# What these message means (from dmesg)(SOLVED)?

## pstar

I am trying to install a USB TV tuner which supposes working in Linux. In my laptop, I have

a Ubuntu 8.04 installed, and I got some sort of success being about to get some channel dumped

to my hard drive. But nothing in my Gentoo desktop so far. Right now when I plugin that USB device

after system reboot, it will light up, but all the applications I tried didn't seem find it. and if I unplug it 

and re-plug it again, nothing will happened and no info from dmesg at all.  Here is the dmesg

info when I first plug it in:

 *Quote:*   

> 
> 
> [  160.806074] usb 1-2: adding 1-2:1.0 (config #1, interface 0)
> 
> [  160.806087] usb 1-2:1.0: uevent
> ...

 

From that information, I guess the tuner is not successfully connected, and it has some

trace back information printed out. But that is about all I can get.

 *Quote:*   

> [  161.595175] Pid: 5149, comm: modprobe Tainted: P          (2.6.27-gentoo-r8 #
> 
> 6)

 

So is that means something wrong happened when it trying to load a kernel module, or a system 

call to that?Last edited by pstar on Fri Jan 30, 2009 8:49 am; edited 1 time in total

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## ewaller

I know nothing of your specific device, but things went very badly wrong at:

 *Quote:*   

> [ 161.595132] BUG: unable to handle kernel NULL pointer dereference at 0000000a 

 

By the time you got down to the tainted message it really is telling you that you should consider rebooting because a bad thing happened in the kernel.   

I do not know if you are a programmer, but dereferencing a null pointer means "Use the contents of this variable as a memory address, then go to that address and tell me what is there.  The problem is the variable contains 0 (null).  Looking at the contents of memory address 0 is considered very bad form.

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## ewaller

Okay, I little more looking around at the DVB module and I realize that seems to be a video capture driver which is consistent with the purpose of your device.

You might want to poke around /usr/src/linux/drivers/media/dvb.

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## pstar

I know some C, that is why thinking those dmesg could be useful to someone more knowledgeable.

But I am not sure what you meant by looking at /usr/src/linux/drivers/media/dvb, what am I suppose to do? 

I think it could be some component is missing from my Kernel Vs Kernel from Ubuntu, but I already check

sever times and think I already enabled almost all the possible components in dvb, usb, v4l in my kernel

except drivers I don't think I have, but again I must admit that I know very little about kernels and

never feel confident about all those options and new feature coming through each new kernels.

BTW: The USB tuner I am working with is a Pinnacle PCTV nano 73e and

[url]http://www.smovs.dk/linux/index.php?note=17&subject=Pinnacle%20DVB-T%20nano%20stick%20(PCTV%2073e)[/url]

is what I am following, the only difference is I am using a Gentoo custom kernel instead a pre-compiled Ubuntu one.Last edited by pstar on Tue Jan 27, 2009 11:05 am; edited 1 time in total

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## pstar

Sorry about the link, it just wouldn't come with correct format not matter what I tried. 

Well, it's just too late for me to actually think.

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## eduardhc

 *pstar wrote:*   

> I know some C, that is why thinking those dmesg could be useful to someone more knowledgeable.
> 
> But I am not sure what you meant by looking at /usr/src/linux/drivers/media/dvb, what am I suppose to do? 
> 
> I think it could be some component is missing from my Kernel Vs Kernel from Ubuntu, but I already check
> ...

 

Hi, 

    Check www.linuxtv.org for the state of the support for this card, and specially from what kernel version is supported and how good. The support for the devices based on this chip (Dibcomm 0700) has gone under some changes, recently, and I'm not sure if that specific card s well supported.

Anyway, you can always try to directly use the most recent version of the driver development tree from there, instead of the in-kernel modules. There are some instructions on the LinuxTV DVB wiki for that, and even a Portage ebuild that does all the job for you (I can't remenber the name right now).

regards,

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## pstar

Thank you, it is indeed a DiBcom 7000PC chip, at least after I compile that module in

kernel, it is partially working now. I get two channels in good quality. Strange thing is 

I can not view other channels even I got the channel list, and w_scan also can only get 

those two channels.

