Mailing List Archive: MythTV: Users

Permission problem on /dev/video 0-3

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dardack at gmail

Jul 28, 2010, 7:34 PM

Post #1 of 22 (1455 views)
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Permission problem on /dev/video 0-3

Ok so my fathers mythtv box running .23, 2 days ago was running fine.
Tonite he calls me and says mythtv isn't recording. I go up, information
says recorders has an error. I look in the mythtvbackend log, i see:

Channel(/dev/video0)::Open(): Can't open video device, error "Permission
denied"
Channel(/dev/video1)::Open(): Can't open video device, error "Permission
denied"
Channel(/dev/video2)::Open(): Can't open video device, error "Permission
denied"
Channel(/dev/video3)::Open(): Can't open video device, error "Permission
denied"

I did some searching and say and error with pvr150's and a udev fixing it.
However, both of his are pvr500's. I did try that fix but it didn't work.
The weird thing is, once X is loaded, if I ssh in and run:

sudo service mythtv-backend restart

Everything works fine.

He hasn't done updates (he doesn't without me) in those 2 days.

The permisions on /dev/video0-3 is
crw-rw----- root video

where video has mythtv/hisusername as part of the group.

The udev rules made it:
crw-rw-rw- root video

But again non of this fixes mythbackend running correctly on bootup. I have
to VNC/SSH in and restart the backend, but once I do it works fine.

So if anyone could shed some light on this for me that would be great. I do
have autobuilds for mythbuntu enabled, I believe he's running 25368. Please
help me out here.
--
Sincerely,

MacNean C. Tyrrell

carsten at welcomes-you

Jul 28, 2010, 10:36 PM

Post #2 of 22 (1426 views)
Permalink

Re: Permission problem on /dev/video 0-3 [In reply to]

Hi

On Thursday 29 July 2010 04:34:35 MacNean Tyrrell wrote:

>
> He hasn't done updates (he doesn't without me) in those 2 days.
>
> The permisions on /dev/video0-3 is
> crw-rw----- root video
>
> where video has mythtv/hisusername as part of the group.
>
> The udev rules made it:
> crw-rw-rw- root video
>

That's very weird. Can you double check that user mythtv is running with is
indeed in the video group, i.e. running 'id mythtv'?

Both settings should be fine then.

The only thing left might be that the devices are not created at first, but
somehow only upon restarting the service, but that would be really odd.

Can you check the system logs (especially dmesg) for something odd during
boot-up?

Cheers

Carsten
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bhaskins at chartermi

Jul 29, 2010, 6:21 AM

Post #3 of 22 (1420 views)
Permalink

Re: Permission problem on /dev/video 0-3 [In reply to]

MacNean Tyrrell wrote:
> Ok so my fathers mythtv box running .23, 2 days ago was running fine.
> Tonite he calls me and says mythtv isn't recording. I go up,
> information says recorders has an error. I look in the mythtvbackend
> log, i see:
>
> Channel(/dev/video0)::Open(): Can't open video device, error
> "Permission denied"
> Channel(/dev/video1)::Open(): Can't open video device, error
> "Permission denied"
> Channel(/dev/video2)::Open(): Can't open video device, error
> "Permission denied"
> Channel(/dev/video3)::Open(): Can't open video device, error
> "Permission denied"
>
> I did some searching and say and error with pvr150's and a udev fixing
> it. However, both of his are pvr500's. I did try that fix but it
> didn't work. The weird thing is, once X is loaded, if I ssh in and run:
>
> sudo service mythtv-backend restart
>
> Everything works fine.
>
> He hasn't done updates (he doesn't without me) in those 2 days.
>
> The permisions on /dev/video0-3 is
> crw-rw----- root video
>
> where video has mythtv/hisusername as part of the group.
>
> The udev rules made it:
> crw-rw-rw- root video
>
> But again non of this fixes mythbackend running correctly on bootup.
> I have to VNC/SSH in and restart the backend, but once I do it works
> fine.
>
> So if anyone could shed some light on this for me that would be great.
> I do have autobuilds for mythbuntu enabled, I believe he's running
> 25368. Please help me out here.
> --
> Sincerely,
>
> MacNean C. Tyrrell
> ------------------------------------------------------------------------
> I think that we are seeing the same problem showing up in different ways.
>
I had this hit on several different ways, and it did come from one of
the ub10.4 updates.
The first sign was that mythweb shows blank pages, after that other
problems will
sneak out under the baseboards.
It appears to be a sequencing problem, the backend starts before it should.
The workaround is to restart the backend.
On one box I just gave up and went back to 9.10 ( works fine again ) but
this also had
ongoing problems with hibernation crash and major wireless problems.
Ub10.4 has just not worked well for me, I hope that they can fix it in
10.10.

