DMA on /dev/hda but not on /dev/dvd
 

I am trying to enable DMA mode on my dvd-rom to get enough speed to actually play a dvd. My drive supports DMA, so does the controller/motherboard, but I can get it to work. My HD is already running in DMA mode (set at startup), so I can't understand why the dvd doesn't work.

# hdparm -d1 /dev/dvd <-- As root, of course

/dev/dvd:
setting using_dma to 1 (on)
HDIO_SET_DMA failed: Operation not permitted
using_dma = 0 (off)


# hdparm -i /dev/dvd

/dev/dvd:

Model=HITACHI DVD-ROM GD-7500, FwRev=0005, SerialNo=
Config={ Fixed Removeable DTR<=5Mbs DTR>10Mbs nonMagnetic }
RawCHS=0/0/0, TrkSize=0, SectSize=0, ECCbytes=0
BuffType=unknown, BuffSize=0kB, MaxMultSect=0
(maybe): CurCHS=0/0/0, CurSects=0, LBA=yes, LBAsects=0
IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: sdma0 sdma1 sdma2 mdma0 mdma1 *mdma2
UDMA modes: udma0 udma1 udma2
AdvancedPM=no

# hdparm -i /dev/hda

/dev/hda:

Model=MAXTOR 4K040H2, FwRev=A08.1500, SerialNo=572121417537
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
RawCHS=16383/16/63, TrkSize=32256, SectSize=21298, ECCbytes=4
BuffType=DualPortCache, BuffSize=2000kB, MaxMultSect=16, MultSect=16
CurCHS=4047/16/255, CurSects=16511760, LBA=yes, LBAsects=78198750
IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 udma2
AdvancedPM=no WriteCache=enabled
Drive conforms to: ATA/ATAPI-5 T13 1321D revision 1: 1 2 3 4 5


The motherboard is SiS, I don't know the exact details (dmesg says omething about SIS5513, SIS730 ATA 100 controller)

Thanks for any help

Jeremy

First off, try finding where /dev/dvd is pointing to:
ls -l /dev/dvd
Then, taking the actual device, try there:
hdparm -d1 /dev/hdX

If your device is using scsi emulation, determine which standard ide block device it was before emulation occured:
hda = Primary Master
hdb = Secondary Master
hdc = Primary Slave
hdd = Secondary Slave

Also, check the man page, it mentions using the -X option with -d option to ensure it uses the correct dma.

So
hdparm -d1 -X udma2 /dev/hdX
might be what you are looking for.

Cool

Using hdparm -X option didn't help, still same result:

(/dev/dvd is linked to /dev/hdb, btw)

# hdparm -d1 -X udma2 /dev/hdb

/dev/hdb:
setting using_dma to 1 (on)
HDIO_SET_DMA failed: Operation not permitted
setting xfermode to 66 (UltraDMA mode2)
using_dma = 0 (off)

Same result for any of the other DMA modes (sdma0, mdma2)


Thanks for the suggestion, though...

Do a search of the forums, I just noticed you are using RedHat and I recall there is a specific problem with enabling DMA on cdrom/dvdroms with RedHat, there's a setting you have to enter somewhere (I don't remember).

Thanks for the suggestion. I had no idea this problem was specific to rh-8.0. Here's what I found:

---------------------------------------------------------------------
I had the same problem. Here's the solution from Red Hat's web site:

NOTE: As with the 8.0 release, IDE DMA on CD-ROM drives is disabled by
default. If you are sure that your CD-ROM drive is capable of IDE
DMA, place the following line in the /etc/modules.conf file:

options ide-cd dma=1

I did it and now DVD is smooth as silk.
-----------------------------------------------------------------------

I did the same thing, works perfectly