Subject: Re: freezing the scsi bus
To: der Mouse <mouse@Rodents.Montreal.QC.CA>
From: Manuel Bouyer <>
List: tech-kern
Date: 07/10/1999 16:47:35
On Fri, Jul 09, 1999 at 04:57:46PM -0400, der Mouse wrote:
> [...]
> I could do this via two ioctls (to freeze and unfreeze), except for the
> risk that the process will have to page something in off disk in order
> to unfreeeze the bus.  I could move it all into the kernel and obviate
> that risk, except for issues like having to exit X so that /dev/console
> actually does something.  (Trying to do it within X is too much hair;
> it would mean locking pieces of an indeterminate number of processes
> into core - and that doesn't even consider the problems of trying to
> figure out which processes need locking, or which pieces of those
> processes.)
> Thoughts, anyone?

FreeBSD does this by freesing for a defined amount of time (15s ...),
all is done in kernel. Would this be enouth ?
Detecting a key press in userland while the bus is looked is not reliable,
and doing it in kernel may not be easy (port dependant probably ...).

Manuel Bouyer <>