[pvrusb2] Non-root access to control pvrusb2 driver

[Mike Isely]

On Fri, 5 Jan 2007, G Mc.Pherson wrote:

> Hi Folks,
> 
> I was tooling around with sysfsutils and noticed that it's possible to 
> change the ownership of entries in the /sys subdirectory. By adding the
> following sample entries into /etc/sysfs.conf:
> 
> owner class/pvrusb2/sn-8206665/ctl_freq_table_channel/cur_val=user:user
> owner class/pvrusb2/sn-8206665/ctl_freq_table_value/cur_val=user:user
> owner class/pvrusb2/sn-8206665/ctl_channel/cur_val=user:user
> owner class/pvrusb2/sn-8206665/ctl_frequency/cur_val=user:user
> owner class/pvrusb2/sn-8206665/ctl_input/cur_val=user:user
> owner class/pvrusb2/sn-8206665/ctl_mute/cur_val=user:user
> owner class/pvrusb2/sn-8206665/ctl_volume/cur_val=user:user
> 
> * Note: Change user:user to your user name
> 

Ha!  Great find!  About a year ago there was a discussion going on here 
about being able to change those attributes.  At the time I tried to do 
something at the driver level and quickly realized it was impossible.  
I commented then that the problem could be solved in userland with a 
daemon that would handle setting these attributes appropriately - and 
here we are.  This thing has probably been sitting under our noses the 
entire time :-)

> It's possible control the volume, channel and input controls without 
> having to switch to root. So, as a non-root user, it's possible to:
> 
> echo false > /sys/class/pvrusb2/sn-8206665/ctl_mute/cur_val
> echo 58980 > /sys/class/pvrusb2/sn-8206665/ctl_volume/cur_val
> echo composite > /sys/class/pvrusb2/sn-8206665/ctl_input/cur_val
> 
> I realize most people are using MythTV to interact with their devices, 
> but I thought this information might be useful to those of us who have 
> hacked together our own little scripts to watch/record TV shows.
> 
> For a complete list of these controls, use the following command:
> 
> find /sys/class/pvrusb2/*/* | grep cur_val

This should also work:

ls -d /sys/class/pvrusb2/*/ctl_*

This might be useful to dump out all the controls at once:

> 
> Regards,
> Gord

Thanks.

  -Mike


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