#77 vhba-module won't compile - missing directory

[Matthew Ewer]

When I try to build vhba-module, it gives me the following:

erhannis@mnode6:~/Downloads/vhba-module-20130607$ make
make -C /lib/modules/3.2.0-4-amd64/build M=/home/erhannis/Downloads/vhba-module-20130607 modules
make: *** /lib/modules/3.2.0-4-amd64/build: No such file or directory.  Stop.
make: *** [modules] Error 2

If I create that "build" directory, it just complains "No rule to make target `modules'."

I'm using Debian 7.4 (Wheezy), amd64.

[Rok Mandeljc]

Sounds like you're missing linux-headers package.

apt-get install linux-headers-$(uname -r)

[Matthew Ewer]

No, I have them. Running the command specified returns "linux-headers-3.2.0-4-amd64 is already the newest version."

[Rok Mandeljc]

Hmm, odd. On my test installation, the contents of /lib/modules/3.2.0-4-amd64 are as follows:

total 2952
lrwxrwxrwx 1 root root 36 Apr 23 06:01 build -> /usr/src/linux-headers-3.2.0-4-amd64
drwxr-xr-x 10 root root 4096 Oct 19 2013 kernel
-rw-r--r-- 1 root root 724651 Apr 28 20:13 modules.alias
-rw-r--r-- 1 root root 700108 Apr 28 20:13 modules.alias.bin
-rw-r--r-- 1 root root 2880 Apr 23 06:01 modules.builtin
-rw-r--r-- 1 root root 3821 Apr 28 20:13 modules.builtin.bin
-rw-r--r-- 1 root root 329784 Apr 28 20:13 modules.dep
-rw-r--r-- 1 root root 455967 Apr 28 20:13 modules.dep.bin
-rw-r--r-- 1 root root 325 Apr 28 20:13 modules.devname
-rw-r--r-- 1 root root 108907 Apr 23 06:01 modules.order
-rw-r--r-- 1 root root 131 Apr 28 20:13 modules.softdep
-rw-r--r-- 1 root root 296126 Apr 28 20:13 modules.symbols
-rw-r--r-- 1 root root 370370 Apr 28 20:13 modules.symbols.bin
lrwxrwxrwx 1 root root 37 Apr 23 06:01 source -> /usr/src/linux-headers-3.2.0-4-common
drwxr-xr-x 3 root root 4096 Oct 19 2013 updates

So 'build' and 'source' are symlinks to directories located in /usr/src. Can you check if /usr/src/linux-headers-3.2.0-4-amd64 and /usr/src/linux-headers-3.2.0-4-common are present on your system? And if they are, try making the symlinks?

[Matthew Ewer]

Great, that worked, in that make and make install reported success. Thanks! I'm still having trouble, though - it doesn't seem like the module was actually installed, or isn't loaded. modinfo vhba and modprobe vhba both return "FATAL: Module vhba not found." .cdemu-daemon.log contains:

Starting CDEmu daemon with following parameters:

 - num devices: 1
 - ctl device: /dev/vhba_ctl
 - audio driver: default
 - bus type: session

cdemu0: Kernel I/O: failed to open control device /dev/vhba_ctl: No such file or directory!
cdemu: Daemon: failed to start device #0!
cdemu: Daemon: failed to create device!
Daemon initialization and start failed!

Do I start a new ticket for this, or what?

[Rok Mandeljc]

Can you try running 'depmod -a' manually as root after 'make install' finishes?

[Matthew Ewer]

Cool, so that made significant progress - after running depmod -a, I also ran modprobe vhba, after which /dev/vhba_ctl appeared. gcdemu, run as root, now appears to work properly. Thanks!

Now, I'm comparing two isos of the same (commercial dvd) disk: one was created via cp /dev/sr0 file.iso (after having opened the disk with VLC, which I get the idea mounts and unencrypts it or something), while the other was created via Brasero. VLC seems to be able to play both of them equally well, directly. However, the first, loaded via GCDEmu, shows many visual and auditory glitches, and outputs many mpeg2video errors to the terminal (like "[mpeg2video @ 0x2514ce0] ac-tex damaged at 36 21" or "[mpeg2video @ 0x2514ce0] skipped MB in I frame at 17 12"). Any idea why this is? It may be the result of some detail in how isos work, rather than CDEmu specifically - the point of this whole exercise in the first place was to figure out the differences between the two isos, though, so I'd be interested if you have an explanation.

[Rok Mandeljc]

Good to hear it worked.

First things first, though, you should not be running the daemon as root, but should instead set read/write permissions on /dev/vhba_ctl so you can run the daemon as user. (see my comment at https://sourceforge.net/p/cdemu/support-requests/20/#d1fd for details)

As for the video issue, my guess would be that the disc is CSS scrambled. The first method likely produces raw (scrambled) image, while Brasero may descramble it for you (is 'dvdcss' plugin enabled in your Brasero (Edit->Plugins)?)

When selecting the file with gCDEmu, can you toggle "Extra options" at the bottom left corner of file selection dialog, and check "Raw image of CSS-encrypted DVD"?

[Matthew Ewer]

Sorry for the delay. So, now, that resulted in further progress - I can play the mounted disk from VLC, now.
Next problem, though: on this disk, in addition to the normal video files, there's also a PDF. When I try to copy or read from the file, I get "Input/output error". (This occurs whether I mount the image to a folder or via gCDEmu.) Any idea why this is? I notice that the size of the iso is smaller than the reported size of the disk, by about 200 MB. It is likewise smaller than the size of the image recorded by Brasero, which image agrees with the reported size of the disk.
...
Hmm. I actually just tried making another iso the same way as before (insert disk, open vlc and play a little of it, cp /dev/sr0 file_2.iso), and it gave me a different iso than the first time. It's the larger size (same as the disk and the Brasero image), and allows me to copy the pdf off.

Any idea why it was different that time around? I hypothesize weird things with how css works. (I realize this is getting a bit far afield.)