Re: Testers for OpenBSD & NetBSD needed
Frederick Page <fpage@thebetteros.oche.de> wrote:
> >>> Aug 19 18:39:45 thebetteros /bsd: cd0: transfer error, downgrading to
> >>> DMA mode 2
>
> >Your problem is caused by a OpenBSD kernel bug. The kernel does not
> >handle odd DMA counts for ATA correctly.
>
> Are you sure it's a kernel-bug? (Please see below).
I am very sure.
ATA is a 16 bit system, so transfering an odd number of bytes is a bit tricky.
In your case, READ FULL TOC did try to transfer an odd number of bytes
and you observe a timeout. This is exactly what I would expect for a broken
implementation.....
> >If you install cdda2wav suid root and call it as non root user, does
> >it work?
>
> To my total astonishment: YES. After suid it also works as root!
What you write is the complete contrary to what I like to know.
I like to know whether it works ad _non_ root after it has been
installed suid root.
> -r-sr-xr-x 1 root bin 261K Aug 19 18:18 /usr/local/bin/cdda2wav
>
> >In order to avoid the Kernel bug from preventing you to do the test,
> >check the number of tracks on the CD. It it was a CD with an even
> >number of tracks, use one with an odd number of tracks or vice versa.
>
> Did that a couple of times, but the number of tracks seems to be
> irrelevant. After suid'ing cdda2wav it works with each and every CD
> now, as root and as fpage.
OK, now you write what I like to know....
> I'm totally confused about what might be going on here :-(
Did you do a cold start of the machine to make sure that there is DMA again?
It may be thye the PIO implementation does odd byte transfers correctly....
Jörg
--
EMail:joerg@schily.isdn.cs.tu-berlin.de (home) Jörg Schilling D-13353 Berlin
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