[TriLUG] RH 7.1 DMA + IDE CDROM problem

[al johson]

Why not just buy another CD-ROM drive? They are very cheap right now.
Actually just about all computer parts are very cheap right now. I doubled
my RAM and it cost less than $50 installed! There is another hamfest coming
in Nov. in Benson which will have lots of cheap PC parts, if you can wait.
Will give more details later on.

----- Original Message -----
From: Ken Wahl <kenwahl at ipass.net>
To: Triangle Linux User's Group <trilug at trilug.org>
Sent: Saturday, September 08, 2001 2:36 AM
Subject: [TriLUG] RH 7.1 DMA + IDE CDROM problem


> Howdy,
>
> Having a little trouble turning DMA off permanently for my cdrom drive
> on RH 7.1.  It's an ATAPI 40x CDROM drive and unfortunely one of
> those that cannot be used in DMA mode under RH 7.1 .  RH wants to put it
> into DMA mode by default even though BIOS is set for PIO Mode 4.
> This issue is documented at http://www.exocore.com/linux.rh171dma/
>
> The suggested workaround is to issue a hdparm -d 0 in rc.local
> I've done this but shortly after bootup (or giving command at console),
> somewhere within an hour, the drive is put back in DMA mode.  I don't
> know exactly what causes this but suspect that the device is polled for
> autotuning after rmmod unloads the cdrom driver and subsequently resets
> the device for DMA.
>
> I know I could pass the kernel parameter "ide1=nodma" at boot time but
> the IDE channel is shared with a hard disk that I would like to keep in
> DMA mode if I could.
>
> Could anyone suggest another workaround that would disable DMA for that
> device permenently?  Is "hdd=nodma" a legitimate parameter?  I didn't
> see it listed in the list of passable kernel parameters at LDP.
>
> Here is the output of hdparm -i /dev/hdd
>
> /dev/hdd:
>
>  Model=CRD-8400C, FwRev=1.02, SerialNo=1999/03/29
>  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
>
> and hdparm /dev/hdd
>
>  HDIO_GET_MULTCOUNT failed: Invalid argument
>  HDIO_GET_NOWERR failed: Invalid argument
>  HDIO_GETGEO failed: Invalid argument
>
> /dev/hdd:
>  I/O support  =  0 (default 16-bit)
>  unmaskirq    =  0 (off)
>  using_dma    =  1 (on)
>  keepsettings =  1 (on)
>  readonly     =  1 (on)
>  readahead    =  8 (on)
>
> I set keepsettings to on after turning using_dma to off but as you can
> see it wasn't kept.
>
> dmesg shows:
>
> Uniform CD-ROM driver unloaded
> ide-floppy driver 0.97
> hdd: set_drive_speed_status: status=0x51 { DriveReady SeekComplete Error }
> hdd: set_drive_speed_status: error=0xb4
> hdd: ATAPI 40X CD-ROM drive, 128kB Cache, DMA
> Uniform CD-ROM driver Revision: 3.12
>
> The mobo is a EFA E5TX-AT with Intel Triton 430TX chipset.  (OK, stop
> snickering..)
>
> As always, thanks for any help/suggestions.
> --
> Ken Wahl    ken at kenwahl.org     http://www.kenwahl.org/
> GnuPG Key At: http://www.ipass.net/~kenwahl/kenwahl.gpg
> Linux: Robust, non-proprietary penguin computing power.
> Red Hat Linux Using Kernel 2.4.7-2 Uptime: 10 days, 11:50
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