DMA ???

DMA ???

Post by kj » Tue, 30 Mar 2004 00:21:57



I have installed xine to view DVDs on my laptop.  It works almost
OK.  The only problem is that frames get lost, so the playback is
not smooth.  I ran the utitlity xine-check, which reported the
following:

[ hint ] Your DVD drive seems not to be attached via ATAPI.
         This might be due to the use of an ide-scsi emulation.
         If you really have a SCSI DVD drive, your SCSI controller is likely
         to do perfect DMA, so there's no reason to worry about this.
         However, if you're using ide-scsi, there is a chance that DMA is
         disabled for the DVD drive. Moreover, I don't know how to enable
         DMA in that case, so you probably have to live with some performance
         loss. (FIXME: check for /proc/ide, provide solution)

I can barely understand what this paragraph says (hardware is not
exactly my strength).  I am 99.99% sure that my DVD drive is not
SCSI.  Is there any way for me to (a) determine whether DMA is
disabled for my DVD drive, and (b) enable it if it is?  Also, what's
the deal with the "check for /proc/ide"?

My machine is a Toshiba laptop (Satellite 1905-S301) with a 15"
XGA TFT active-matrix display (1024 x 768), and an ATI Radeon
Mobility M6 LY video card.  My kernel is 2.4.18.  My distro is
Debian 3.0.  I'm sure I'm missing some crucial info here, but I'd
be happy to post it if you tell me what it is (and maybe how to
determine it).  In particular, I am not sure what driver my DVD is
using (or how to find out).

Many thanks in advance!

kynn
--
NOTE: In my address everything before the period is backwards.

 
 
 

DMA ???

Post by Andreas Jansse » Tue, 30 Mar 2004 01:04:42


Hello


> I have installed xine to view DVDs on my laptop.  It works almost
> OK.  The only problem is that frames get lost, so the playback is
> not smooth.  I ran the utitlity xine-check, which reported the
> following:

> [DMA perhaps not enabled]

> I can barely understand what this paragraph says (hardware is not
> exactly my strength).  I am 99.99% sure that my DVD drive is not
> SCSI.  Is there any way for me to (a) determine whether DMA is
> disabled for my DVD drive, and (b) enable it if it is?  Also, what's
> the deal with the "check for /proc/ide"?

It very probably is an IDE drive. However you can use it with the ide-cd
driver, or with the ide-scsi emulation driver. The latter is necessary
on your system to use IDE CD/DVD writers. Use /sbin/lsmod to find out
which driver you use (after acessing the drive). Either the ide-scsi
module is loaded (in that case you use ide-scsi), or the ide-cd module
is loaded (or none of the two, because some kernels have the ide-cd
driver built-in). However for switching on DMA it doesn't matter
whether you ide-cd or ide-scsi.

Check this link to see how you can enable DMA on your system (the only
parameter you need for hdparm right now is -d1, don't use the other
ones if you are not sure that your hardware supports them):

<http://www.andreasjanssen.de/debian-tipps.html#a38>

best regards
        Andreas Janssen

--

PGP-Key-ID: 0xDC801674
Registered Linux User #267976
http://www.andreas-janssen.de/debian-tipps.html

 
 
 

DMA ???

Post by J Krugma » Tue, 30 Mar 2004 04:21:38



Quote:>Check this link to see how you can enable DMA on your system (the only
>parameter you need for hdparm right now is -d1, don't use the other
>ones if you are not sure that your hardware supports them):
><http://www.andreasjanssen.de/debian-tipps.html#a38>

Thank you for your post.  This link is very helpful (thanks to
Google's translation tool!).  I just have one more stupid question:
how can I determine what designator (hdb? hdc? etc.) to use to
refer to my DVD drive?  My fstab file says:

/dev/hda2       /               ext2    errors=remount-ro       0       1
/dev/hda1       none            swap    sw                      0       0
proc            /proc           proc    defaults                0       0
/dev/fd0        /floppy         auto    user,noauto             0       0
/dev/cdrom      /cdrom          iso9660 ro,user,noauto          0       0
/dev/dvd        /dvd            auto    ro,user,noauto          0       0
/dev/hde1       /flashcard      vfat    user,noauto             0       0

therefore I tried

  sudo hdparm -d1 /dev/dvd

but I got the response

  /dev/dvd not supported by hdparm

Since /dev/dvd is a link to /dev/scd0, I also tried

  sudo hdparm -d1 /dev/scd0

but I got the same error message.

How can I find out the correct designator for my DVD drive?

Thanks!

kynn
--
To  s&e^n]d  me  m~a}i]l  r%e*m?o\v[e  bit from my a|d)d:r{e:s]s.

