Re: dma on as default

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On 8/28/06, Brian Chadwick <[email protected]> wrote:
>> > Is there some way to  make permanent/default the change operated by
>> > '/sbin/hdparm -d1 /dev/dvd', i.e., choosing dma on as default?
>> >
>> the best setting is very often selected automatically ... what version
>> of fedora are u using?
>>
>> do hdparm -i /dev/hdx ... and have a look at the dma modes ... the
>> current mode is indicated by a *
>>
>> u only need to use hdparm if that highest dma mode is not the current
>> setting
>
> Thanks, Brian. I am using FC5. And
>
> # /sbin/hdparm -i /dev/dvd
>
> /dev/dvd:
>
> Model=_NEC DVD_RW ND-3520A, FwRev=1.04, SerialNo=
> Config={ 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=yes, 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
>
> * signifies the current active mode
>
> #
>
> And now?
>
hmmm......i have never seen hdparm not return a current mode ... intriguing.

anyway ... the permanent way to save the changes is to put a command in
your /etc/rc.d/rc.local file

edit that file and at the end of the file put in "/sbin/hdparm /dev/hdx
-your-parameters"

from the output of hdparm i would try "/sbin/hdparm /dev/hdx -d1 -m32 -X
udma2" where hdx is like hdc or hdd .. whichever device /dev/dvd is
linked to. i suppose using a symbolic link (dvd) to the real drive is ok
... but i like to directly address the device

that is the highest performance the drive will support ... what it means
is ... use dma, and use 32 bit access, and use udma2 dma mode. If the
drive does not perform properly with that setting, progressivley try
less aggressive settings....eg. -X udma1, -X udma0, -X mdma2, ... etc

you are using a recent motherboard chipset, so i doubt you will need to
reduce the settings from what i have suggested .. though i must say i am
perplexed that hdparm has not indicated a current mode ...
Put the line

/sbin/hdparm /dev/hdf -d1 -m32 -X udma2

in /etc/rc.d/rc.local, and then

the line

/sbin/hdparm /dev/hdf -d1

but after a reboot, in both cases, I get

# /sbin/hdparm /dev/dvd

/dev/dvd:
IO_support   =  0 (default 16-bit)
 unmaskirq    =  1 (on)
using_dma    =  0 (off)
 keepsettings =  0 (off)
 readonly     =  0 (off)
 readahead    = 256 (on)
HDIO_GETGEO failed: Inappropriate ioctl for device
#

Paul


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