Does anyone see any advantages to upstart?
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>

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greg12866 at nycap

Jul 29, 2010, 6:55 AM

Post #4 of 22 (1420 views)
Permalink

Re: Permission problem on /dev/video 0-3 [In reply to]

On 07/29/2010 09:21 AM, bhaskins wrote:
> MacNean Tyrrell wrote:
>> Ok so my fathers mythtv box running .23, 2 days ago was running
>> fine. Tonite he calls me and says mythtv isn't recording. I go up,
>> information says recorders has an error. I look in the mythtvbackend
>> log, i see:
>>
>> Channel(/dev/video0)::Open(): Can't open video device, error
>> "Permission denied"
>> Channel(/dev/video1)::Open(): Can't open video device, error
>> "Permission denied"
>> Channel(/dev/video2)::Open(): Can't open video device, error
>> "Permission denied"
>> Channel(/dev/video3)::Open(): Can't open video device, error
>> "Permission denied"
>>
>> I did some searching and say and error with pvr150's and a udev
>> fixing it. However, both of his are pvr500's. I did try that fix
>> but it didn't work. The weird thing is, once X is loaded, if I ssh
>> in and run:
>>
>> sudo service mythtv-backend restart
>>
>> Everything works fine.
>> He hasn't done updates (he doesn't without me) in those 2 days.
>>
>> The permisions on /dev/video0-3 is
>> crw-rw----- root video
>>
>> where video has mythtv/hisusername as part of the group.
>>
>> The udev rules made it:
>> crw-rw-rw- root video
>>
>> But again non of this fixes mythbackend running correctly on bootup.
>> I have to VNC/SSH in and restart the backend, but once I do it works
>> fine.
>>
>> So if anyone could shed some light on this for me that would be
>> great. I do have autobuilds for mythbuntu enabled, I believe he's
>> running 25368. Please help me out here.
>> --
>> Sincerely,
>>
>> MacNean C. Tyrrell
>> ------------------------------------------------------------------------
>> I think that we are seeing the same problem showing up in different
>> ways.
> I had this hit on several different ways, and it did come from one of
> the ub10.4 updates.
> The first sign was that mythweb shows blank pages, after that other
> problems will
> sneak out under the baseboards.
> It appears to be a sequencing problem, the backend starts before it
> should.
> The workaround is to restart the backend.
> On one box I just gave up and went back to 9.10 ( works fine again )
> but this also had
> ongoing problems with hibernation crash and major wireless problems.
> Ub10.4 has just not worked well for me, I hope that they can fix it in
> 10.10.
>
> Does anyone see any advantages to upstart?
>> _______________________________________________
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>
I don't see any advantage,but it seems Ubuntu and all the major distro's
must change things just for the sake of changing things...
I don't use upstart for starting my backend, I put mythbackend in
startup applications..It works for me ..It might not be the most elegant
solution,but who can argue with success... One other pet peeve of mine
is pulse-audio..Why not make that an option for those people who don't
want or need it???
It seems to me they are trying to gain users by making Linux look and
act like Windows...

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mythtv.t.wuuza at xoxy

Jul 29, 2010, 8:44 AM

Post #5 of 22 (1407 views)
Permalink

Re: Permission problem on /dev/video 0-3 [In reply to]

> The udev rules made it:
> crw-rw-rw- root video
>
> But again non of this fixes mythbackend running correctly on bootup. I
have
> to VNC/SSH in and restart the backend, but once I do it works fine.

I started having a similar problem a couple of days ago after getting
kernel and myth updates among others, using Mythbuntu 10.04 with
autobuilds. I have not noticed the problem on boot but rather on resuming
from suspend. I already had a pm-suspend script that runs on resume to
make sure myth works, so I added some logging to see what was going on
with /dev/video*. Apparently something changed in the timing because
/dev/video1 (I force start at 1) for my PVR150 is owned root:root at
first, and only after a few seconds (anywhere from 2-6) does udev change
the ownership to root:video with rw for the group. I have ivtv in the
list of modules for pm-suspend to unload/reload, which is presumably why
/dev/video* needs to be set up on resume, but I'm not sure what other
parts changed that affected the timing. In my resume script I am forced
to bounce the backend anyway because of firewire capture, so my fix was to
loop until the video group appears on /dev/video1 before restarting the
backend, enabling the backend sees the input with the correct permissions.

