On Tue, 2009-10-20 at 16:52 +0200, Witold Baryluk wrote:
> On 10-19 03:07, Ben Hutchings wrote:
> > On Mon, 2009-03-23 at 18:36 +0100, root wrote:
> > > Package: linux-image-2.6.26-1-686
> > > Version: 2.6.26-13lenny2
> > > Severity: important
> >
> > > So it looks like there is some blacklist (in piix modules) for this server board,
> > > and kernel uses generic (and non-dma) module for ide. But with 2.6.18-686 it was working.
> >
> > However, this blacklist has been present since before Linux 2.6.12, so
> > it doesn't really explain the change.
> Hmm, i checked in git, and you are right, it is for long time (with small modification).
> But as I already stated in Etch's 2.6.18-686 dmesg doesn't containt,
> messages which are in 2.6.26. But according to sources they should be
> excetly the same. So for some reason (API interfaces, PCI read procedures)
> it is not blacklisted on older kernel.
I looked more closely at the changelog and found that although the
blacklist has been present for a long time, there was also a bug that
meant that it did not have the intended effect of disabling DMA.
This was fixed by this change in Linux 2.6.20:
commit 44854add66811124a5667466245b6824f751143a
Author: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Date: Fri Dec 29 16:49:26 2006 -0800
[PATCH] PIIX/SLC90E66: PIO mode fallback fix
[...]
> Can it be "false positive"?
[...]
Since you say that IDE DMA was reliable under 2.6.18, it seems that you
have found a false positive. But until we know exactly which
configurations of the 450NX do have reliable IDE DMA, we cannot
reasonably change this blacklist.
If you want to get this fixed in the kernel rather than by overriding it
with hdparm, please test Linux 2.6.31 from the Debian experimental
repository. If that still has the problem, you can report it upstream
at <http://bugzilla.kernel.org> and hopefully get an IDE maintainer to
investigate it.
Ben.
--
Ben Hutchings
Everything should be made as simple as possible, but not simpler.
- Albert Einstein
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