[mythtv] Too much EIT activity causing defective recordings

John Pilkington johnpilk222 at gmail.com
Thu Aug 2 08:51:15 UTC 2018

On 02/08/18 04:50, Stephen Worthington wrote:
> On Thu, 2 Aug 2018 08:21:00 +1000, you wrote:
>> I have an afatech 399U and it is woeful when both channels are running.
>> USB2 and not a good implementation I think. I had to stop using it for
>> myth or only enable 1 tuner. Good eough for random PC watching though so
>> thats what it was relegated to.
>> Cant say about the 499U.
> Yes, now that you remind me, I also have an Afatech 399UR, and while
> each of its dual tuners works fine individually, the Linux drivers for
> it have never had a fix for the problem where it has to select the
> correct tuner for one bit of hardware that is attached to both tuners.
> The result is that when both tuners are used, that bit of hardware
> gets used by both tuners at once instead of sequentially and the
> recordings fail.  The problem is nothing to do with the USB2
> implementation, it is a simple problem of the drivers not having an
> appropriate locking system for use of shared hardware.
> If the 499U is the same, then it can not be used in Linux with both
> tuners active at the same time.  I have moved my 399UR to my Windows
> box where it works fine.

We're talking about quite old devices here.  I don't recollect problems 
in using the 449U/USB2 with both tuners active, but I have used it 
mainly at lower priority than the PCI device.

$ dmesg | grep adapter
[   19.786458] DVB: registering new adapter (Kworld UB499-2T T09)
[   20.207621] usb 1-2: DVB: registering adapter 1 frontend 0 (Afatech 
AF9033 (DVB-T))...
[   20.726906] DVB: registering new adapter (Kworld UB499-2T T09)
[   20.745025] usb 1-2: DVB: registering adapter 2 frontend 0 (Afatech 
AF9033 (DVB-T))...
[   24.444032] DVB: registering new adapter (saa7133[0])
[   24.444043] saa7134 0000:07:04.0: DVB: registering adapter 0 frontend 
0 (Philips TDA10046H DVB-T).

Usually I have scheduled them in order adapter 0, 2, 1 because of the 
expected defect rate, but maybe this was really a product of the EIT 
configuration then.  With my new usb-unticked-box configuration, and not 
much testing, all seem good.  As usual with tuners, YMMV.

But the UB499 has not been entirely reliable in initialisation at boot 
with some 'recent' kernels.  I'm using

$ uname -r

because historically the standard el7 kernel has not used the adapter_nr 
settings in /etc/modprobe.d/dvb.conf

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