John

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dardack at gmail

Jul 29, 2010, 8:55 AM

Post #6 of 22 (1413 views)
Permalink

Re: Permission problem on /dev/video 0-3 [In reply to]

On Thu, Jul 29, 2010 at 11:44 AM, <mythtv.t.wuuza [at] xoxy> wrote:

> > The udev rules made it:
> > crw-rw-rw- root video
> >
> > But again non of this fixes mythbackend running correctly on bootup. I
> have
> > to VNC/SSH in and restart the backend, but once I do it works fine.
>
> I started having a similar problem a couple of days ago after getting
> kernel and myth updates among others, using Mythbuntu 10.04 with
> autobuilds. I have not noticed the problem on boot but rather on resuming
> from suspend. I already had a pm-suspend script that runs on resume to
> make sure myth works, so I added some logging to see what was going on
> with /dev/video*. Apparently something changed in the timing because
> /dev/video1 (I force start at 1) for my PVR150 is owned root:root at
> first, and only after a few seconds (anywhere from 2-6) does udev change
> the ownership to root:video with rw for the group. I have ivtv in the
> list of modules for pm-suspend to unload/reload, which is presumably why
> /dev/video* needs to be set up on resume, but I'm not sure what other
> parts changed that affected the timing. In my resume script I am forced
> to bounce the backend anyway because of firewire capture, so my fix was to
> loop until the video group appears on /dev/video1 before restarting the
> backend, enabling the backend sees the input with the correct permissions.
>
> Is there a way to do this in rc.local, i have a loop on my laptop to wait
until iwconfig has an ip address and then mount -a, because samba was not
mounting my shares correctly because the wireless took so long to get an ip
address. So would love a way to wait for mythbackend to start, or restart
mythbackend once mythfrontend is running.

>
> John
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>

--
Sincerely,

MacNean C. Tyrrell

mythtv.t.wuuza at xoxy

Jul 29, 2010, 11:01 AM

Post #7 of 22 (1408 views)
Permalink

Re: Permission problem on /dev/video 0-3 [In reply to]

> Is there a way to do this in rc.local, i have a loop on my laptop to
wait
> until iwconfig has an ip address and then mount -a, because samba was
not
> mounting my shares correctly because the wireless took so long to get an
ip
> address. So would love a way to wait for mythbackend to start, or
restart
> mythbackend once mythfrontend is running.

I don't know. I'm not all that familiar with this stuff, especially since
things have been changing recently (like upstart). If he's got a default
Mythbuntu install then mythtv-backend is an upstart job. You could write
another upstart job that does the checking loop, and then modify the
mythtv-backend job to depend on that one (ie add it to "start on" stanza).
Writing the upstart job is easy - I have one in there that calls the same
firewire primer script as my sleep/resume script does. In Kubuntu 8.04
there was an issue where the backend started before networking was fully
loaded and it never found my HDHomeRun. For that I just took the easy
route and put a "sleep 10" in the backend init script, so that would be
another easy option.

John

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nick.rout at gmail

Jul 29, 2010, 4:44 PM

Post #8 of 22 (1408 views)
Permalink

Re: Permission problem on /dev/video 0-3 [In reply to]

On Fri, Jul 30, 2010 at 6:01 AM, <mythtv.t.wuuza [at] xoxy> wrote:
>> Is there a way to do this in rc.local, i have a loop on my laptop to
> wait
>> until iwconfig has an ip address and then mount -a, because samba was
> not
>> mounting my shares correctly because the wireless took so long to get an
> ip
>> address. So would love a way to wait for mythbackend to start, or
> restart
>> mythbackend once mythfrontend is running.
>
> I don't know. �I'm not all that familiar with this stuff, especially since
> things have been changing recently (like upstart). �If he's got a default
> Mythbuntu install then mythtv-backend is an upstart job. �You could write
> another upstart job that does the checking loop, and then modify the
> mythtv-backend job to depend on that one (ie add it to "start on" stanza).
> �Writing the upstart job is easy - I have one in there that calls the same
> firewire primer script as my sleep/resume script does. �In Kubuntu 8.04
> there was an issue where the backend started before networking was fully
> loaded and it never found my HDHomeRun. �For that I just took the easy
> route and put a "sleep 10" in the backend init script, so that would be
> another easy option.

