CDROM drive by UUID in fstab

[Haines Brown]

I went over to UUID for my hard disks and some external storage
devices. I also use ubsmount for usb sticks. However, I don't know what
to do about my DVD drive. It does not seem to have a unique ID number:

dmesg | grep DVD
ata1.01: ATAPI: Optiarc DVD RW AD-7240S, 1.02, max UDMA/100
scsi 0:0:1:0: CD-ROM Optiarc DVD RW AD-7240S 1.02 PQ: 0 ANSI: 5

For some reason, my DVD drive seems to be assigned a somewhat random
interface:

$ ls /dev | grep dvd
dvd5
dvdrw5

In any case, mplayer can't play DVDs. It spins up, but after a couple
minutes trying to access the DVD drive, it just stops. I have trouble
understanding this return:

$ mplayer dvd://1 /dev/dvd5
MPlayer SVN-r31918 (C) 2000-2010 MPlayer Team
...
mplayer: could not connect to socket
mplayer: No such file or directory
Failed to open LIRC support. You will not be able to use your remote control.

Playing dvd://1.
libdvdread: Using libdvdcss version 1.2.10 for DVD access
libdvdread: Can't stat /dev/dvd
No such file or directory
libdvdread: Could not open /dev/dvd
Couldn't open DVD device: /dev/dvd (No such file or directory)
No stream found to handle url dvd://1

Playing /dev/dvd5.
Seek failed
libavformat file format detected.
[mp3 @ 0x92d9370] Header missing
Last message repeated 139 times
[mp3 @ 0x92d9370] big_values too big
[mp3 @ 0x92d9370] Header missing
Last message repeated 997 times
[mp3 @ 0x92e7c90] Estimating duration from bitrate, this may be inaccurate
[lavf] stream 0: audio (mp1), -aid 0
==========================================================================
Opening audio decoder: [mp3lib] MPEG layer-2, layer-3
big_values too large!
AUDIO: 8000 Hz, 2 ch, s16le, 8.0 kbit/3.12% (ratio: 1000->32000)
Selected audio codec: [mp3] afm: mp3lib (mp3lib MPEG layer-2, layer-3)
==========================================================================
AO: [alsa] 8000Hz 2ch s16le (2 bytes per sample)
Video: no video
Starting playback...
big_values too large!
...
big_values too large!) of 661022.8 (183:37:02.7) 135.2%
...
Blocktype == 0 and window-switching == 1 not allowed.
[a lot more messages like the last three]
mpg123: Can't rewind stream by 754 bits!3:37:02.7) 201.3%
Blocktype == 0 and window-switching == 1 not allowed.9.0%
A:661022.8 (183:37:02.7) of 661022.8 (183:37:02.7) 144.7%
Audio output truncated at end.
A:661022.8 (183:37:02.7) of 661022.8 (183:37:02.7) 144.7%

Exiting... (End of file)

My question is, can I or should I set up my DVDRW drive with a UUID?
Would the "AD-7240S" serve to distinguish my DVD drive? Would this be
likely to resolve mplayer's probem accessing the disk?

Haines Brown

[Bit Twister]

On Wed, 21 Dec 2011 15:37:58 -0500, Haines Brown wrote:

> libdvdread: Can't stat /dev/dvd
> No such file or directory

> My question is, can I or should I set up my DVDRW drive with a UUID?

I would be impressed if you could.

> Would the "AD-7240S" serve to distinguish my DVD drive?

Depends on where you would make that decision and what you did with it where.

> Would this be likely to resolve mplayer's probem accessing the disk?

Maybe depending on how you implement your changes. You may want to read
http://www.catb.org/~esr/faqs/smart-questions.html


On my Mandriva Linux 2011.0 system, running KDE 4.6.5.

