[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

Re: hdparm question: HDIO_SET_DMA failed: Inappropriate ioctl for device



Antonio Olivares wrote:
--- Jeff Spaleta <jspaleta gmail com> wrote:

On Nov 26, 2007 4:30 PM, Antonio Olivares
<olivares14031 yahoo com> 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 tmr com>
  "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]