[MPlayer-users] Solution: DVD sluggish (not hdparm)

[Patrick.Debois]

Hi,

just FYI. The documentation mentions the use of hdparm to set the DMA off.

Under Redhat 8.0 it is not that simple: part of the solution is found 
on http://freshrpms.net/docs/dvd/

The error tells you that hdparm fails to set the dma flag:

# hdparm -d1 /dev/hda
> 
> /dev/hda:
>  setting using_dma to 1 (on)
>  HDIO_SET_DMA failed: Operation not permitted
>  using_dma    =  0 (off)


After enabling the "option ide-cd dma=1" you will be able to set it.
You still need to set it with hdparm. (dma=1 is a bit misleading).

Hoping this is usefull, and i think it's something for the documentation.

<extract>
Red Hat Linux does not enable DMA by default on IDE 
CD-ROM and DVD-ROM devices any more since 7.3. This means that you will 
get a choppy playback by default, but it can be easily corrected :

Make the change current using "hdparm -d 1 /dev/dvd" (If you are using 
IDE-SCSI emulation and /dev/dvd points to the SCSI device, you will need 
to use the original /dev/hdX instead).

Make the change permanent by adding a line containing "options ide-cd 
dma=1" to your /etc/modules.conf file (Red Hat Linux 8.0 and higher).

Make the change permanent by copying /etc/sysconfig/harddisks as 
/etc/sysconfig/harddiskhdX (where X is the letter corresponding to your 
device) and uncomment the "USE_DMA=1" line (Red Hat Linux 7.3 and 
earlier).