Mailing List Archive: Black screen / no volume problem with recent mercurial source

Black screen / no volume problem with recent mercurial source

drescherjm at gmail

May 8, 2009, 6:22 AM

Post #1 of 6 (3795 views)

Since about 1 month ago I have had a serious problem that is reducing
the WAF (wife acceptance factor) since it seems to manifest only on
the her shows. I mean about 1 day a week I get blank recordings from
my hauppage pvr 500. What I mean is the screen is black with no volume
for the entirety of the recording. Before 1 month ago this had never
happened. There are no error messages in dmesg or mythtv at all. When
the tuner gets into this blank screen mode if I

mplayer /dev/video1

I do get a blank screen with no sound as well.

This seems to be more frequent on a reboot or restarting of mythtv.

Since I updated to the latest myth 0.21 fixes svn, updated to a
2.6.27.21 kernel and to the bleeding edge ivtv all at the same time I
can not rule out any of these so this makes it difficult to debug.

Also when it did this yesterday (seemed to be triggered by restarting
mythbackend) after stoping mythbackend I could not modprobe -r ivtv
because it said that the device was in use. However I do not believe
this was the case. There were no myth processes running and I did not
have any other captures running either.

Has anyone had this problem? Ideas how to debug this?

--
John M. Drescher

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Re: Black screen / no volume problem with recent mercurial source [ In reply to ]

awalls at radix

May 8, 2009, 2:07 PM

Post #2 of 6 (3660 views)

On Fri, 2009-05-08 at 09:22 -0400, John Drescher wrote:
> Since about 1 month ago I have had a serious problem that is reducing
> the WAF (wife acceptance factor)

A critical metric that I must monitor at my home as well. :)

> since it seems to manifest only on
> the her shows. I mean about 1 day a week I get blank recordings from
> my hauppage pvr 500. What I mean is the screen is black with no volume
> for the entirety of the recording. Before 1 month ago this had never
> happened. There are no error messages in dmesg or mythtv at all.

And nothing in /var/log/messages either?

When this happens maybe you could turn on lots of ivtv debugging:

# echo 2047 > /sys/modules/ivtv/parameters/debug

to turn on very verbose debugging. Then try taking some action to start
or stop a capture.
(modinfo ivtv will show you what the debug flags mean: 2047 is a bit
excessive)

Also

$ v4l2-ctl -d /dev/video1 --log-status

mmight show something interesting when you're hung up - I don't know

> When
> the tuner gets into this blank screen mode if I
>
> mplayer /dev/video1
>
> I do get a blank screen with no sound as well.
>
> This seems to be more frequent on a reboot or restarting of mythtv.
>
> Since I updated to the latest myth 0.21 fixes svn, updated to a
> 2.6.27.21 kernel and to the bleeding edge ivtv all at the same time I
> can not rule out any of these so this makes it difficult to debug.
>
> Also when it did this yesterday (seemed to be triggered by restarting
> mythbackend) after stoping mythbackend I could not modprobe -r ivtv
> because it said that the device was in use.

That happens for two reasons that I can think of:

1) the mplayer child process is not dead and still has the device open
(if you used mplayer). Kill the offending mpayer process. You could
also do an fuser on /dev/video* /dev/vbi* /dev/radio* to see what
process has what device node open.

2) The kernel oops'ed or bug'ed in the ivtv driver. When this happens,
you won't be able to unload the module, but dmesg or /var/log/messages
should have something in it.

Regards,
Andy

> However I do not believe
> this was the case. There were no myth processes running and I did not
> have any other captures running either.
>
>
> Has anyone had this problem? Ideas how to debug this?
>

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Re: Black screen / no volume problem with recent mercurial source [ In reply to ]

drescherjm at gmail

May 8, 2009, 2:19 PM

Post #3 of 6 (3664 views)

> That happens for two reasons that I can think of:
>
> 1) the mplayer child process is not dead and still has the device open
> (if you used mplayer). Kill the offending mpayer process. You could
> also do an fuser on /dev/video* /dev/vbi* /dev/radio* to see what
> process has what device node open.
>
> 2) The kernel oops'ed or bug'ed in the ivtv driver. When this happens,
> you won't be able to unload the module, but dmesg or /var/log/messages
> should have something in it.
>

Thanks for all the advice. I will try this over the weekend..

John

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Re: Black screen / no volume problem with recent mercurial source [ In reply to ]

drescherjm at gmail

May 10, 2009, 7:21 PM

Post #4 of 6 (3648 views)

>> What I mean is the screen is black with no volume
>> for the entirety of the recording. Before 1 month ago this had never
>> happened. There are no error messages in dmesg or mythtv at all.
>
> And nothing in /var/log/messages either?
>
I did not find anything suspicious in /var/log/messages.

I did not have time to try to reproduce this over the weekend however
I expect some evening this week I will have time.

John

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Re: Black screen / no volume problem with recent mercurial source [ In reply to ]

awalls at radix

May 10, 2009, 7:52 PM

Post #5 of 6 (3640 views)

On Sun, 2009-05-10 at 22:21 -0400, John Drescher wrote:
> >> What I mean is the screen is black with no volume
> >> for the entirety of the recording. Before 1 month ago this had never
> >> happened. There are no error messages in dmesg or mythtv at all.
> >
> > And nothing in /var/log/messages either?
> >
> I did not find anything suspicious in /var/log/messages.
>
>
> I did not have time to try to reproduce this over the weekend however
> I expect some evening this week I will have time.

Don't rush on my account.

I'll only be able to respond via IRC on freenode #v4l and #linuxtv this
week (no personal email) with sporadic hours at that.

Regards,
Andy

> John
>
> _______________________________________________
> ivtv-users mailing list
> ivtv-users@ivtvdriver.org
> http://ivtvdriver.org/mailman/listinfo/ivtv-users
>

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Re: Black screen / no volume problem with recent mercurial source [ In reply to ]

drescherjm at gmail

Jun 14, 2009, 7:42 PM

Post #6 of 6 (3383 views)

On Sun, May 10, 2009 at 10:52 PM, Andy Walls<awalls@radix.net> wrote:
> On Sun, 2009-05-10 at 22:21 -0400, John Drescher wrote:
>> >> What I mean is the screen is black with no volume
>> >> for the entirety of the recording. Before 1 month ago this had never
>> >> happened. There are no error messages in dmesg or mythtv at all.
>> >
>> > And nothing in /var/log/messages either?
>> >
>> I did not find anything suspicious in /var/log/messages.
>>
>>
>> I did not have time to try to reproduce this over the weekend however
>> I expect some evening this week I will have time.
>
> Don't rush on my account.
>
> I'll only be able to respond via IRC on freenode #v4l and #linuxtv this
> week (no personal email) with sporadic hours at that.
>

BTW, This has not happened again in over a month with over 50 recorded
programs. I know I have just jinxed myself for even thinking that...

John

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