I suspect the backend is starting before the pvr module is loaded, and
the permission denied message is because the device nodes simply are
not there.

Add a delay to the backend startup script, or restart the backend in
/etc/rc.local.

Supposedly upstart should be able to create a situation where it says
"start the backend after the following modules have loaded" - but the
mythbuntu engineers do not seem to be able to get it to work like
that. (of course everyone has different "modules" that need to load
first)
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dardack at gmail

Jul 29, 2010, 5:49 PM

Post #9 of 22 (1401 views)
Permalink

Re: Permission problem on /dev/video 0-3 [In reply to]

On Thu, Jul 29, 2010 at 7:44 PM, Nick Rout <nick.rout [at] gmail> wrote:

> On Fri, Jul 30, 2010 at 6:01 AM, <mythtv.t.wuuza [at] xoxy> wrote:
> >> Is there a way to do this in rc.local, i have a loop on my laptop to
> > wait
> >> until iwconfig has an ip address and then mount -a, because samba was
> > not
> >> mounting my shares correctly because the wireless took so long to get an
> > ip
> >> address. So would love a way to wait for mythbackend to start, or
> > restart
> >> mythbackend once mythfrontend is running.
> >
> > I don't know. I'm not all that familiar with this stuff, especially
> since
> > things have been changing recently (like upstart). If he's got a default
> > Mythbuntu install then mythtv-backend is an upstart job. You could write
> > another upstart job that does the checking loop, and then modify the
> > mythtv-backend job to depend on that one (ie add it to "start on"
> stanza).
> > Writing the upstart job is easy - I have one in there that calls the
> same
> > firewire primer script as my sleep/resume script does. In Kubuntu 8.04
> > there was an issue where the backend started before networking was fully
> > loaded and it never found my HDHomeRun. For that I just took the easy
> > route and put a "sleep 10" in the backend init script, so that would be
> > another easy option.
>
> I suspect the backend is starting before the pvr module is loaded, and
> the permission denied message is because the device nodes simply are
> not there.
>
> Add a delay to the backend startup script, or restart the backend in
> /etc/rc.local.
>
> That's the thing i did. I have:

/usr/bin/service mythtv-backend restart

But it still doesn't fix it. However, once X is loaded if i run same
command it's fine.

> Supposedly upstart should be able to create a situation where it says
> "start the backend after the following modules have loaded" - but the
> mythbuntu engineers do not seem to be able to get it to work like
> that. (of course everyone has different "modules" that need to load
> first)
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>

--
Sincerely,

MacNean C. Tyrrell

mythtv.t.wuuza at xoxy

Jul 30, 2010, 7:34 AM

Post #10 of 22 (1369 views)
Permalink

Re: Permission problem on /dev/video 0-3 [In reply to]

> I suspect the backend is starting before the pvr module is loaded, and
> the permission denied message is because the device nodes simply are
> not there.

I don't think so, at least in my case. I had stuck some "ls -l" logging
in my scripts. When it gets to my script I get something like:
rw------- root root /dev/video1

After waiting a while, I get
rw-rw---- root video /dev/video1

If ivtv isn't loaded there is no /dev/video1. It seems more like the
module is loading but then the udev rules aren't being applied for a
while. I'm not sure what's causing the delay but it can be 6 seconds or
more in my case.

John

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mythtv.t.wuuza at xoxy

Jul 30, 2010, 9:07 AM

Post #11 of 22 (1355 views)
Permalink

Re: Permission problem on /dev/video 0-3 [In reply to]

> /usr/bin/service mythtv-backend restart

> But it still doesn't fix it. However, once X is loaded if i run same
> command it's fine.

Here's the script I use to delay until the udev permissions are set on my
tuner (ie group is video instead of root). I post this because A) it
might help you and B) if anyone has a better way of doing this I'm
listening. I'm a programmer but not a bash expert. It seems like this
should be possible without a temp file but I couldn't get it to work and
it was getting late the night I was messing with it. I'm sure there are
other ways to check permissions, too.

