where is kern.ca.da.no_6_byte?

Andre Guibert de Bruet andy at siliconlandmark.com
Sun Jul 20 10:49:44 PDT 2003


On Sun, 20 Jul 2003, Harald Schmalzbauer wrote:

> Andre Guibert de Bruet wrote:
> > On Sun, 20 Jul 2003, Harald Schmalzbauer wrote:
> >
> > > Kenneth D. Merry wrote:
> > > > > seems that this sysctl doesn't exist any more!
> > > > > Is there anything similar?
> > > >
> > > > It has been renamed:
> > > > kern.cam.da.%d.minimum_cmd_size
> > > >
> > > > Where %d is the unit number for the da(4) device.
> > >
> > > Thaks a lot! Where can I find such info? I looked via cvsweb
> > for scsi_da.c
> > > but couldn't find anything. Is it possible to list all kernel tunables?
> >
> > sysctl -a. You'll probably want to pipe it's output to your favorite
> > pager. "sysctl kern" will list just the entries in the kern MIB.
>
> OIC. It's not available until the device is pluged in, which makes it
> absolutely useless.
> When I plug it in the machine behaves abnormal, so I need to set it BEFORE
> connecting USB devices.
> Why has this tunable by default a value which makes the machine unstable by
> every umass I plug in which has no "qirk" entry? And if I look how many
> quirks there are I assume that almost every device needs no_6byte set.
> Why not make it default? Perhaps this would prevent criminal people from
> intentionally crashing servers when intruding my serverroom armed with
> dozends of USB devices;)

I don't mean to defend the current state of the USB stack not recovering
from errors and bad behavior, but ask yourself:

"Do I really want USB enabled on my servers?"

For most people, the answer is a resounding "No".

Food for thought.
Regards,

> Andre Guibert de Bruet | Enterprise Software Consultant >
> Silicon Landmark, LLC. | http://siliconlandmark.com/    >


More information about the freebsd-current mailing list