Re: [PATCH] drm/i915/bxt: Broxton doesn't use gen9 scaling for rps frequencies.

Bob Paauwe
2015-11-11T21:35:57Z

On Tue, 10 Nov 2015 11:04:22 +0200
Mika Kuoppala <mika.kuoppala@linux.intel.com> wrote:

> Bob Paauwe <bob.j.paauwe@intel.com> writes:
>
> > Signed-off-by: Bob Paauwe <bob.j.paauwe@intel.com>
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92768
> > ---
> > drivers/gpu/drm/i915/intel_pm.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> > index 647c0ff..fc5097f 100644
> > --- a/drivers/gpu/drm/i915/intel_pm.c
> > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > @@ -7138,7 +7138,7 @@ static int chv_freq_opcode(struct drm_i915_private *dev_priv, int val)
> >
> > int intel_gpu_freq(struct drm_i915_private *dev_priv, int val)
> > {
> > - if (IS_GEN9(dev_priv->dev))
> > + if (IS_GEN9(dev_priv->dev) && !IS_BROXTON(dev_priv->dev))
> > return (val * GT_FREQUENCY_MULTIPLIER) /
> > GEN9_FREQ_SCALER;
>
> Documentation disagrees with this patch. The units are 16.67Mhz
> thus we should use 50/3.
>
> -Mika

I'm not sure I trust the documentation in this case. Elsewhere, in
gen6_init_rps_frequencies() we use GEN9_FREQ_SCALER for SKL only, not for BXT.

I tried changing gen6_init_rps_frequencies() to use it for both SKL and
BXT but that didn't resolve the problem when running the ps_rps igt
test. So if we really should be using the 50/3 scale for BXT, there's
another bug somewhere.

>
> > else if (IS_CHERRYVIEW(dev_priv->dev))
> > return chv_gpu_freq(dev_priv, val);
> > @@ -7150,7 +7150,7 @@ int intel_gpu_freq(struct drm_i915_private *dev_priv, int val)
> >
> > int intel_freq_opcode(struct drm_i915_private *dev_priv, int val)
> > {
> > - if (IS_GEN9(dev_priv->dev))
> > + if (IS_GEN9(dev_priv->dev) && !IS_BROXTON(dev_priv->dev))
> > return (val * GEN9_FREQ_SCALER) / GT_FREQUENCY_MULTIPLIER;
> > else if (IS_CHERRYVIEW(dev_priv->dev))
> > return chv_freq_opcode(dev_priv, val);
> > --
> > 2.4.3
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx

--
--
Bob Paauwe
Bob.J.Paauwe@intel.com
IOTG / PED Software Organization
Intel Corp. Folsom, CA
(916) 356-6193