> -----Original Message-----
> From: Bartlomiej Zolnierkiewicz [mailto:bzolnier@gmail.com]
> Sent: Monday, February 05, 2007 7:09 AM
> To: Allen Martin
> Subject: Fwd: Nvidia cable detection problems (was [PATCH]
> amd74xx: don't configure udma mode higher than BIOS did)
>
> Hi Allen,
>
> Would it be possible to get some help on this issue?
>
> Thanks,
> Bart
>
> ---------- Forwarded message ----------
> From: Tejun Heo <htejun@gmail.com>
> Date: Feb 5, 2007 3:50 PM
> Subject: Re: Nvidia cable detection problems (was [PATCH] amd74xx:
> don't configure udma mode higher than BIOS did)
> To: Alan <alan@lxorguk.ukuu.org.uk>
> Cc:
bzolnier@gmail.com,
linux-ide@vger.kernel.org,
>
linux-kernel@vger.kernel.org
>
>
> Alan wrote:
> [--snip--]
> >> CK804 IDE, at least mine, reports 80c in a lot of cases where it
> >> shouldn't. I dunno the reason but it also makes drives confused
> >> about cable type. Maybe it has the wrong capacitor
> attached or something.
> >> This is A8N-E from ASUS, probably one of the popular ones
> using nf4.
> >
> > I take it this was how you came to find every cable related
> bug while
> > trying to work out what was going on ?
>
> Yeap, pretty much. I thought fixing drive side cable
> detection would fix it, but hell no.
>
> >> When that happens, libata EH does its job and slows the
> interface to
> >> udma33 after quite a few error messages. On IDE, if this happens,
> >> the drive is put into PIO mode making the machine painful to use.
> >
> > No the IDE layer does DMA changedown fine, well apart from all the
> > error/timer races in the old IDE code.
>
> I dunno. It always ended up in PIO mode in my case. I can
> post the log if necessary.
>
> [--snip--]
> >> I agree with you that this is a hack and ugly as hell. I
> don't like
> >> it either, but it solves an existing problem which could have and
> >> possibly will hit many users. So, I think this problem should at
> >> least be verified. If it's just my BIOS/motherboard
> that's crazy, I
> >> have no problem forgetting about this.
> >
> > It certainly seems to be Nvidia specific, so perhaps Nvidia can
> > provide more details on the Nforce4 cable detection ? As
> with a lot of
> > Nvidia stuff there was much reverse engineering involved in the
> > original code base.
>
> Hmmm... Anyone happen to have working nvidia contact?
>
> > And if its a specific board or couple of boards then we
> should perhaps
> > use DMI to match them specifically.
> >
> >> So, anyone with CK804 (a.k.a NF4) up for some testing?
> >
> > If it still goes I've got a rather iffy NF3 but not an NF4 handy.
>
> Yeah, please. If I connect a hdd at the end of 40c cable and
> leaving the middle connector empty, the 80c bit is always one
> and the drive says it's 80c cable while the BIOS configured
> mode is correctly udma33. This is the same for SAMSUNG
> SP0802N, Maxtor 91301U3 and HITACHI_DK23BA-20.
>
> --
> tejun
>
