enough to get proper permissions upon start-up but not to keep them after suspend/resume:

!ALL done as root!


1. Plug cam (if not integrated, duh!), open terminal, as root:

lsusb

returns a list of plugged devices, my laptop returns:

Bus 002 Device 002: ID 174f:6a33 Syntek Web Cam - Asus F3SA, F9J, F9S

What's important here today is 174f, 6a33 and Syntek; we'll need them later: write it down, or, simply, open another root terminal to continue, keeping these info at hand for later.

The ID Vendor is the first number, here it is 174f
The ID Model is the second number, here it is 6a33
The Name of Product here is the one we'll use as name for the special Group Syntek


2. Terminal job again, let's create the needed group and link it to the user(s), as root:

groupadd <YourWebcamNameHere>
usermod --append --groups <YourWebcamNameHere> <Your User Name>

It is probably sane to add root and any other user of this computer's webcam to the group by repeating the procedure above.

Obviously, I did usermod --append --groups Syntek f10 where Syntek is the name of my camera and the special group created on purpose here and f10 is the username we use on this Fedora10 laptop.

You can check this with, as root ever:

id <Your User Name> -Gn

Which should return the names of the group your user name belongs to. Unless this is properly set up, there is no need to keep going further;
Notice that Fedora/Gnome has a GUI tool to manage that, one may feel more comfortable with: System->Administration->Users And Group. (You can at least use this to check if your user is registered with your new group)


3. Now as root, again, create with a text editor (gedit or kate or mousepad or VIM), a file called

45-<YourWebcamNameHere>.rules

insert the following in the file; don't forget to ADAPT to your webcam ID vendor, ID product and Name, especially since it is your Group Name too, and we need to attach this device to that group once and for all:

You can do:

gedit /etc/udev/rules.d/45-<YourWebcamNameHere>.rules

or, if you know VIM,

vim /etc/udev/rules.d/45-<YourWebcamNameHere>.rules

Contents of file to be the new rule:

SUBSYSTEM=="usb_device", ACTION=="add",
SYSFS{idVendor}=="<YourID VendorHere>" ,
SYSFS{idProduct}=="<YourID ModelHere>",
SYMLINK+="<YourWebcamNameHere>-%k",
GROUP="<YourWebcamNameHere>",
MODE="666"

What I had to do in real life (as root, from the /etc/udev/rules.d folder too):

vim /etc/udev/rules.d/45-Syntek.rules

So for your reference mine look like this:

SUBSYSTEM=="usb_device", ACTION=="add",
SYSFS{idVendor}=="174f" ,
SYSFS{idProduct}=="6a33",
SYMLINK+="Syntek-%k",
GROUP="Syntek",
MODE="666"

Check your new file called 45-<YourWebcamNameHere>.rules. You can do so with:

less /etc/udev/rules.d/45-<YourWebcamNameHere>.rules /etc/udev/rules.d/

Which should print the contents of your new file in the terminal.

What's in this file anyway?

This file is read upon startup, and it takes action in a precise way (that is why it is not dangerous, because it only speaks to one device):

SUBSYSTEM=="usb_device", ACTION=="add", -- we are speaking USB, and specifically what to do with it
SYSFS{idVendor}=="174f" , -- This is the brand,
SYSFS{idProduct}=="6a33", -- This is the model, these are unique descriptor to hook to the target,
SYMLINK+="Syntek-%k", -- That is to Link the actual device to the proper /dev/ tree where I'll have permissions to read,
GROUP="Syntek", -- This is my groupname with special permissions for me to access the webcam,
MODE="666" -- The 666 is the permissions as Read/Write for everybody;

The whole lot is to me just self-explanatory gibberish that I copied and pasted, successfully over 3 different computers to gain access to my Lego Mindstorms Brick, so I know the above procedure isn't dangerous & you know I still play with Legos .


You can check perms of your device after full reboot with:

ls -l /dev/vide*

and you should have tons of /dev/webcam-something if you do

ls /dev/<Your Webcam Name Here Minus The Last Letter>*

Regarding this hack, I say it's safe, but that's only me saying so, a simple user with very few posts, so if you don't understand this, DON'T DO IT! Never trust no-one that tries to trick you into firing up scripts or command-lines inputs in a terminal blindly.

Review the above, ask others, make up your mind. A said earlier, it's a poor hack that is targeted at enabling one single particular, obviously alien, device to the Linux usb subsytem. If the system wasn't broke in the first place, we wouldn't need to fix it so poorly with such lack of skills.

I say it's safe, it works. You shouldn't believe what anybody says

Cheers

Jean-Philippe

[JMO]

I'm not even using Fedora anymore (damned Mandriva!), but when I come back with the eleventh version, this will be very useful. Thanks a lot for your answer!

[Peacepunk]

The fact that your post stayed unanswered for so long says a bad lot about this place I'm afraid.