 
 
 

DMA ???

Post by Tim McCo » Tue, 30 Mar 2004 07:16:32




>>Check this link to see how you can enable DMA on your system (the only
>>parameter you need for hdparm right now is -d1, don't use the other
>>ones if you are not sure that your hardware supports them):

>><http://www.andreasjanssen.de/debian-tipps.html#a38>

> Thank you for your post.  This link is very helpful (thanks to
> Google's translation tool!).  I just have one more stupid question:
> how can I determine what designator (hdb? hdc? etc.) to use to
> refer to my DVD drive?  My fstab file says:

> /dev/hda2       /               ext2    errors=remount-ro       0       1
> /dev/hda1       none            swap    sw                      0       0
> proc            /proc           proc    defaults                0       0
> /dev/fd0        /floppy         auto    user,noauto             0       0
> /dev/cdrom      /cdrom          iso9660 ro,user,noauto          0       0
> /dev/dvd        /dvd            auto    ro,user,noauto          0       0
> /dev/hde1       /flashcard      vfat    user,noauto             0       0

> therefore I tried

>   sudo hdparm -d1 /dev/dvd

> but I got the response

>   /dev/dvd not supported by hdparm

> Since /dev/dvd is a link to /dev/scd0, I also tried

>   sudo hdparm -d1 /dev/scd0

> but I got the same error message.

> How can I find out the correct designator for my DVD drive?

> Thanks!

> kynn

SCSI devices aren't supported by hdparm. The best way to ensure DMA is
active is to enable it on the master device. There's no reason why you
should be passing a DVD drive over to SCSI emulation - but it shouldn't
matter.

I assume you have only one drive in the laptop. Do a "dmesg |grep hd" and
check that your drive is indeed the secondary channel slave (hdc). If not,
just change the command accordingly. Once you know the drive:

# hdparm -d1 /dev/hdc

You may want to put it into a boot script so thigns are turned on nicely
for you. On my Debian systems, if I'm being dodgey, I sometimes just add a
line at the end of "/etc/init.d/bootmisc.sh" - simple replicate the
command in the bootmisc.sh file (right at the very bottom, as a new line)
and it'll happen magically at boot.

On a side note, my laptop is a Celeron 400MHz, with 4MB (Neomagic) video
card. With a 2.6.3 kernel I can play fullscreen (i.e. scaled) DVDs and
DivXs with only about 60 - 70% CPU usage. I've always had issues with Xine
on cutback systems - I would strongly recommend MPlayer as a brilliant
allround media player. In my experiences, it's far more efficient and
smarter than most apps. What I'm suggesting is a kernel rebuild, and then
an source or rpm install of MPlayer, and you probably won't recognise your
machine!

http://www.mplayerhq.hu

Good luck!

Tim

--
http://members.swiftdsl.com.au/~tmccoy

ICQ: 160341067

 
 
 

DMA ???

Post by Andreas Jansse » Tue, 30 Mar 2004 08:39:49


Hello




>>Check this link to see how you can enable DMA on your system (the only
>>parameter you need for hdparm right now is -d1, don't use the other
>>ones if you are not sure that your hardware supports them):

>><http://www.andreasjanssen.de/debian-tipps.html#a38>

> Thank you for your post.  This link is very helpful (thanks to
> Google's translation tool!).

The page is available in english and german.

Quote:> I just have one more stupid question:
> how can I determine what designator (hdb? hdc? etc.) to use to
> refer to my DVD drive?  My fstab file says:
> /dev/cdrom      /cdrom          iso9660 ro,user,noauto          0   0
> /dev/dvd        /dvd            auto    ro,user,noauto          0   0

Try

ls -l /dev/cdrom /dev/dvd

to see where the symlinks point to. If they point to SCSI device files
(/dev/scd* or /dev/sg*), e.g. if you use ide-scsi emulation, you have
to use dmesg:

dmesg | grep CD
dmesg | grep DVD

Or you check the contents of /proc/bus/ide.

best regards
        Andreas Janssen

--

PGP-Key-ID: 0xDC801674
Registered Linux User #267976
http://www.andreas-janssen.de/debian-tipps.html

 
 
 

1. to DMA or not to DMA with SCSI

I'm currently running SLS 1.02 Linux using IDE drives.

I'll be getting a big SCSI hard drive to serve as a spool file
for C-News.

I've read a good review on the Future Domain TMC-1680 SCSI-2 controller.

Does this controller do DMA?

If not, what benefits will I get by buying a DMA SCSI controller?

What DMA SCSI controller you recommend?

Thanks for the info!
--

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