Understanding DMA/NoDMA options and fixes

[John Best]

-----Original Message-----
From: fedora-list-bounces at redhat.com
[mailto:fedora-list-bounces at redhat.com]On Behalf Of Paul Howarth
Sent: Tuesday, July 19, 2005 1:53 AM
To: For users of Fedora Core releases
Subject: Re: Understanding DMA/NoDMA options and fixes


On Mon, 2005-07-18 at 21:02 -0500, John Best wrote:
> I think I asked this before , but I am still not satisfied with the
> answer...
>
> I have had to boot with the nodma option since FC3...   I have not had
> issues doing this, but I wonder if I am getting the performance I should
> by disabling the dma option (I have seen posts that have pointed that
> nodma can reduce linux performance on some machines).   The question
> that I have not resolved is what can I do about it?????

The ide=nodma option is usually suggested as a workaround for mediacheck
problems during installation; systems installed that way will have the
same option configured in grub but it *may* not be necessary for normal
operation. Does your system work if you boot without that option?

Paul.
--
Paul Howarth <paul at city-fan.org>

Based on past experiences, no it does not boot correctly.. My problems did
not seem to be media check related.
Both the install boot and boots following install would hang at a particular
location ( I never was able to track down, but if I recall it was just near
or after the kernel load).  Using NoDMA corrected it and I have been using
it since FC3..(possibly back to fc2)  Once and a while I build a boot disk
(Using re-writable cd's) to check it out without the ide=nodma option and in
all cases appears to hang at a spot during the boot.

My thought was that if this is a hardware component/connection issue, I
could try to correct or possibly at least see which component (Disk drive or
cd ) was the culprit... Currently running with 2 HD (I think a west Dig 160G
and a Maxtor 40g)  and 1 CDRW (HP) and 1 CDROM (Generic).  Thinking there
may be jumpers that will enable/disable the appropriate issue causing dma
setting on the device.. (OR BOIS???)

Anyway, I may try to boot without the nodma option and see if I can track
down where it hangs up...If that might help with a firmer diagnosis.