I have a cd/dvd RW (/dev/sr0) and a cd/dvd R only drive (/dev/sr1).
Out of the box install usually sets the read only device as cdrom/dvd/... :(

Not wanting to use /dev/dvd1 or cdrom1 to get to the burner, I used/modified
/etc/udev/rules.d/70-persistent-cd.rules to create the /dev links to
the device I wanted. Result:

$ cd /dev
$ ls -al | grep sr0
lrwxrwxrwx 1 root root 3 Dec 21 15:35 cdrom -> sr0
lrwxrwxrwx 1 root root 3 Dec 21 15:35 cdrw -> sr0
lrwxrwxrwx 1 root root 3 Dec 21 15:35 dvd -> sr0
lrwxrwxrwx 1 root root 3 Dec 21 15:35 dvdrw -> sr0
brw-rw---- 1 root cdrom 11, 0 Dec 21 15:35 sr0

$ ls -al | grep sr1
lrwxrwxrwx 1 root root 3 Dec 21 15:35 cdrom1 -> sr1
lrwxrwxrwx 1 root root 3 Dec 21 15:35 dvd1 -> sr1
brw-rw---- 1 root cdrom 11, 1 Dec 21 15:35 sr1

I also have added my login id to the audio, disk, cdrom groups. :-)

[J G Miller]

On Wednesday, December 21st, 2011, at 15:37:58h -0500, Haines Brown wrote:

> I went over to UUID for my hard disks and some external storage devices.

Actually you did not.

You "went over to UUID" for the disk partitions / file systems on
each of your hard disks.

> However, I don't know what to do about my DVD drive.

Because a "drive" by it-self does not have any partitions / file systems,
does it?

[David W. Hodgins]

On Wed, 21 Dec 2011 15:37:58 -0500, Haines Brown <hai...@historicalmaterialism.info> wrote:

> My question is, can I or should I set up my DVDRW drive with a UUID?

No. You could setup fstab entries using uuid for filesystems stored
on a data disc, but not for the drive itself.

Depending on which distribution and version you have, there is likely
a file similar in name to /etc/udev/rules.d/70-persistent-cd.rules
that controls which device name gets assigned to the drive.

If you replace a drive, or switch which connector a drive is using
a new entry will be added to that file, ensuring the device always
gets the same name.

Try deleting all of the non-comment lines from that file, and
rebooting. It should then create a entry assigning the drive
to /dev/dvd.

Regards, Dave Hodgins


--
Change nomail.afraid.org to ody.ca to reply by email.
(nomail.afraid.org has been set up specifically for
use in usenet. Feel free to use it yourself.)

[Haines Brown]

"David W. Hodgins" <dwho...@nomail.afraid.org> writes:

> On Wed, 21 Dec 2011 15:37:58 -0500, Haines Brown <hai...@historicalmaterialism.info> wrote:
>
>> My question is, can I or should I set up my DVDRW drive with a UUID?
>
> No. You could setup fstab entries using uuid for filesystems stored
> on a data disc, but not for the drive itself.

Understood

> Depending on which distribution and version you have, there is likely
> a file similar in name to /etc/udev/rules.d/70-persistent-cd.rules
> that controls which device name gets assigned to the drive.

There are two stanzas there for my dvd drive, which have the lines,
among others:

SUBSYSTEM=="block", ENV{ID_CDROM}=="?*",
ENV{ID_PATH}=="pci-0000:00:1f.2-scsi-1:0:0:0",
SYMLINK+="dvd", ENV{GENERATED}="1"

SUBSYSTEM=="block", ENV{ID_CDROM}=="?*",
ENV{ID_PATH}=="pci-0000:00:1f.2-scsi-0:0:1:0",
SYMLINK+="dvd5", ENV{GENERATED}="1"

However, thre is no /dev/dvd.

$ ls -la /dev | grep dvd
lrwxrwxrwx 1 root root 3 Dec 22 09:49 dvd5 -> sr0
lrwxrwxrwx 1 root root 3 Dec 22 09:49 dvdrw5 -> sr0

Perhaps removing lines associated with my dvd drive in
700persistent-cd.rules and rebooting will reconstruct a /dev/dvd, but if
if that file already has a dvd line, why isn't there a /dev/dvd?

But meanwhile, to play a dvd I assume I have to do:

