Antonio Olivares wrote:
--- Jeff Spaleta <jspaleta@xxxxxxxxx> wrote:
On Nov 26, 2007 4:30 PM, Antonio Olivares
<olivares14031@xxxxxxxxx> wrote:
If one enables hdparm DVD playback will not be
jumpy, however when applying hdparm I get
Perhaps the libata faq will give you the most basic
answer
http://linux-ata.org/faq.html#old_ioctls
Now are you sure that the drive isn't already using
dma by default?
hdparm -i /dev/cdrom
will list the supported DMA modes and will indicate
which one is
currently in use. By default my DVD drive has the
most advanced DMA
enabled by default
DMA modes: sdma0 sdma1 sdma2 mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 *udma2
* signifies the current active mode
[root@localhost ~]# hdparm -i /dev/cdrom
/dev/cdrom:
Model=TSSTcorpCD/DVDW SH-S182D ,
FwRev=SB03 , 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:227,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
* signifies the current active mode
[root@localhost ~]#
So it's using DMA already at the highest supported speed. Have you
checked readahead?
blockdev --getra /dev/cdrom
I suggest at least 8MB of readahead here, that should keep up with the
demand. Note: don't go crazy with this, people have reported learning
experiences with settings in the 32MB range. If 8 doesn't do it, that's
not likely to be the problem.
blockdev --setra 8192 /dev/cdrom
It's likely that the reason you are not having success is that your are
solving the wrong problem. Are you running a recent kernel? The 2.6.23
and later CFS scheduler may help.
--
Bill Davidsen <davidsen@xxxxxxx>
"We have more to fear from the bungling of the incompetent than from
the machinations of the wicked." - from Slashdot
