[mythtv-users] Permissions on devices?

[Barry Davis]

try this:
    dd if=/dev/zero of=/dev/dsp0

If this fails straight away then you won't be able to get anywhere with 
an application that needs sound like mythtv. If it works press CtrlC to 
stop it otherwise it will go on for ever.
Seeing as you have devfs and this file exists (/dev/dsp) I'm pretty 
confident that you sound is working.
You can change the ownership of /dev/dsp to yourself using chown 
user:group /dev/dsp, but that will be tempoary, next time you reboot it 
will be recreated with the original ownership.

Did you try adding yourself to the audio group?

Joe Schmidt wrote:

> When I checked out the /etc/devfsd.conf, it appeared to me that 
> /dev/sound/dsp was the one that was set to belong to the audio group! 
> So I went into setup, set it to use that as the audio capture device, 
> and tried out the frontend again. Here's my new errors:
>
> Delaying to next trigger: 22044990
> Delaying to next trigger: 32635596
> Audio buffer overflow, audio data lost!
> Audio buffer overflow, audio data lost!
> Audio buffer overflow, audio data lost!
>
> And when I use /dev/dsp0...
>
> lotus mythtv # mythfrontend
> connecting to backend server: 127.0.0.1:6543
> adding: lotus.njit.edu as a player 1
> adding: lotus.njit.edu as a player 0
> adding: lotus.njit.edu as a player 0
> adding: lotus.njit.edu as a remote ringbuffer
> Changing from None to WatchingLiveTV
> opened vbi device
> Changing from None to WatchingLiveTV
> strange error flushing buffer ...
> Over/underscanning. V: 0.000000, H: 0.000000, XOff: 0, YOff: 0
> Using XV port 61
> Delaying to next trigger: 18049700
> Delaying to next trigger: 19382356
> Delaying to next trigger: 17799915
>
> Barry Davis wrote:
>
>> If its a permission thing with devfs you either need to modify 
>> /etc/devfsd.conf or you need to add you user name to the audio group 
>> in /etc/group. There should be a line which reads "audio:x:17:root" - 
>> change it to "audio:x:17:root,youruser".
>> I think the audio devices get created with permissions 0660 for 
>> groups root and audio when the soundcard module is pulled in.
>> I don't have a soundcard in my work pc anymore so I can't be sure, 
>> but I had it working last year.
>>
>> Joe Schmidt wrote:
>>
>>> Thanks for the reply! I'm using devfs, so maybe that handles 
>>> symbolic links in /dev a bit differently. *shrug*
>>>
>>> I now receive the following errors flooded through my screen when I 
>>> try to watch live TV.
>>>
>>> only read -1 from 4096 bytes from '/dev/dsp'
>>> read audio: File descriptor in bad state
>>> ran out of free AUDIO buffers :-(
>>>
>>> I'm not sure what I'm doing wrong. Maybe I messed up installing ALSA 
>>> somehow? I followed the instructions to the letter (I think..)
>>>
>>> Thanks for the continued help from everyone. :-)
>>>
>>>
>>> Ray Olszewski wrote:
>>>
>>>> At 11:50 PM 5/7/2003 -0400, Joe Schmidt wrote:
>>>> [...]
>>>>
>>>>> Thanks to the advice of someone else on the list, I think I have 
>>>>> my sound card set up properly. However, I receive errors while 
>>>>> trying to watch Live TV, and then exiting from LiveTV:
>>>>> [...]
>>>>>
>>>>> Here are the permissions on the two dvices mentioned:
>>>>> $ ls dsp -l && ls mixer -l
>>>>> lr-xr-xr-x    1 root     audio           9 May  8 11:24 dsp -> 
>>>>> /dev/dsp0
>>>>> lr-xr-xr-x    1 root     root           11 May  8 11:24 mixer -> 
>>>>> /dev/mixer0
>>>>>
>>>>> I tried changing dsp to group audio and making sure I was a member 
>>>>> of audio, but it did not seem to make a difference. (Later, I 
>>>>> noticed that all users have read and execute permissions anyway).
>>>>>
>>>>> How does everyone else have their permissions set up?
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> The permissions you are listing are associated with the symlink, 
>>>> not the underlying device. (And they look unlike any symlink 
>>>> permissions I have ever seen ... on my systems, symlinks always 
>>>> show up as "lrwxrwxrwx" ... perhaps someone can clarify that part?)
>>>>
>>>> Anyway ... check the permissions on the /dev/dsp0 and /dev/mixer0 . 
>>>> They need to be mode 660 (you need write permission in order to use 
>>>> /dev/dsp0 for output) with group audio and the mythtv userid part 
>>>> of group audio. (Obvious other variants are possible, such as mode 
>>>> 666, but that's the setup I usually use.)
>>>>
>>>
>>>
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>>>
>>
>>
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>
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