[mythtv-users] Cant load bttv module, ALSA module load problem

[Ray Olszewski]

First thing -- these are not MythTV problems. They are kernel problems. So 
if you need extended help, you probably should get it not here but either 
on a Red Hat users' list or a general Linux-support list (an example is 
linux-newbie at vger.kernel.org, a majordomo-run list I participate on).

That said ... it's worth one pass here at your problem, I think.

The difference between modprobe and insmod is that modprobe checks for 
dependencies among modules and loads any additional modules needed to make 
the requested module run. insmod does not do this step, so with insmod, you 
have to load modules in the right order. That's probably what your friend 
told you that you forgot.

But you say you are using modprobe. In that case, the symptom you see most 
likely means that the module you are trying to load was not compiled for 
the kernel you have running. It's not enough that the kernel have the right 
name; oftentimes (not always, but often enough), the module has to be from 
the same compile as the kernel.

So when you compiled your kernel from source, did you follow all the 
required steps, including "make modules" and "make modules_install"? If 
not, that is your problem with the custom kernel.

If I've guessed wrong about the specific error, the general advice still 
applies. In that case, read /usr/src/linux/README, which has a list of the 
steps you need to follow to compile a kernel, install it, compile its 
modules, and install its modules successfully.

As to the add-on compiles you did for the stock kernel ... these may be 
running into the same problem. I always compile my own kernels, so I don't 
have experience trying to compile (say) alsa for a stock kernel. You may 
have the same mismatch problem. Or you may have missed installing (moving 
to /lib/modules/...) some "helper" modules that supplies the missing 
pieces. Or you may not have run "depmod", the app that constructs the 
dependencies list that modprobe uses. Or you may have missed some other 
detail ... I'm writing this off the top of my head, so I'm probably missing 
some possibilities, but the number I am hitting indicates how involved this 
process is.

As to the bttv problems with the stock kernel ... intermittent loading is a 
real oddity. I suggest that before you hand-load it, you run "lsmod" and 
see what modules are loaded. After it loads successfully, do it again and 
see what else loaded. Although I can deliberately misload bttv here and 
generate an "unresolved symbols" message, I cannot get it to happen with 
that *particular* symbol. The only reference I find to that function in the 
kernel source (2.4.19) is in the sound drivers ... and I can't see why the 
bttv module would be generating that particular call. And the function (in 
./drivers/sound/sound_firmware.c) is headed with a comment discouraging its 
use and warning that it might disappear.

Oh, I'd also suggest you pay closer attention to whether there is any 
pattern in the "sometimes-ness" of bttv loading. Like it always fails the 
first time after a reboot but succeeds the second time (which might be what 
you described below). Or it works if loaded after sound but not before 
(which might also be what you described below).

At 10:18 PM 6/6/2003 -0400, Michael Williams wrote:
>Please help, im at my wits end here. I have been lurking for about a
>week and have read hundreds of messages on here about people trials and
>tribulations in getting Myth up and running. I am running RedHat 9, have
>an ATI Tv Wonder VE and know it is card=64 and tuner=2.  My current
>problem is I had the card working using xawtv at work where I was
>configuring the box.  I initially had trouble loading the bttv module
>with insmod, though I dont remember the error offhand.  A friend of mine
>who is good with linux told me to use modprobe to load it, and lo and
>behold it worked.  I used Xawtv to see that it worked.  When I tried to
>use "Watch TV" in mythfrontend I got the same thing I did before I
>actually installed the tuner card, the system locked up hard, had to
>reset it.  I did some more searching in the list archives and found that
>someone had the same problem and it was suggested that their problem was
>the fact they didnt have ALSA installed, so I got the alsa-driv*,
>alsa-lib* and alsa-util* and followed the instructions on the alsa site
>for my sound board (onboard via-82c686 chipset), all the builds and make
>installs worked great but when it came time to modprobe the modules, it
>would load due to this error message:
>
>/lib/modules/2.4.20-8/kernel/sound/acore/snd.o: unresolved symbol
>schedule_work
>/lib/modules/2.4.20-8/kernel/sound/acore/snd.o: insmod
>/lib/modules/2.4.20-8/kernel/sound/acore/snd.o failed
>/lib/modules/2.4.20-8/kernel/sound/acore/snd.o: insmod snd-via82xx
>failed
>
>By now it was time to come home, so I just shut down the box and brought
>it home.  Once i got it set up I booted it up and went to load bttv with
>"modprobe bttv card=64 tuner=2" now i get this message:
>
>/lib/modules/2.4.20-8/kernel/drivers/media/video/bttv.o: unresolved
>symbol mod_firmware_load_R39e3dd23
>/lib/modules/2.4.20-8/kernel/drivers/media/video/bttv.o: insmod
>/lib/modules/2.4.20-8/kernel/drivers/media/video/bttv.o failed
>/lib/modules/2.4.20-8/kernel/drivers/media/video/bttv.o: insmod bttv
>failed
>
>I just tried again to load bttv, and it loaded just fine. I have no idea
>why sometimes it will load and sometimes it wont.  Plus the ALSA thing
>is killing me.
>
>I have searched the list archives, the internet, the docs.  I have
>downloaded a vanilla 2.4.20 kernel source tree and compiled it and
>successfully gotten it to boot, but my nic doesnt work on it nor do any
>of my modules load, none of them (lsmod shows no modules at all).  Its
>like they dont even exist.  I boot back to this one and lsmod shows a
>bunch of modules loaded.
>
>If anyone here feels they can help me and if you want to initiate a
>one-on-one please feel free to email me, im pulling my hair out here.
>Take pity please. :)