[As it happens, I am on Slackware 12.2 now - Don't upgrade unless really, badly needed - My Logitech QuickCam Communicate STX was perfect with GSPCA on 2.6.23 (self-compile), then they integrated GSPCA to the official kernel and it doesn't work anymore! I want to bite somebody!]




Peace. Love, and ZEN computing to you all.
Jean-Philippe.

[Penguins007]

I followed you process... But the red line that I am stuck at...

If you look around, you'll find answer that doesn't work for Fedora10, with eventually a dangerous one about udev rules that could hang your system!

http://forums.fedoraforum.org/showthread.php?t=211176
http://forums.fedoraforum.org/showthread.php?t=177859
http://forums.fedoraforum.org/showthread.php?t=94775
http://forums.fedoraforum.org/showpo...19&postcount=4

Since F10 hasn't got 50-udev.rules anymore, and that the solution here:
http://www.linuxquestions.org/questi...sions.-701934/
looks the same but Fedora rc.d structure of file isn't standard & you can't just apply the solution to all usbfs sytem,

I decided to treat the webcam as a complete alien, since that's how Fedora is taking it anyway;
Solution pumped from here:
http://forums.nxtasy.org/index.php?s...23&#entry16723

&& simplified here:
http://wiki.zenerves.net/index.php/Nxt::usb

It's the recipe to hook the NXT Intelligent Brick from the LEGO MindStorm robotics system to your computer via USB and a special set of rules.
[FYI: http://mindstorms.lego.com ]

If I was able to connect to something as utterly unknown to my system, as user, sure I can find there a recipe to hook this freaking webcam, no?

Follow me, at your own risks: I consider this a poor hack, but it works, including after Suspend/Resume, which was my issue since a simple chmod a+rw /dev/Video0 in the /etc/rc.d/rc.local file was enough to get proper permissions upon start-up but not to keep them after suspend/resume:

!ALL done as root!

1. Plug cam (if not integrated, duh!), open terminal, as root:



returns a list of plugged devices, my laptop returns:


What's important here today is 174f, 6a33 and Syntek; we'll need them later: write it down, or, simply, open another root terminal to continue, keeping these info at hand for later.

The ID Vendor is the first number, here it is 174f
The ID Model is the second number, here it is 6a33
The Name of Product here is the one we'll use as name for the special Group Syntek

2. Use System>Administration>Users & Groups to add a group by the name of your webcam (It was Syntek then for me); add yourself and any needed user + root to this new group; close the User & Group application once finished. Double-check that your basic, ordinary user is a member of the <YourWebcamNameHere> new group you just created.

3. Move to /etc/udev/rules.d/ and create there a file called 45-<YourWebcamNameHere>.rules. You can do so with: (it was, obviously, 45-Syntek.rules on my laptop)


insert the following in the file; don't forget to ADAPT to your webcam ID vendor, ID product and Name, especially since it is your Group Name too, and we need to attach this device to that group once and for all:


So for your reference mine look like this:


The 666 is the permissions as Read/Write for everybody; the rest is just self-explanatory gibberish that I copied and pasted, successfully over 3 different computers to gain access to my Lego Mindstorms Brick, so I know the above procedure isn't dangerous & you know I still play with Legos .

You can check perms with:



and you should have tons of /dev/webcam-something if you do




Regarding this hack, I say it's safe, but that's only me saying so, a simple user with very few posts, so if you don't understand this, DON'T DO IT! Never trust no-one that tries to trick you into firing up scripts or command-lines inputs in a terminal blindly.

Review the above, ask others, make up your mind. A said earlier, it's a poor hack that is targeted at enabling one single particular, obviously alien, device to the Linux usb subsytem. If the system wasn't broke in the first place, we wouldn't need to fix it so poorly with such lack of skills.

I say it's safe, it works. You shouldn't believe what anybody says

Cheers

Jean-Philippe

The red line, I click... System > Administration > Users & Groups.
Click "Add Group" the enter <YourWebcamNameHere> and leave unmark (specify group ID manually)

You mentioned double check, ordinary user is a member of the <YourWebcamNameHere> new group you just created. Is my user section show up after created new group? I showed only one ??

The purple one... I believe i didnt follow the instruction. When you said to create a file to 45-webcamname.rules, but it showed a folder instead?? Will you please tell me how to make file not folder??

Last thing...
When I go /dev/webcam, it come up

bash: /dev/webcam: No such file or directory

when I am on root or without root, I typed webcam, but I got same error...

I am on FC 10...

[Peacepunk]

[EDIT: Extensively rewrote the main post, please try again... before posting again!]

Updated to CLI mode of managing/adding Group and User.

Updated the "create file in /etc/udev/rules.d" part for more clarity too


Added content description of the udev script;

================================================== ============================

The purple one... I believe i didnt follow the instruction. When you said to create a file to 45-webcamname.rules, but it showed a folder instead?? Will you please tell me how to make file not folder??

One way is, terminal as root:

gedit /etc/udev/rules.d/45-<YourWebcamNameHere>.rules

Will give you a traditional text editor where it will be easy for you to copy and paste my sample file and to adapt to your needs.

if needed,
Please post the result of lsusb AS ROOT,

Please post the output of id <your username here> AS USER.
Please post the output of id <your username here> -Gn AS ROOT.

