On Tuesday 04 February 2003 10:15 am, Len Lawrence wrote:
> Apologies for the length of this post. A little while ago somebody
> recommended my setting the DVD/CDROM for DMA operation to eliminate
> jerkiness when viewing DVDs. I got hold of hdparm and tried it out,
> without much apparent success. Does the following mean that DMA is
> already enabled for the drive?
>
> [root@localhost lcl]# /sbin/hdparm -i /dev/hdd
>
> /dev/hdd:
>
> Model=IDE DVD-ROM 16X, FwRev=V3.10, 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 udma0 udma1 *udma2
> AdvancedPM=no
>
>
> [root@localhost lcl]# /sbin/hdparm -X66 -d1 /dev/hdd
>
> /dev/hdd:
> setting using_dma to 1 (on)
> HDIO_SET_DMA failed: Operation not permitted
> setting xfermode to 66 (UltraDMA mode2)
> Segmentation fault
>
>
> [root@localhost lcl]# /sbin/hdparm -X66 -d0 /dev/hdd
>
> /dev/hdd:
> setting using_dma to 0 (off)
> HDIO_SET_DMA failed: Operation not permitted
> setting xfermode to 66 (UltraDMA mode2)
> Segmentation fault
>
> But:
> [root@localhost lcl]# /sbin/hdparm -X12 -d0 /dev/hdd
>
> /dev/hdd:
> setting using_dma to 0 (off)
> HDIO_SET_DMA failed: Operation not permitted
> setting xfermode to 12 (PIO flow control mode4)
> using_dma = 0 (off)
>
> No segfault with the following but no success either.
>
> [root@localhost hdd]# /sbin/hdparm -d1 /dev/hdd
>
> /dev/hdd:
> setting using_dma to 1 (on)
> HDIO_SET_DMA failed: Operation not permitted
> using_dma = 0 (off)
>
> cat /proc/ide/ide1/hdd/settings confirms that DMA is disabled.
>
> This is all very confusing. So how to get rid of the jerkiness? This
> is a 1.8 GHz Athlon XP 2200+ with the nVidia driver for Mandrake 8.2,
> and 512 Mb RAM. The jerkiness was unaffected by installation of the
> new video driver. On the old machine, 500 MHz Pentium III with 256 Mb
> RAM the disk plays perfectly smoothly, but in that case DMA is enabled,
> by default.
>
> Could this be a hardware problem, like a jumper setting? No manual for
> the drive. The invoice describes it as a "16X generic DVD drive".
could be the cable even... are you useing a good (80 pin) ide cable?
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