Re: hwrng on 82801EB/ER (ICH5/ICH5R) fails rngtest checks

[Michael Buesch <mb@bu3sch.de>]

On Thursday 27 July 2006 16:20, gmu 2k6 wrote:
> On 7/27/06, Michael Buesch <mb@bu3sch.de> wrote:
> > On Wednesday 26 July 2006 21:44, gmu 2k6 wrote:
> > > > But could you try the following patch on top of latest git?
> > > > It's just a random test, but I think it's worth trying.
> > > > Let's see if it works around the issue.
> > > >
> > > > Index: linux-2.6/drivers/char/hw_random/intel-rng.c
> > > > ===================================================================
> > > > --- linux-2.6.orig/drivers/char/hw_random/intel-rng.c   2006-06-27 17:48:13.000000000 +0200
> > > > +++ linux-2.6/drivers/char/hw_random/intel-rng.c        2006-07-26 17:27:03.000000000 +0200
> > > > @@ -104,9 +104,14 @@
> > > >         int err = -EIO;
> > > >
> > > >         hw_status = hwstatus_get(mem);
> > > > +       hw_status = hwstatus_set(mem, hw_status & ~INTEL_RNG_ENABLED);
> > > > +       hw_status = hwstatus_set(mem, hw_status | INTEL_RNG_ENABLED);
> > > > +#if 0
> > > > +       hw_status = hwstatus_get(mem);
> > > >         /* turn RNG h/w on, if it's off */
> > > >         if ((hw_status & INTEL_RNG_ENABLED) == 0)
> > > >                 hw_status = hwstatus_set(mem, hw_status | INTEL_RNG_ENABLED);
> > > > +#endif
> > > >         if ((hw_status & INTEL_RNG_ENABLED) == 0) {
> > > >                 printk(KERN_ERR PFX "cannot enable RNG, aborting\n");
> > > >                 goto out;
> > >
> > > well as it didn't work, are you sure it was not intended to be more like this:
> > > @@ -104,9 +104,14 @@
> > >        int err = -EIO;
> > >
> > >        hw_status = hwstatus_get(mem);
> > > +       hw_status = hwstatus_set(mem, hw_status & ~INTEL_RNG_ENABLED);
> > > +       hw_status = hwstatus_set(mem, hw_status | INTEL_RNG_ENABLED);
> > > +#if 0
> > >        /* turn RNG h/w on, if it's off */
> > >        if ((hw_status & INTEL_RNG_ENABLED) == 0)
> > >                hw_status = hwstatus_set(mem, hw_status | INTEL_RNG_ENABLED);
> > > +#endif
> > >        if ((hw_status & INTEL_RNG_ENABLED) == 0) {
> > >                printk(KERN_ERR PFX "cannot enable RNG, aborting\n");
> > >                goto out;
> > >
> > > ?
> >
> > I don't think that makes a difference to the generated code, does it?
> 
> I will test it now as you seem to be interested in the results.
> 
> actually I was just curious what sense it made to do
> hw_status = hwstatus_get(mem);
> twice, though I'm not informed about the semantics there so I could be wrong
> in interpreting the API on that level.

Look at the #if 0. The second hwstatus_get is not going to be compiled, anyway.

But Jan Beulich posted an interresting patch to lkml.
Please test it.
http://marc.theaimsgroup.com/?l=linux-kernel&m=115399953714650&q=raw

-- 
Greetings Michael.