#!/bin/sh
while true; do
find /dev/video1 -group video > /tmp/waitForVideo
if [ `grep video1 /tmp/waitForVideo` ]; then
break
fi
sleep 1
done

John

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dardack at gmail

Jul 30, 2010, 7:27 PM

Post #12 of 22 (1345 views)
Permalink

Re: Permission problem on /dev/video 0-3 [In reply to]

On Fri, Jul 30, 2010 at 12:07 PM, <mythtv.t.wuuza [at] xoxy> wrote:

> > /usr/bin/service mythtv-backend restart
>
> > But it still doesn't fix it. However, once X is loaded if i run same
> > command it's fine.
>
> Here's the script I use to delay until the udev permissions are set on my
> tuner (ie group is video instead of root). I post this because A) it
> might help you and B) if anyone has a better way of doing this I'm
> listening. I'm a programmer but not a bash expert. It seems like this
> should be possible without a temp file but I couldn't get it to work and
> it was getting late the night I was messing with it. I'm sure there are
> other ways to check permissions, too.
>
> #!/bin/sh
> while true; do
> find /dev/video1 -group video > /tmp/waitForVideo
> if [ `grep video1 /tmp/waitForVideo` ]; then
> break
> fi
> sleep 1
> done
>
>
You stick the command for the script in your rc.local?

Just real quick (i left my program days 12 years ago for accounting/computer
forensics, so bare with me) I know the find command, what does the -group
video do? I mean I get that it's putting whatever the find command finds
into /tmp/wfv and then if there is an entry for video1 breaking, just don't
understand the -group video option.

John
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>

--
Sincerely,

MacNean C. Tyrrell

dardack at gmail

Jul 30, 2010, 7:27 PM

Post #13 of 22 (1343 views)
Permalink

Re: Permission problem on /dev/video 0-3 [In reply to]

On Fri, Jul 30, 2010 at 10:27 PM, MacNean Tyrrell <dardack [at] gmail> wrote:

>
>
> On Fri, Jul 30, 2010 at 12:07 PM, <mythtv.t.wuuza [at] xoxy> wrote:
>
>> > /usr/bin/service mythtv-backend restart
>>
>> > But it still doesn't fix it. However, once X is loaded if i run same
>> > command it's fine.
>>
>> Here's the script I use to delay until the udev permissions are set on my
>> tuner (ie group is video instead of root). I post this because A) it
>> might help you and B) if anyone has a better way of doing this I'm
>> listening. I'm a programmer but not a bash expert. It seems like this
>> should be possible without a temp file but I couldn't get it to work and
>> it was getting late the night I was messing with it. I'm sure there are
>> other ways to check permissions, too.
>>
>> #!/bin/sh
>> while true; do
>> find /dev/video1 -group video > /tmp/waitForVideo
>> if [ `grep video1 /tmp/waitForVideo` ]; then
>> break
>> fi
>> sleep 1
>> done
>>
>>
> You stick the command for the script in your rc.local?
>
> Just real quick (i left my program days 12 years ago for
> accounting/computer forensics, so bare with me) I know the find command,
> what does the -group video do? I mean I get that it's putting whatever the
> find command finds into /tmp/wfv and then if there is an entry for video1
> breaking, just don't understand the -group video option.
>
>
Forgot to add, thank for posting this, next time i'm up at my parents I'll
try it out to see if it fixes his problem.

> John
>>
>> _______________________________________________
>> mythtv-users mailing list
>> mythtv-users [at] mythtv
>> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>>
>
>
>
> --
> Sincerely,
>
> MacNean C. Tyrrell
>

--
Sincerely,

MacNean C. Tyrrell

knowledgejunkie at gmail

Jul 30, 2010, 7:46 PM

Post #14 of 22 (1344 views)
Permalink

Re: Permission problem on /dev/video 0-3 [In reply to]

On 31 July 2010 03:27, MacNean Tyrrell <dardack [at] gmail> wrote:
>
> On Fri, Jul 30, 2010 at 12:07 PM, <mythtv.t.wuuza [at] xoxy> wrote:
>>
>> #!/bin/sh
>> while true; do
>> � � � �find /dev/video1 -group video > /tmp/waitForVideo
>> � � � �if [ `grep video1 /tmp/waitForVideo` ]; then
>> � � � � � � � �break
>> � � � �fi
>> � � � �sleep 1
>> done
>>
>
> You stick the command for the script in your rc.local?
> Just real quick (i left my program days 12 years ago for accounting/computer
> forensics, so bare with me) I know the find command, what does the -group
> video do?

