dma timeout expiry

[Rick Stevens]

On Fri, 2006-08-04 at 16:44 -0700, Paul Campbell wrote:
> I have been trying to get
> an install of fedora 5 or RH AS 4 up 3
> on a Dell Precision 360 with limited sucess.
> 
> I have been able to get thru the install and boot
> process by specifying "nodma" but after the install
> io to the drive seems to very slow. Too slow to use
> for development.

The "nodma" is generally only required for the CD or DVD device, and
then usually during the install only.  Once the live kernel is up and
running, nodma can usually be turned off.  The problem is, whatever was
specified on the command line during the install is propagated to the
grub commands and must be manually removed--the thought being that if
you needed it during install, you'll probably need it during normal
operation.  In the case of "nodma", that's usually NOT the case.

The installer's kernel is known to have issues with DMA and CD/DVDs on
certain hardware platforms.  The effects can be minimized by specifying
the offending device on the command line:

	hdc=nodma

This assumes that /dev/hdc (the master drive on the secondary IDE
controller) is the CD/DVD device and is causing the error.

Following the install, try removing the parameter from the "kernel" line
in the /boot/grub/grub.conf file, reboot and see how the machine
behaves.  Alternately, you can use hdparm to re-enable DMA on your
hard drive(s) while the system is running:

	hdparm -d1 /dev/hda

assuming /dev/hda [master drive on primary IDE interface] is your hard
drive.  Remember the mapping:

	/dev/hda	master drive on primary interface
	/dev/hdb	slave drive on primary interface
	/dev/hdc	master drive on secondary interface
	/dev/hdd	slave drive on secondary interface

> Machine has two WD 1200 JB disks
> 
> These are the Messages that I was getting before
> I specified nodma
> 
> dma timeout expiry status = 0x61
> dma timeout error status = 0x58
> Drive Ready
> Seek Complete
> Data Request

Uh, it'd be nice to know which devices these were related to, just to
limit confirm which device may still need nodma specified.

> 
> The messages following that show
> the disk geometry, so it's clear that
> they can get to the drive.
> 
> 
> Could the size of the disks be a problem ?

No.

> Machine runs Windows fine.

I've seen many a sick machine run Windows.  Windows doesn't put as much
of a strain on the machine, and Windows doesn't run DMA on CD/DVDs
normally.

> The Machine ran fine when it ran RedHat WS with a 2.4
> kernel.

Smaller kernel, lower performance, not as much strain on DMA.

> This must be a "Well - known problem" but I scanned
> the archive for last year and could not find similiar.

It was far more prevalent on 2.4.14 through 2.4.18 kernels, not so
much later.

----------------------------------------------------------------------
- Rick Stevens, Senior Systems Engineer     rstevens at vitalstream.com -
- VitalStream, Inc.                       http://www.vitalstream.com -
-                                                                    -
-  You know you've landed gear-up when it takes full power to taxi.  -
-                                                -- Chuck Yeager     -
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