[ltp] Controlling dvd-drive speed

[Tino Keitel]

On Thu, Apr 10, 2003 at 21:19:27 +0300, Marius Gedminas wrote:
> On Thu, Apr 10, 2003 at 07:52:51PM +0200, Tino Keitel wrote:
> > > I use ide-scsi too, and setcd works just fine.
> > > 
> > >   setcd -x 20 /dev/cdrom
> > > 
> > > where /dev/cdrom is a symlink to /dev/scd0.
> > 
> > What type of drive do you have?
> 
> MATSHITA DVD-ROM SR-8175
> 
> cdrecord -prcap dev=0,0,0 reports maximum read speed of 4224 kB/s.  I
> can set the speed to any number from 1 to 255 with setcd, but the drive
> only supports four distinct speeds: 1056, 2112, 3520, and 4224 kB/s
> (that approximately translates to 7x, 14x, 23x and 28x).  cdrecord
> -prcap shows the currently selected speed.
> 
> > I had no luck on my A30 with 2 Toshiba
> > drives (SD-C2512 DVD-ROM and SD-R2412 DVD/CDRW).
> 
> Any error messages?  Do you have write permissions on the device?

Running as root, setcd reported that the speed was set to the desired
value.

> root < @thinkpad:/home/scorpion$ setcd -x 1 /dev/cdroms/cdrom1 ; cdrecord -prcap | grep "read  speed"
/dev/cdroms/cdrom1:
  Speed set at 150 KB/s (1x)
scsidev: '0,1,0'
scsibus: 0 target: 1 lun: 0
Linux sg driver version: 3.1.24
  Maximum read  speed in kB/s: 4234
  Current read  speed in kB/s: 1058

I tried with a CDROM now and it worked with both drives.

What I noticed is that DVD play speed is not affected by setcd.
However, the SD-R 2412 is very silent while playing a DVD, whereas the
SD-C2512 makes a lot of noise, making it very hard to enjoy watching a
movie. When I tried to read to read a DVD (not playing it) using

dd if=/dev/cdroms/cdrom1 of=/dev/null bs=1024

it runs with full speed, regardless of the setcd -x setting.

Regards,
Tino