Re: /proc/bus/pci odd behavior

Gerard Roudier (groudier@club-internet.fr)
Sat, 17 Oct 1998 18:32:21 +0200 (MET DST)


On Fri, 16 Oct 1998, Martin Mares wrote:

> Hello,
>
> > While digging through some of the /proc files, I stumbled across some
> > interesting behavior in /proc/bus/pci. This doesn't seem to be very
> > serious, as things recover just fine after a few seconds, and it only
> > works as root, but reading a file in /proc/bus/pci/00 on my system (09.0
> > in this case) causes my SCSI controller to flip.
>
> This is a known problem (already discussed in this list a week ago). Your
> SCSI card has configuration registers with side effects on reads and you are
> root, therefore /proc/bus/pci does exactly what it should do.

Martin, you _shall_ change either your documentation or your code or both
in a way that will prevent this feature from being a _trap_ that let users
break their systems.

BTW, I am still expecting from you the text of the PCI specifications, you
seemed to refer to, about device specific configuration space being
required to allow reads without side effect. It will not be a problem if
you didn't find this text, since I didn't find it too. Anyway, real
software must take into account real hardware.

Gerard.

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