Another strange thing is it ask for dvb-usb-dib0700-1.10.fw firmware now, but before I compile

the correct module in kernel, it is asking for dvb-usb-dib0700-1.20 and that not working, I guess 

that is what you means by undergo some changes.

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## eduardhc

 *pstar wrote:*   

> Thank you, it is indeed a DiBcom 7000PC chip, at least after I compile that module in
> 
> kernel, it is partially working now. I get two channels in good quality. Strange thing is 
> 
> I can not view other channels even I got the channel list, and w_scan also can only get 
> ...

 

The 'dvb-usb-dib0700-1.20.fw' is the lastest version of the firmware available for these devices, and it's the one that the current version of the driver (the one currently living in LinuxTV repository) is using, and is also the one used by the driver merged into 2.6.27 (the kernel you are using). 

Have you tried to directly compile an up-to-date version of the drivers in LinuxTV mercurial repository?

Regards, 

  Eduard

PS: anyway, for questions like that you'll probably be luckier to directly post the questions into LinuxTV mail list, as this is the best place to llok for support regarding newest DVB devices like that.

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## pstar

Thank you Eduard again for your information, I did install v4l-dvb-hg before, and that is

where I get the Opps Bug message from, my guess is somthing broken in between the 

new kernel I compiled and the dib700 driver from v4l-dvb or the firmware 1.20 it requires.

If I compile that driver from kernel, at least that TV tuner sort of working but requirs firmware 1.10.

I planed doing some further investigation today, but found lots of things broken. VLC couldn't found

any DVB devices , but Kaffeine could, Xine sort of working at first but stop working after a while,

Mplayer working fine first but stop working after a while, and lsusb just hung. I don't think I can spent

more time for that right now. I will stick with my laptop for TV watching using Windows now, it has all

sorts of problems as well, such as software license fee, codec license fee, performance issue, but the 

bottom line is I know that the driver works.

Hopefully I can contribute something back to LinuxTV, the status now from my experience is miserable,

or maybe kernel 2.6.28 could have some improvement in drivers?

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## eduardhc

 *pstar wrote:*   

> Thank you Eduard again for your information, I did install v4l-dvb-hg before, and that is
> 
> where I get the Opps Bug message from, my guess is somthing broken in between the 
> 
> new kernel I compiled and the dib700 driver from v4l-dvb or the firmware 1.20 it requires.
> ...

 

I don't know about 2.6.28, but LinuxTV holds the lastest version of the drivers, so if these fail probably those merged into 2.6.28 also will.

Anyway, just for trying... I'd recommend that you recompile your kernel WITHOUT the DVB support (uncheck everything under Device Drivers -> Multimedia), and then compile & install the HG drivers. This way we would be sure that you are using the full set of HG drivers and not mixing drivers from in-kernel and HG, which could be causing the kernel oops.

Regards, 

  Eduard

PS: other than that, try to post your problems in LinuxTV DVB list, it's the best place to look for support for DVB devices.

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## pstar

It works   :Very Happy: . Just remove related module from Kernel, and once my PC restarted, it works and with firmware 1.20.

The signal still not good enough for a extended TV lead cable plus two USB extension cables(That is what takes

to reach my PC) except two channels, while I do have all the channels in Windows. But the driver from v4l-dvb now 

working ok and no more Oops from kernel. I guess I could buy a longer RG6 cable which seems working much better, 

if I figure out I do need one.

Thank you Eduard again, without your help I certainly wouldn't got it working by now.   :Razz: 

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## eduardhc

 *pstar wrote:*   

> It works  . Just remove related module from Kernel, and once my PC restarted, it works and with firmware 1.20.
> 
> The signal still not good enough for a extended TV lead cable plus two USB extension cables(That is what takes
> 
> to reach my PC) except two channels, while I do have all the channels in Windows. But the driver from v4l-dvb now 
> ...

 

You're welcome. I suggested you to remove the drivers from the kernel before here, at work, we had a similar problem and we only discovered it afters days of debugging. In theory, when you compile the LinutxTV drivers they overwrite the ones in kernel, but any of them has i.e. changed its name then you end up with a very nasty mix of modules attempting to load at the same time, which usually ends up with a nice "Oops" like that (at least, this is what hapened to us...)

Regards.

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