Re: Problem with random.c and PPC

From: Oliver Xymoron (
Date: Fri Aug 16 2002 - 11:33:49 EST

On Thu, Aug 15, 2002 at 06:50:32PM -0700, H. Peter Anvin wrote:
> Followup to: <20020815210449.GA26993@opus.bloom.county>
> By author: Tom Rini <>
> In newsgroup:
> >
> > Ah, thanks. In that case, no. It doesn't look like the input-layer USB
> > keyboards contribute to entropy (but mice do), and I don't think the ADB
> > ones do. I'll take a crack at adding this to keyboards monday maybe.
> >
> Be careful... USB devices are *always* going to speak at the same
> place in the USB cycle... I believe that is 1 ms. Thus,
> submillisecond resolution is *not* random.

Currently not a problem for anyone except X86, as they'll only use HZ
resolution. But the same problem exists on regular mice and keyboards,
which are typically scanned for events at a fixed rate.

This is just the tip of the iceberg for problems with entropy
accounting. I've got some free time today, I'll try to clean up my
patches for this.

 "Love the dolphins," she advised him. "Write by W.A.S.T.E.." 
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