Mailing List Archive

On Mon, 21 Jun 2021 23:49:20 +1000, you 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?

Have you by any chance installed some SDR (software defined radio)
packages? It looks like some SDR software is using the tuner.
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On 22/06/2021 02.11, Stephen Worthington wrote:
> On Mon, 21 Jun 2021 23:49:20 +1000, you 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?
>
> Have you by any chance installed some SDR (software defined radio)
> packages? It looks like some SDR software is using the tuner.

The package rtl-sdr was installed just then, as a dependency for rng-tools.
I do not recall installing rng-tools but it was installed years ago. Nothing depends on it.
No related programs are running,

I suspect that some install script was involved during the recent update, probably the newly installed rtl-sdr.

--
Eyal Lebedinsky (eyal@eyal.emu.id.au)
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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@eyal.emu.id.au)
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On Mon, 28 Jun 2021 10:50:23 +1000, you wrote:

>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.

This is a conflict between the rtl-sdr package and the MythTV
packages. If you are not using the SDR software, you should just
remove the SDR packages. If you do want to use the SDR software, you
will need to work out some arrangement that gives MythTV access to the
tuners. Adding the frontend user and backend user ("mythtv") to the
"rtlsdr" group is an option that should work. Another option is to do
chmod a+rw on all the tuner devices. However, MythTV does need
exclusive access to the tuners when it is using them. So if the SDR
software is using them when MythTV wants to, MythTV will fail to
access the tuners. And in MythTV you have to set the option on each
tuner that makes MythTV release access to it when it is not using it.
And you need to turn off EIT use of the tuners, otherwise MythTV will
use them for EIT EPG grabbing when it is not using them for recording.
It would be much easier just to remove the SDR packages.
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On 28/06/2021 14.16, Stephen Worthington wrote:
> On Mon, 28 Jun 2021 10:50:23 +1000, you wrote:
>
>> 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.
>
> This is a conflict between the rtl-sdr package and the MythTV
> packages. If you are not using the SDR software, you should just
> remove the SDR packages. If you do want to use the SDR software, you
> will need to work out some arrangement that gives MythTV access to the
> tuners. Adding the frontend user and backend user ("mythtv") to the
> "rtlsdr" group is an option that should work.

This is my plan B.

> Another option is to do
> chmod a+rw on all the tuner devices.

Done that, and added the chmod command to rc.local too.

> However, MythTV does need
> exclusive access to the tuners when it is using them. So if the SDR
> software is using them when MythTV wants to, MythTV will fail to
> access the tuners. And in MythTV you have to set the option on each
> tuner that makes MythTV release access to it when it is not using it.

Sure. I plan to dedicate one tuner (there are 5) to rtl-sdr if I use it.

> And you need to turn off EIT use of the tuners, otherwise MythTV will
> use them for EIT EPG grabbing when it is not using them for recording.

EIT is already set to run on only one tuner.

> It would be much easier just to remove the SDR packages.

True, and should be trivial to install (with due care) when needed.

However, the general solution should be something that fedora users are unlikely to trip over.
Right now installing rtl-sdr will make mythbackend fail which may not be trivial to diagnose
(took me a while to realize what happened).

cheers

--
Eyal Lebedinsky (eyal@eyal.emu.id.au)
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On 28/06/2021 06:27, Eyal Lebedinsky wrote:
>
>
> On 28/06/2021 14.16, Stephen Worthington wrote:
>> On Mon, 28 Jun 2021 10:50:23 +1000, you wrote:
>>
>>> 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.
>>
>> This is a conflict between the rtl-sdr package and the MythTV
>> packages.  If you are not using the SDR software, you should just
>> remove the SDR packages.  If you do want to use the SDR software, you
>> will need to work out some arrangement that gives MythTV access to the
>> tuners.  Adding the frontend user and backend user ("mythtv") to the
>> "rtlsdr" group is an option that should work.
>
> This is my plan B.
>
>> Another option is to do
>> chmod a+rw on all the tuner devices.
>
> Done that, and added the chmod command to rc.local too.
>
>> However, MythTV does need
>> exclusive access to the tuners when it is using them.  So if the SDR
>> software is using them when MythTV wants to, MythTV will fail to
>> access the tuners.  And in MythTV you have to set the option on each
>> tuner that makes MythTV release access to it when it is not using it.
>
> Sure. I plan to dedicate one tuner (there are 5) to rtl-sdr if I use it.
>
>> And you need to turn off EIT use of the tuners, otherwise MythTV will
>> use them for EIT EPG grabbing when it is not using them for recording.
>
> EIT is already set to run on only one tuner.
>
>> It would be much easier just to remove the SDR packages.
>
> True, and should be trivial to install (with due care) when needed.
>
> However, the general solution should be something that fedora users are
> unlikely to trip over.
> Right now installing rtl-sdr will make mythbackend fail which may not be
> trivial to diagnose
> (took me a while to realize what happened).
>
> cheers
>
I see this is also on the Fedora lists.

I'm running mythtv master with dvb tuners in Fedora 33. No similar
problem seen. rtl-sdr is installed, but I don't have its target device.
Perhaps you do?

rtl-sdr is 'SDR utilities for Realtek RTL2832 based DVB-T dongles' which
can 'turn your ... dongle into an SDR receiver'

John P


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