$ mplayer dvd://1 /dev/dvd5

The gui window merely flashes and this is from the trace of the calls:

execve("/usr/bin/mplayer", ["mplayer", "dvd://1", "/dev/dvd5"], [/* 27 vars */]) = 0
brk(0) = 0x9580000
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
...
ioctl(0, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig -icanon -echo ...}) = 0
write(1, "\nPlaying /dev/dvd5.\n", 20) = 20
open("/dev/dvd5.ifo", O_RDONLY|O_LARGEFILE) = -1 ENOENT (No such file or directory)
open("/dev/dvd5.idx", O_RDONLY|O_LARGEFILE) = -1 ENOENT (No such file or directory)
open("/home/haines/.mplayer/sub/dvd5.ifo", O_RDONLY|O_LARGEFILE) = -1 ENOENT (No such file or directory)
open("/home/haines/.mplayer/sub/dvd5.idx", O_RDONLY|O_LARGEFILE) = -1 ENOENT (No such file or directory)
open("/dev/dvd5", O_RDONLY|O_LARGEFILE) = 3
_llseek(3, 0, [4565041152], SEEK_END) = 0
...
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 2048) = 2048
read(3, 0x95c73d8, 2048) = -1 EIO (Input/output error)
read(3, 0x95c73d8, 2048) = -1 EIO (Input/output error)
munmap(0xb4baf000, 2101248) = 0
write(1, "libavformat file format detected"..., 34) = 34
_llseek(3, 0, [0], SEEK_SET) = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 2048) = 2048
...
read(4, "\1\1\200\0\0\0\0\0\2\0\0\2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", 4096) = 32
read(4, 0x95effd0, 4096) = -1 EAGAIN (Resource temporarily unavailable)
close(4) = 0
munmap(0xb404f000, 633604) = 0
munmap(0xb40ea000, 790528) = 0
munmap(0xb41ab000, 633604) = 0
munmap(0xb4246000, 790528) = 0
write(1, "\nExiting... (End of file)\n", 26) = 26
munmap(0xb4d6f000, 266240) = 0
exit_group(0) = ?

I don't know what to make of all this, but it seems that mplayer is
accessing the dvd disk in the drive and extracts some information, but
for some reason can't display it.

Haines Brown

[J G Miller]

On Thursday, December 22nd, 2011 at 10:54:48h -0500,
Haines Brown explained:

> I don't know what to make of all this, but it seems that mplayer is
> accessing the dvd disk in the drive and extracts some information, but
> for some reason can't display it.

If it is an encrypted DVD (most commercial ones are), do you have
the DeCSS library installed?

Package: libdvdcss2
Priority: optional
Section: libs
Installed-Size: 88
Maintainer: Christian Marillat <mari...@debian.org>
Bugs: mailto:mari...@debian.org
Architecture: i386
Source: libdvdcss
Version: 1.2.11-0.0

Description: Simple foundation for reading DVDs - runtime libraries
To allow applications to access some of the more advanced features
of the DVD format.

Homepage: http://download.videolan.org/

You need to get it from the debian-multimedia repository.

[Haines Brown]

J G Miller <mil...@yoyo.ORG> writes:

> On Thursday, December 22nd, 2011 at 10:54:48h -0500,
> Haines Brown explained:
>
>> I don't know what to make of all this, but it seems that mplayer is
>> accessing the dvd disk in the drive and extracts some information, but
>> for some reason can't display it.
>
> If it is an encrypted DVD (most commercial ones are), do you have
> the DeCSS library installed?

Yes, it is an encrypted DVD, but I have libdvdcss2 installed. The
disk is one that I've played before on this same machine.

Haines Brown

[Bill Marcum]

Notice the difference between the two entries. Perhaps your present dvd
drive does not fit this rule:

> ENV{ID_PATH}=="pci-0000:00:1f.2-scsi-1:0:0:0",

--
"Never believe the attribution of a quotation you find on the Internet."
(George Bernard Shaw)

[Haines Brown]

Bill Marcum <bi...@lat.localnet> writes:

> On 2011-12-22, Haines Brown <hai...@HistoricalMaterialism.info> wrote:
>> "David W. Hodgins" <dwho...@nomail.afraid.org> writes:

>> There are two stanzas there for my dvd drive, which have the lines,
>> among others:
>>
>> SUBSYSTEM=="block", ENV{ID_CDROM}=="?*",
>> ENV{ID_PATH}=="pci-0000:00:1f.2-scsi-1:0:0:0",
>> SYMLINK+="dvd", ENV{GENERATED}="1"
>>
>> SUBSYSTEM=="block", ENV{ID_CDROM}=="?*",
>> ENV{ID_PATH}=="pci-0000:00:1f.2-scsi-0:0:1:0",
>> SYMLINK+="dvd5", ENV{GENERATED}="1"
>>
>> However, thre is no /dev/dvd.

