[mythtv-users] Indoor HD antenna question

Ashu Desai ashu.desai at gmail.com
Tue Apr 17 16:08:25 UTC 2018


On Fri, Apr 13, 2018 at 2:16 PM Stephen Worthington <
stephen_agent at jsw.gen.nz> wrote:

> On Fri, 13 Apr 2018 17:17:34 +0000, you wrote:
>
> >Seems that the driver doesn't seem to load - or that's what I am getting
> >when I look in the dmesg.
>
> There is some confusion going on here.  MythTV is saying that
> /dev/dvb/adapter0 is an "Air2PC v2" tuner, which is a USB ATSC tuner.
> But the full dmesg does not show any sign of such a tuner.  Instead,
> it shows messages that would be expected for a Avermedia AverTVHD
> card.  But that card is not documented as being an ATSC tuner.  So I
> have to guess that the Avermedia AverTVHD card that you have is
> actually a variant of the card manufactured for the US market that
> does ATSC instead of DVB-T.  Somehow MythTV seems to be giving the
> card the "Air2PC v2" name instead of the correct name.  I do not know
> where MythTV gets those names, so that is possible, but I would have
> expected that it got the name from the hardware or drivers somehow, so
> it is a worry that it has the wrong name.
>
> The error messages about saa7134_alsa are impossible to pin down as to
> which card they apply to.  But the name saa7134 is a chip that is
> likely used on the AverTVHD card.  The _alsa at the end suggests that
> the driver having problems loading is for the audio side of the card,
> rather than video, but any driver not loading is going to cause
> problems.  It might be an idea to try removing the PVR-150 card and
> booting without it to see if those saa7134_alsa error messages go
> away.  That would indicate that the bad driver was being used for the
> PVR-150, rather than the AverTVHD card.
>
> The only way I know of to fix that driver problem is to get a working
> driver from somewhere.  That can involve finding the source code and
> compiling it.  The kernel comes with a set of V4L (Video for Linux)
> drivers that are conservatively chosen - they are older and well
> tested.  But it looks like the testing has missed your card somehow
> and its driver is not compatible - maybe the testers no longer have
> one of your model of tuner card to test with.  If you are lucky, the
> problem you are having has already been fixed in a later version of
> the V4L drivers and if you install the latest version of them, it will
> work.  This page has how to do that:
>
>
> https://www.linuxtv.org/wiki/index.php/How_to_Obtain,_Build_and_Install_V4L-DVB_Device_Drivers
>
> If, after trying the latest V4L drivers, you want to revert back to
> the V4L drivers that are built into kernel packages, you have to
> reinstall all the kernel packages.  The method of doing that depends
> on what distro you are using.
>
> One other option is to go back to an older kernel that is compatible
> with the drivers you have.
>
> It is possible to scan for channels from the command line.  You do
> that by using the "scan" command.  Use "man scan" to tell you the
> options.  In Ubuntu, there is a file here:
>
> /usr/share/dvb/dvb-legacy/atsc/us-ATSC-center-frequencies-8VSB
>
> that provides the "initial-tuning-data-file" for scan's -c option.  It
> contains all the ATSC frequencies, so many may not be used in your
> area and will fail to tune.  Let scan go through the whole list of
> frequencies, which will take a while.  If it will scan, but does not
> see any channels on any frequency, then there is likely a problem with
> the signal from the aerial.  If it will not scan, then the driver
> problem is likely making the tuner non-functional.
>
> I think you said that you connected the aerial directly to a TV and
> the TV could see your channels.  Is that correct?  If so, make sure
> your TV is able to see the channels before you move the connections
> (without bumping the aerial) to the MythTV box and run "scan".  That
> way you can be sure there is a valid signal for the tuner to use.
>
>
 scan /usr/share/dvb/atsc/us-ATSC-center-frequencies-8VSB >
~/Downloads/channels.conf
scanning /usr/share/dvb/atsc/us-ATSC-center-frequencies-8VSB
using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
main:2263: FATAL: failed to open '/dev/dvb/adapter0/frontend0': 16 Device
or resource busy


Basically I tried doing a scan and it keeps saying device is busy.


> In case your distro does not have the us-ATSC-center-frequencies-8VSB
> file or some equivalent, here is what is in it:
>
> root at mypvr:~# cat
> /usr/share/dvb/dvb-legacy/atsc/us-ATSC-center-frequencies-8VSB
> A 57028615 8VSB
> A 63028615 8VSB
> A 69028615 8VSB
> A 79028615 8VSB
> A 85028615 8VSB
> A 177028615 8VSB
> A 183028615 8VSB
> A 189028615 8VSB
> A 195028615 8VSB
> A 201028615 8VSB
> A 207028615 8VSB
> A 213028615 8VSB
> A 473028615 8VSB
> A 479028615 8VSB
> A 485028615 8VSB
> A 491028615 8VSB
> A 497028615 8VSB
> A 503028615 8VSB
> A 509028615 8VSB
> A 515028615 8VSB
> A 521028615 8VSB
> A 527028615 8VSB
> A 533028615 8VSB
> A 539028615 8VSB
> A 545028615 8VSB
> A 551028615 8VSB
> A 557028615 8VSB
> A 563028615 8VSB
> A 569028615 8VSB
> A 575028615 8VSB
> A 581028615 8VSB
> A 587028615 8VSB
> A 593028615 8VSB
> A 599028615 8VSB
> A 605028615 8VSB
> A 611028615 8VSB
> A 617028615 8VSB
> A 623028615 8VSB
> A 629028615 8VSB
> A 635028615 8VSB
> A 641028615 8VSB
> A 647028615 8VSB
> A 653028615 8VSB
> A 659028615 8VSB
> A 665028615 8VSB
> A 671028615 8VSB
> A 677028615 8VSB
> A 683028615 8VSB
> A 689028615 8VSB
> A 695028615 8VSB
> A 701028615 8VSB
> A 707028615 8VSB
> A 713028615 8VSB
> A 719028615 8VSB
> A 725028615 8VSB
> A 731028615 8VSB
> A 737028615 8VSB
> A 743028615 8VSB
> A 749028615 8VSB
> A 755028615 8VSB
> A 761028615 8VSB
> A 767028615 8VSB
> A 773028615 8VSB
> A 779028615 8VSB
> A 785028615 8VSB
> A 791028615 8VSB
> A 797028615 8VSB
> A 803028615 8VSB
>
>
I get the list as well.
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