[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]
Re: kern/34507: bge(4) doesn't contribute to the rnd pool
The following reply was made to PR kern/34507; it has been noted by GNATS.
From: Christoph Badura <bad%bsd.de@localhost>
Subject: Re: kern/34507: bge(4) doesn't contribute to the rnd pool
Date: Sun, 24 Feb 2008 14:45:36 +0100
On Sat, Feb 23, 2008 at 10:40:02AM +0000, Michael van Elst wrote:
> I also don't know what data in the driver could be considered
> random. The status word, which is used by other drivers, is almost
> always a constant when an interrupt occurs.
The data doesn't need to be random. rnd_add_uint32() doesn't use the
actual data. It is interested only in the jitter between the events.
I've looked at adding rnd(4) support for bge before. I gave up because
determining if the interrupt routine was called because of a interrupt
from the device was expensive and, IIRC, not trivial without layering
violations. However, this is necessary, because the interrupt vector is
often shared with other devices on the PCI bus (e.g. 8 other drivers on my
Main Index |
Thread Index |