> Notice the difference between the two entries. Perhaps your present dvd
> drive does not fit this rule:
>> ENV{ID_PATH}=="pci-0000:00:1f.2-scsi-1:0:0:0",

I see the difference but am too ignorant to know what to make of
it. What is the "path" to? What do the end numbers refer to? My DVD
drive is standard, good quality, and is not very old, so I'd assume
that it would meet system expectations. It seems there is a rule for
"dvd" but no corresponding interface /dev/dvd.

But I now realize that the trace info above simply reports the
70persistent-cd.rules. Could I edit those rules so that "dvd" stana
acquires the value 0:0:1:0? Or would I do better and do what you
suggested, which is to remove the lines and reboot so that they are
regenerated?

I've been complete absorbed by intense work in last two months, and one
effect is that a key combination close to one or two I use all the time
(not sure, but may be C-A-Q) crashes my machine. Could have happened
five times to yield the dvd5. I'll test it, and if that is the offending
key combination I'll have to block it so that I don't do it again.

Haines Brown

[Bit Twister]

On Fri, 23 Dec 2011 06:15:11 -0500, Haines Brown wrote:
> I see the difference but am too ignorant to know what to make of
> it. What is the "path" to? What do the end numbers refer to?

One is the hardware bus id, the other the scsi channel used by the
system to channel data to the device. What you are interested in is
the last two digits of the scsi id to identify which device you want
associated with what SYMLINK and what the symlink will be.

Here look at my two devices. Memorex is read/writer and ASUS is reader.

# grep CD-ROM /var/log/messages
Dec 23 16:58:47 localhost kernel: scsi 3:0:0:0: CD-ROM Memorex DVD+-RAM
Dec 23 16:58:47 localhost kernel: scsi 3:0:1:0: CD-ROM ASUS DVD-E616A

My udev rules snippet:
ENV{ID_PATH}=="pci-0000:00:14.1-scsi-1:0:0:0", SYMLINK+="dvd",
ENV{ID_PATH}=="pci-0000:00:14.1-scsi-1:0:0:0", SYMLINK+="dvdrw",
ENV{ID_PATH}=="pci-0000:00:14.1-scsi-1:0:1:0", SYMLINK+="dvd1",

No idea why messages has 3:0:x:x and rules has 1:0:x:x

the results are
# cd /dev
# ls -al | grep dvd
lrwxrwxrwx 1 root root 3 Dec 23 11:32 dvd -> sr0
lrwxrwxrwx 1 root root 3 Dec 23 11:32 dvdrw -> sr0
lrwxrwxrwx 1 root root 3 Dec 23 11:32 dvd1 -> sr1

[David W. Hodgins]

On Fri, 23 Dec 2011 06:15:11 -0500, Haines Brown <hai...@historicalmaterialism.info> wrote:

> Bill Marcum <bi...@lat.localnet> writes:
>
>> On 2011-12-22, Haines Brown <hai...@HistoricalMaterialism.info> wrote:
>>> "David W. Hodgins" <dwho...@nomail.afraid.org> writes:
>
>>> There are two stanzas there for my dvd drive, which have the lines,
>>> among others:
>>>
>>> SUBSYSTEM=="block", ENV{ID_CDROM}=="?*",
>>> ENV{ID_PATH}=="pci-0000:00:1f.2-scsi-1:0:0:0",
>>> SYMLINK+="dvd", ENV{GENERATED}="1"
>>>
>>> SUBSYSTEM=="block", ENV{ID_CDROM}=="?*",
>>> ENV{ID_PATH}=="pci-0000:00:1f.2-scsi-0:0:1:0",
>>> SYMLINK+="dvd5", ENV{GENERATED}="1"
>>>
>>> However, thre is no /dev/dvd.
>
>> Notice the difference between the two entries. Perhaps your present dvd
>> drive does not fit this rule:
>>> ENV{ID_PATH}=="pci-0000:00:1f.2-scsi-1:0:0:0",
>
> I see the difference but am too ignorant to know what to make of
> it. What is the "path" to? What do the end numbers refer to? My DVD
> drive is standard, good quality, and is not very old, so I'd assume
> that it would meet system expectations. It seems there is a rule for
> "dvd" but no corresponding interface /dev/dvd.

The above indicates that at one time you either had a dvd drive connected
to a different connector.

You should remove both entries and reboot. When udev restarts, it will
add a new entry with the symlink set to dvd and the correct path for
the currently detected device.