It restricts find's matching to files owned by group "video" - which
is how the script checks that the udev rule has run successfully.

$ man find

gives the details.

Cheers,
Nick

--
Nick Morrott

MythTV Official wiki: http://mythtv.org/wiki/
MythTV users list archive: http://www.gossamer-threads.com/lists/mythtv/users

"An investment in knowledge always pays the best interest." - Benjamin Franklin
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dardack at gmail

Aug 1, 2010, 3:43 PM

Post #15 of 22 (1303 views)
Permalink

Re: Permission problem on /dev/video 0-3 [In reply to]

On Fri, Jul 30, 2010 at 10:46 PM, Nick Morrott <knowledgejunkie [at] gmail>wrote:

> On 31 July 2010 03:27, MacNean Tyrrell <dardack [at] gmail> wrote:
> >
> > On Fri, Jul 30, 2010 at 12:07 PM, <mythtv.t.wuuza [at] xoxy> wrote:
> >>
> >> #!/bin/sh
> >> while true; do
> >> find /dev/video1 -group video > /tmp/waitForVideo
> >> if [ `grep video1 /tmp/waitForVideo` ]; then
> >> break
> >> fi
> >> sleep 1
> >> done
> >>
> >
> > You stick the command for the script in your rc.local?
> > Just real quick (i left my program days 12 years ago for
> accounting/computer
> > forensics, so bare with me) I know the find command, what does the -group
> > video do?
>
> It restricts find's matching to files owned by group "video" - which
> is how the script checks that the udev rule has run successfully.
>
> $ man find
>
> gives the details.
>
> Cheers,
> Nick
>
> --
> Nick Morrott
>
> MythTV Official wiki: http://mythtv.org/wiki/
> MythTV users list archive:
> http://www.gossamer-threads.com/lists/mythtv/users
>
> "An investment in knowledge always pays the best interest." - Benjamin
> Franklin
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
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>

--
Sincerely,

MacNean C. Tyrrell

dardack at gmail

Aug 1, 2010, 3:44 PM

Post #16 of 22 (1298 views)
Permalink

Re: Permission problem on /dev/video 0-3 [In reply to]

On Thu, Jul 29, 2010 at 8:49 PM, MacNean Tyrrell <dardack [at] gmail> wrote:

>
>
> On Thu, Jul 29, 2010 at 7:44 PM, Nick Rout <nick.rout [at] gmail> wrote:
>
>> On Fri, Jul 30, 2010 at 6:01 AM, <mythtv.t.wuuza [at] xoxy> wrote:
>> >> Is there a way to do this in rc.local, i have a loop on my laptop to
>> > wait
>> >> until iwconfig has an ip address and then mount -a, because samba was
>> > not
>> >> mounting my shares correctly because the wireless took so long to get
>> an
>> > ip
>> >> address. So would love a way to wait for mythbackend to start, or
>> > restart
>> >> mythbackend once mythfrontend is running.
>> >
>> > I don't know. I'm not all that familiar with this stuff, especially
>> since
>> > things have been changing recently (like upstart). If he's got a
>> default
>> > Mythbuntu install then mythtv-backend is an upstart job. You could
>> write
>> > another upstart job that does the checking loop, and then modify the
>> > mythtv-backend job to depend on that one (ie add it to "start on"
>> stanza).
>> > Writing the upstart job is easy - I have one in there that calls the
>> same
>> > firewire primer script as my sleep/resume script does. In Kubuntu 8.04
>> > there was an issue where the backend started before networking was fully
>> > loaded and it never found my HDHomeRun. For that I just took the easy
>> > route and put a "sleep 10" in the backend init script, so that would be
>> > another easy option.
>>
>> I suspect the backend is starting before the pvr module is loaded, and
>> the permission denied message is because the device nodes simply are
>> not there.
>>
>> Add a delay to the backend startup script, or restart the backend in
>> /etc/rc.local.
>>
>> That's the thing i did. I have:
>
> /usr/bin/service mythtv-backend restart
>
> But it still doesn't fix it. However, once X is loaded if i run same
> command it's fine.
>

Just was at my dad's. A sleep 25 before restart fixed the problem, probably
could reduce it a bit to 20, but 10 was too soon, i jumped to 25, once
frontend loaded 1 second later it said couldn't find backend, then that
message went away, and the tuners were available.

