[mythtv-users] /dev/dvb permissions

[Eyal Lebedinsky]

On 21/06/2021 23.49, Eyal Lebedinsky wrote:
> After a recent update (fedora 34) mythbackend failed to show any card.
> Short story:
>      crw-rw----+ 1 root rtlsdr 212,  3 Jun 20 23:10 /dev/dvb/adapter0/frontend0
> so user mythtv cannot open it. chmod fixed it, and I added this to my startup scripts.
> 
> Was this an intended change? This update brought in
>      mythtv-backend-31.0-17.147.20210421git05c16580e1.fc34.x86_64
> and friends as well as
>      kernel-5.12.11-300.fc34.x86_64
>      rtl-sdr-0.6.0-9.fc34.x86_64
> 
> The group rtlsdr is new:
>      Jun 20 22:43:17 e7 groupadd[1678612]: group added to /etc/group: name=rtlsdr, GID=440
>      Jun 20 22:43:17 e7 groupadd[1678612]: group added to /etc/gshadow: name=rtlsdr
>      Jun 20 22:43:17 e7 groupadd[1678612]: new group: name=rtlsdr, GID=440
> 
> Is there a possible conflict?
> Should user mythtv be added to the new group?

I still do not know what the correct action should be.

1) I see
	/usr/lib/udev/rules.d/10-rtl-sdr.rules
is setting the group rtlsdr to a list of devices which includes my tuners 0bda:2838
Is this proper to do so when there are other users of these devices?

2) If root.rtlsdr is correct, should the user 'mythtv' also be a member of 'rtlsdr'?
    How should this be done without every mythtv user doing it manually once the backend fails?
    Is this an issue to be dealt with by the rtl-sdr folks?

I suspect that the rtl-sdr package caused the new group to be applied to the devices without
consideration for other users of these devices.

I will raise this conflict on the fedora list, however mythtv is from @rpmfusion and rtl-sdr is from @fedora.

-- 
Eyal Lebedinsky (eyal at eyal.emu.id.au)