I will be able to help more.

The latest problems are because the preliminary steps where not completed.

Cheers.

[EDIT: Extensively rewrote the main post, please try again... before posting again!]

[Penguins007]

I will get back with result in the evening... One thing I wanted to ensure that my webcam and laptop are communication well...

when I enter lsusb, it responds... however, when I enter /dev/video0, it said not found?? I wonder what difference between those two??

After I edit to give a permiission, will /dev/video0 show up??

Thanks!

[Peacepunk]

I can help you be sure you can access the device, but if it is located in a non-standard location you may have to ask/check elsewhere, preferably with a new thread, after we sorted the permissions out.

You can't just "go" for /dev/video0 or "do" or /dev/video0; your proper checking method is

ls -l /dev/vide*

Which literally means LiSt -Long, detailed /dev/videANYTHING - But there is no sense in doing that as long as you haven't succeeded in the above and fully rebooted your system!

Cheers.

[Penguins007]

I followed you steps smoothly after full reboot (shutdown) and wait 5 minutes to pray it will work... After boot up, and tested ls - /dev/vide*... The outcome is failed...

$ ls -l /dev/vide*
ls: cannot access /dev/vide*: No such file or directory

Worse case, my internet and email are not working... I can see my wireless is running... but can't do firefox or emails

So, I had to remove 45-Microsoft-rules... Then reboot, and my internet and emails are restored.. whew..

My webcam is Microsoft VX-3000...

[Peacepunk]

?? Doesn't make sense ??

It is NOT ls - /dev/vide*... Once and for all it is ls -l /dev/vide*

Please post:

result of lsusb AS ROOT,
output of id <your username here> AS USER.
output of id <your username here> -Gn AS ROOT.
output of ls -l /ect/udev/rules.d/45-Microsoft.rules
output of less /etc/udev/rules.d/Microsoft.rules AS ROOT.

Your 45-Microsoft.rules should look as follow:

(ADAPT TO SUIT YOUR SYSTEM!)

SUBSYSTEM=="usb_device", ACTION=="add",
SYSFS{idVendor}=="<YourID VendorHere>" ,
SYSFS{idProduct}=="<YourID ModelHere>",
SYMLINK+="Microsoft-%k",
GROUP="Microsoft",
MODE="666"

[But you of course could have chosen another name this ne looks silly]

[Penguins007]

Ok, let me check again at home, as right now, my laptop unable to connect internet and email... Right now, I am at work and will be home about before earlier evening...

As Product Name... Ha... I will change from M$ to be more creative since i followed your instruction and didn't think of it ha... One more thing, I wanted to be ensure that I input correct information... The step #2:

2. Terminal job again, let's create the needed group and link it to the user(s), as root:

groupadd <YourWebcamNameHere>
usermod --append --groups <YourWebcamNameHere> <Your User Name>

It is probably sane to add root and any other user of this computer's webcam to the group by repeating the procedure above.

Obviously, I did usermod --append --groups Syntek f10 where Syntek is the name of my camera and the special group created on purpose here and f10 is the username we use on this Fedora10 laptop.

You can check this with, as root ever:

id <Your User Name> -Gn

So, username is what I can make up for identify me as user on this laptop? because i am only one that using my laptop without any addition users or guests... I will be right back with post information...

Thanks

[Peacepunk]

So, username is what I can make up for identify me as user on this laptop?

yes, that is right. sometimes username is not what login screen shows; we need here the linux username you gave when you installed the system; do AS USER in a terminal, if you are not sure:

users

It will show the name of anybody logged to your system; if there is only you then it is easy to get your username.

It also usually shows in a terminal, showing [username@machine ~] at the cursor position - on my laptop, the user is currently f10 (just because we use Fedora10, that's all!) and the machine is called F9E (because it is an Asus F9E, duh!). The names I use are not important, only you need to provide the good information for others to help.

[Penguins007]

output of id username as user:

uid=500(dmzeplin) gid=500(dmzeplin) groups=500(dmzeplin),501(LaserVideo)

output of id username I id username -Gn

dmzeplin LaserVideo

So, I continue input information in editor and saved. The outcome:

less /etc/udev/rules/.d/45-LaserVideo.rules /etc/udev/rules.d/

UBSYSTEM=="usb_device", ACTION=="add",
SYSFS{idVendor}=="045e",
SYSFS{idProduct}=="00f5",
SYMLINK+="LaserVideo-%k",
GROUP="LaserVideo",
MODE="666"

[Penguins007]

After reboot.....

~] $ ls -l /dev/vide*

Output: ls: cannot access /dev/vide*: No such file or directory

~ ] # ls -l /dev/vide*

Output: ls: cannot access /dev/vide*: No such file or directory

[Peacepunk]

do:

ls -l /dev/LaserVide*

do:

lsmod|grep video

lsmod|grep gspca