Supposedly upstart should be able to create a situation where it says
>> "start the backend after the following modules have loaded" - but the
>> mythbuntu engineers do not seem to be able to get it to work like
>> that. (of course everyone has different "modules" that need to load
>> first)
>> _______________________________________________
>> mythtv-users mailing list
>> mythtv-users [at] mythtv
>> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>>
>
>
>
> --
> Sincerely,
>
> MacNean C. Tyrrell
>

--
Sincerely,

MacNean C. Tyrrell

mythtv.t.wuuza at xoxy

Aug 2, 2010, 6:42 AM

Post #17 of 22 (1277 views)
Permalink

Re: Permission problem on /dev/video 0-3 [In reply to]

> You stick the command for the script in your rc.local?

I have mine called in /etc/pm/sleep.d/00-fixMyth, which is called when the
system comes out of suspend. I don't seem to have the problem on boot.

> Just was at my dad's. A sleep 25 before restart fixed the problem,
probably
> could reduce it a bit to 20, but 10 was too soon, i jumped to 25, once
> frontend loaded 1 second later it said couldn't find backend, then that
> message went away, and the tuners were available.

Glad you got it working. My frontend gets started before the network is
fully up, too, and I always have to clear that message.

> Supposedly upstart should be able to create a situation where it says
> "start the backend after the following modules have loaded" - but the
> mythbuntu engineers do not seem to be able to get it to work like
> that. (of course everyone has different "modules" that need to load
> first)

The backend upstart job does have some dependencies but an update must
have changed something because your dad's and mine both worked before last
week.

John

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dardack at gmail

Aug 5, 2010, 1:23 PM

Post #18 of 22 (1192 views)
Permalink

Re: Permission problem on /dev/video 0-3 [In reply to]

On Mon, Aug 2, 2010 at 9:42 AM, <mythtv.t.wuuza [at] xoxy> wrote:

> > You stick the command for the script in your rc.local?
>
> I have mine called in /etc/pm/sleep.d/00-fixMyth, which is called when the
> system comes out of suspend. I don't seem to have the problem on boot.
>
> > Just was at my dad's. A sleep 25 before restart fixed the problem,
> probably
> > could reduce it a bit to 20, but 10 was too soon, i jumped to 25, once
> > frontend loaded 1 second later it said couldn't find backend, then that
> > message went away, and the tuners were available.
>
> Glad you got it working. My frontend gets started before the network is
> fully up, too, and I always have to clear that message.
>
> > Supposedly upstart should be able to create a situation where it says
> > "start the backend after the following modules have loaded" - but the
> > mythbuntu engineers do not seem to be able to get it to work like
> > that. (of course everyone has different "modules" that need to load
> > first)
>
> The backend upstart job does have some dependencies but an update must
> have changed something because your dad's and mine both worked before last
> week.
>
>
I know. Now i'm concered upgrading my backend/frotnends to 10.04. Guess I
won't for now, but when .24 goes stable I guess I will. is there any idea
what changed caused this? And is anyone working on a fix?

> John
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>

--
Sincerely,

MacNean C. Tyrrell

dardack at gmail

Aug 18, 2010, 8:02 AM

Post #19 of 22 (1094 views)
Permalink

Re: Permission problem on /dev/video 0-3 [In reply to]

On Thu, Aug 5, 2010 at 4:23 PM, MacNean Tyrrell <dardack [at] gmail> wrote:

