2003-09-06 18:44:51

by Max O'Shea

[permalink] [raw]
Subject: bug/request: multi-processing for CD devices

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Hello,

I don't know if this would be considered a 'bug', maybe more of a feature
request?

Summary: request for multi-processing for CD devices (I think the word is
'multi-processing' - ie. so that you can play an audio CD and browse the
audio CD using a program such as konqueror at the same time)

Full description: At the moment, if you are playing an audio CD with one
program and you start accessing the audio CD with another program, the music
will stop playing.

Keywords: audio, sound, /dev/hdc , /dev/ide0, alsa, oss

Here's a little bit of system information if it helps:

Kernel Version: Linux version 2.4.21-0.13mdkcustom (root@tuxmachine) (gcc
version 3.2.2 (Mandrake Linux 9.1 3.2.2-3mdk)) #1 Sat Jul 5 12:27:17 BST 2003

- --------------------------------------
Processor information: processor
: 0
vendor_id : GenuineIntel
cpu family : 6
model : 6
model name : Celeron (Mendocino)
stepping : 5
cpu MHz : 498.495
cache size : 128 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca
cmov pat pse36 mmx fxsr
bogomips : 992.87

- --------------------------------------
Module information:

ppp_deflate 4536 0 (autoclean)
zlib_inflate 21348 0 (autoclean) [ppp_deflate]
zlib_deflate 21624 0 (autoclean) [ppp_deflate]
bsd_comp 5336 0 (autoclean)
binfmt_misc 7404 1
ide-cd 35776 1 (autoclean)
parport_pc 27208 1 (autoclean)
lp 8480 0 (autoclean)
parport 36960 1 (autoclean) [parport_pc lp]
i810 65440 23
agpgart 43680 7 (autoclean)
es1371 30472 0
soundcore 6628 0 [es1371]
ac97_codec 13576 0 [es1371]
gameport 3412 0 [es1371]
ppp_async 9408 1
ppp_generic 24636 3 [ppp_deflate bsd_comp ppp_async]
slhc 6628 0 [ppp_generic]
af_packet 15528 0 (autoclean)
floppy 57148 0
eepro100 22836 1 (autoclean)
mii 3992 0 (autoclean) [eepro100]
nls_iso8859-15 4092 1 (autoclean)
nls_cp850 4316 1 (autoclean)
vfat 12780 1 (autoclean)
fat 39224 0 (autoclean) [vfat]
supermount 16480 3 (autoclean)
sr_mod 17976 0
cdrom 33920 0 [ide-cd sr_mod]
scsimon 9824 0 (unused)
usb-storage 78648 0
scsi_mod 106548 3 [sr_mod scsimon usb-storage]
usb-uhci 26220 0 (unused)
usbcore 77760 1 [usb-storage usb-uhci]
rtc 8412 0 (autoclean)
ext3 59916 2
jbd 38972 2 [ext3]

- --------------------------------------
Output of /proc/devices :

Character devices:
1 mem
2 pty/m%d
3 pty/s%d
4 tts/%d
5 cua/%d
6 lp
7 vcs
10 misc
14 sound
29 fb
108 ppp
128 ptm
136 pts/%d
162 raw
180 usb
226 drm

Block devices:
1 ramdisk
2 fd
3 ide0
9 md
11 sr
22 ide1

- --------------------------------------

Output of /proc/mounts :

rootfs / rootfs rw 0 0
/dev/root / ext3 rw 0 0
none /dev devfs rw 0 0
none /proc proc rw 0 0
none /proc/bus/usb usbdevfs rw 0 0
none /dev/pts devpts rw 0 0
/dev/hda7 /home ext3 rw 0 0
none /mnt/cdrom supermount ro 0 0
none /mnt/cdrw supermount ro 0 0
none /mnt/floppy supermount rw,sync 0 0
/dev/hda1 /mnt/windows vfat rw 0 0
none /proc/sys/fs/binfmt_misc binfmt_misc rw 0 0


I am not subscribed to the linux-kernel list (well, I was, but after I had to
delete 100000 messages and my email account was ready to be closed, I had to
unsubscribe) so if you could possibly cc: me if you can be bothered to or if
you really need to.

Many thanks :-)

- --Max.
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2003-09-06 18:56:22

by Michael Buesch

[permalink] [raw]
Subject: Re: bug/request: multi-processing for CD devices

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On Saturday 06 September 2003 21:45, Max O'Shea wrote:
> Hello,

Hi,

> Summary: request for multi-processing for CD devices (I think the word is
> 'multi-processing' - ie. so that you can play an audio CD and browse the
> audio CD using a program such as konqueror at the same time)
>
> Full description: At the moment, if you are playing an audio CD with one
> program and you start accessing the audio CD with another program, the
> music will stop playing.

As far as I know that should be impossible, because audio-playing
runs 100% on the cd-rom hardware itself. The OS has nothing to do
with it.
So your request should go to the device manufacturers and ask
them if they could build devices, that are "multithreaded". :)
(But it maybe, that this was total crap and I better had thrown
this mail to /dev/null. I'm not 100% sure. 8-) )

- --
Regards Michael Buesch [ http://www.tuxsoft.de.vu ]
Animals on this machine: some GNUs and Penguin 2.6.0-test4-bk2

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2003-09-06 20:07:05

by Mehmet Ceyran

[permalink] [raw]
Subject: RE: bug/request: multi-processing for CD devices

>> Summary: request for multi-processing for CD devices (I
>> think the word is 'multi-processing' - ie. so that you can
>> play an audio CD and browse the audio CD using a program
>> such as konqueror at the same time)
>> [...]
> As far as I know that should be impossible, because
> audio-playing runs 100% on the cd-rom hardware itself. The OS
> has nothing to do with it. So your request should go to the
> device manufacturers and ask them if they could build
> devices, that are "multithreaded". :)

Well that depends. The classic audio CD access is through hardware. The
drive spins down to 1x speed and dumps the data over its private line to
the soundcard's CDDA input channel. So in this case you're right.

The other way to do it is ripping the data through the drive's data bus,
like DAC tools do, and play the music on the fly. This way
'multi-processing' is possible.

So what you have to do is to find an audio player that plays CDDA with
the second method.

Mehmet