TVTime works for main user, but not for 2nd user...
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TVTime works for main user, but not for 2nd user...
Hi all,
I am using Ubuntu Feisty, i386. I successfully watch TV with TVTime, from my tv-card. That is from my own user account.
Now I created a user account for my wife, with all the user's privileges enables (audio, video etc...), but whenever I open TVTime from her account, it's a blue screen with this message : "Permission denied, cannot open capture device /dev/video0"
Just a precision, I also multiboot Ubuntu on that box with Fedora 7 & PCLinuxOS 2007, and don't have any such problem in those other systems.
I am very curious to know how to solve that problem, and learn a new trick.
Don't hesitate to give me an idea...
Thank you all in advance for your time and for your help.
but whenever I open TVTime from her account, it's a blue screen with this message : "Permission denied, cannot open capture device /dev/video0"
From the error message, it sounds like it is an issue with the ownership and/or permissions on /dev/video0.
Use the command ls -l /dev/video0 to examine these. You might find the solution is as easy as making your wife a member of another group (remember she has to log out and log back in for the change to take effect), or you might actually have to change the ownership/permissions on that device. I don't know if I can help with the last since I am not yet very familiar with udev
Thank you, Blackhole54, as I experimented what you suggested, and it works now.
What I did was simply in terminal to "sudo nautilus", then i went to /dev/video0, right-clicked, opened "Properties", and on "Permissions", I chose "read & write", and enabled "open as a program".
Just for information, what you did was give everybody read, write, and execute permissions to this device. Since this is pretty much a private computer that is OK. On a more public computer, if you were concerned about security you could turn off the permissions for "other", and then only users who were members of the video group could use it. Also, since you were able to use it from your account before you changed things, I suspect you do not need the execute bit set. Finally, I wonder if your wife really was a member of the video group. When you are logged into an account, you can check the groups thatr user is in by typing groups.
There is a saying "if it ain't broke, don't fix it" -- so perhaps you just want to leave things as they are. Or to "learn so new tricks" you could play a bit more with permissions as I have suggested.
I am looking for a way to make the permissions permanent...
The change is permissions for the device /dev/video0 is probably managed by some wretched HAL or hotplug or udev or similar daemon that runs at boot and creates /dev/video with those permissions. Rather than mess with all that, do the "proper" thing, and just add wife to the group video like this:
sudo useradd -g video wifesusername Edit Nope, I got this wrong, the command should be:
sudo usermod -aG video wifesusername see below./Edit
Then the TV should work. Even after a reboot!
Edit blackhole54 suggested this at the start of this thread - just do it!
martin@spc1:~$ groups
martin adm dialout fax cdrom floppy tape audio dip video plugdev scanner netdev lpadmin powerdev admin fuse
Am I correct that you are user martin? If so, run the groups command from your wife's account and verify that she is a member of the video group. Remember, if you add your wife to this group as tredegar explained, then you (she) must log out of the account and back in before the changed takes effect.
Quote:
I am looking for a way to make the permissions permanent...
I believe that those permissions are controlled by udev. There are configuration files that control this (perhaps under /etc/udev?), but as I have indicated earlier, I have not yet climbed that learning curve. You should be able to find info on the Internet about how to do it. You can probably find something by searching Linux Questions.
Make sure to include the "a" or else you will delete all of the existing groups she is in. I gave you the man page reference because I have never done it this way -- I have always directly edited the /etc/group file. If you decide to directly edit the file, make sure you first make a backup copy of the existing file so you can go back if you make a mistake. (It is always a good idea to make a backup copy of any configuration file before you edit it. Particularly while you are still learning what you are doing.)
I should have read tredegar's post a little more carefully. The command he gave you adds a new user account rather than modifying an existing user's account.
I should have read tredegar's post a little more carefully. The command he gave you adds a new user account rather than modifying an existing user's account.
Oops. Sorry. Pleased the problem is fixed at last! I've edited my post above to point out my error.
we've all had days like this! You changed from -g to -G (which I eventually spotted, but for brevity I didn't mention earlier), but you still show the command to add a user account rather than the command to modify an exisiting account. (I am not trying to be picky here. I am just trying to look out for the future lost souls who are trying to solve their problems using this thread. Yeah, I've been that confused, lost soul too!)
EDIT: And now everything about this thread seems to have be wrapped up and squared away nicely!
Last edited by blackhole54; 06-30-2007 at 11:27 AM.
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