>
>
> On Mon, Aug 2, 2010 at 9:42 AM, <mythtv.t.wuuza [at] xoxy> wrote:
>
>> > You stick the command for the script in your rc.local?
>>
>> I have mine called in /etc/pm/sleep.d/00-fixMyth, which is called when the
>> system comes out of suspend. I don't seem to have the problem on boot.
>>
>> > Just was at my dad's. A sleep 25 before restart fixed the problem,
>> probably
>> > could reduce it a bit to 20, but 10 was too soon, i jumped to 25, once
>> > frontend loaded 1 second later it said couldn't find backend, then that
>> > message went away, and the tuners were available.
>>
>> Glad you got it working. My frontend gets started before the network is
>> fully up, too, and I always have to clear that message.
>>
>> > Supposedly upstart should be able to create a situation where it says
>> > "start the backend after the following modules have loaded" - but the
>> > mythbuntu engineers do not seem to be able to get it to work like
>> > that. (of course everyone has different "modules" that need to load
>> > first)
>>
>> The backend upstart job does have some dependencies but an update must
>> have changed something because your dad's and mine both worked before last
>> week.
>>
>>
> I know. Now i'm concered upgrading my backend/frotnends to 10.04. Guess I
> won't for now, but when .24 goes stable I guess I will. is there any idea
> what changed caused this? And is anyone working on a fix?
>

John (or anyone else), have you updated to a new auto-build in the past few
days and has it fixed the problem? I haven't upgraded my machines at home
because of this problem, and haven't been to my dad's to experiment either.
I was going to wait for .24 to hit before upgrading my machines to 10.04,
but if the problem has been fixed, I'll do it sooner.

> John
>>
>> _______________________________________________
>> mythtv-users mailing list
>> mythtv-users [at] mythtv
>> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>>
>
>
>
> --
> Sincerely,
>
> MacNean C. Tyrrell
>

--
Sincerely,

MacNean C. Tyrrell

mythtv.t.wuuza at xoxy

Aug 20, 2010, 12:10 PM

Post #20 of 22 (1062 views)
Permalink

Re: Permission problem on /dev/video 0-3 [In reply to]

> John (or anyone else), have you updated to a new auto-build in the past
few
> days and has it fixed the problem? I haven't upgraded my machines at
home
> because of this problem, and haven't been to my dad's to experiment
either.
> I was going to wait for .24 to hit before upgrading my machines to
10.04,
> but if the problem has been fixed, I'll do it sooner.

Nope. I read about the problems with the auto-builds for .23.1 or
whatever the issue was, but things have been working smoothly for me (my
fix and Myth in general) so I haven't messed with it.

John

_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

huffcslists at gmail

Aug 21, 2010, 4:31 PM

Post #21 of 22 (1043 views)
Permalink

Re: Permission problem on /dev/video 0-3 [In reply to]

Just went back through this thread after seeing the latest post. I
have been dealing with a similar problem and thought you might benefit
from the solution I came up with.

I am still working through the travails of upgrading from Mythbuntu
9.04 to Mythbuntu 10.04 -- mostly tailoring to personal taste, like
incorporating TuxOnIce support, etherwake from FEs to wake up BE
without having to run up and down stairs to get everything going, etc.

Seems mythbackend was trying to check for video devices sometimes
before LIRC had them up completely, especially when I was resuming
from TuxOnIce-based hibernation.

My solution was to run a script at boot time that checks for the right
group assignment on the /dev/video* (checking video0 seems to be good
enough) and then throw out a "service mythtv-backend restart" to
kick-start mythbackend again.

I have found the video devices taking several seconds, even more than
a dozen, to finish getting configured.

HTH,

Craig.
_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

dardack at gmail

Aug 21, 2010, 5:42 PM

Post #22 of 22 (1040 views)
Permalink

Re: Permission problem on /dev/video 0-3 [In reply to]

On Sat, Aug 21, 2010 at 7:31 PM, Craig Huff <huffcslists [at] gmail> wrote:

> Just went back through this thread after seeing the latest post. I
> have been dealing with a similar problem and thought you might benefit
> from the solution I came up with.
>
> I am still working through the travails of upgrading from Mythbuntu
> 9.04 to Mythbuntu 10.04 -- mostly tailoring to personal taste, like
> incorporating TuxOnIce support, etherwake from FEs to wake up BE
> without having to run up and down stairs to get everything going, etc.
>
> Seems mythbackend was trying to check for video devices sometimes
> before LIRC had them up completely, especially when I was resuming
> from TuxOnIce-based hibernation.
>
> My solution was to run a script at boot time that checks for the right
> group assignment on the /dev/video* (checking video0 seems to be good
> enough) and then throw out a "service mythtv-backend restart" to
> kick-start mythbackend again.
>

Can you post this script for me?

>
> I have found the video devices taking several seconds, even more than
> a dozen, to finish getting configured.
>
> HTH,
>
> Craig.
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>

--
Sincerely,

MacNean C. Tyrrell

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