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

[gmu 2k6]

On 7/26/06, Michael Buesch <mb@xxxxxxxxx> wrote:
> On Wednesday 26 July 2006 16:52, gmu 2k6 wrote:
> > On 7/26/06, Michael Buesch <mb@xxxxxxxxx> wrote:
> > > On Wednesday 26 July 2006 16:21, gmu 2k6 wrote:
> > > > it just outputs this and stops with 2.6.18-rc2-HEAD (see dmesg for hashcode or
> > > > whatever that is which is appended as localversion)
> > > >
> > > > svn:~# hexdump /dev/hwrng
> > > > 0000000 ffff ffff ffff ffff ffff ffff ffff ffff
> > > > *
> > > >
> > > > with 2.6.17.6:
> > > > svn:~# hexdump /dev/hwrng
> > > > 0000000 ffff ffff ffff ffff ffff ffff ffff ffff
> > > > *
> > > >
> > > > this was without any rng-tools installed and no rngd running of course.
> > >
> > > Hm, so I would say the hardware either broken, or intel
> > > changed the way to read the random data from it. But I doubt they
> > > would change something like this on the ICH5.
> > >
> > > Who wrote the ICH driver? Jeff? Philipp?
> > > What do you think?
> >
> > IIRC it was Jeff.
>
> "What do you think?" was more a question to Jeff or Philipp ;)
>
>
>
> 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;

?
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