[Intel-gfx] [PATCH] drm/i915: vlv: clamp minimum RPS frequency to what Punit allows

[Imre Deak]

On Fri, 2014-12-05 at 23:16 +0200, Imre Deak wrote:
> On Fri, 2014-12-05 at 21:58 +0100, Daniel Vetter wrote:
> > On Thu, Dec 04, 2014 at 06:39:35PM +0200, Imre Deak wrote:
> > > As described in the code comment, I couldn't set the minimum RPS
> > > frequency on my BYT-M B0 to the minimum allowed as reported by Punit.
> > > Fix this by clamping the minimum value to the first one that was
> > > accepted on my machine. This fixes at least the pm_rpm basic-api and
> > > min-max-config subtests.
> > > 
> > > Testcase: igt/pm_rps
> > > Signed-off-by: Imre Deak <imre.deak at intel.com>
> > 
> > Isn't there a bugzilla for this, too?
> 
> I didn't check this:/ There are some that may be fixed, or at least
> partially fixed. I just list all pm_rps bugs here, they are all worth
> rechecking imo, although the non-VLV/CHV ones are less likely to be
> related:
> 
> Reference: https://bugs.freedesktop.org/show_bug.cgi?id=80704
> Reference: https://bugs.freedesktop.org/show_bug.cgi?id=86654
> Reference: https://bugs.freedesktop.org/show_bug.cgi?id=86363
> Reference: https://bugs.freedesktop.org/show_bug.cgi?id=84896
> Reference: https://bugs.freedesktop.org/show_bug.cgi?id=77869

Sorry, I meant the above for the 3 igt patches actually. For this
particular one I haven't found any ticket.

> 
> 
> > -Daniel
> > 
> > > ---
> > >  drivers/gpu/drm/i915/intel_pm.c | 12 +++++++++++-
> > >  1 file changed, 11 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> > > index 45c786f..7a1112f 100644
> > > --- a/drivers/gpu/drm/i915/intel_pm.c
> > > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > > @@ -5039,7 +5039,17 @@ static int valleyview_rps_rpe_freq(struct drm_i915_private *dev_priv)
> > >  
> > >  static int valleyview_rps_min_freq(struct drm_i915_private *dev_priv)
> > >  {
> > > -	return vlv_punit_read(dev_priv, PUNIT_REG_GPU_LFM) & 0xff;
> > > +	u32 val;
> > > +
> > > +	val = vlv_punit_read(dev_priv, PUNIT_REG_GPU_LFM) & 0xff;
> > > +	/*
> > > +	 * According to the BYT Punit GPU turbo HAS 1.1.6.3 the minimum value
> > > +	 * for the minimum frequency in GPLL mode is 0xc1. Contrary to this on
> > > +	 * a BYT-M B0 the above register contains 0xbf. Moreover when setting
> > > +	 * a frequency Punit will not allow values below 0xc0. Clamp it 0xc0
> > > +	 * to make sure it matches what Punit accepts.
> > > +	 */
> > > +	return max_t(u32, val, 0xc0);
> > >  }
> > >  
> > >  /* Check that the pctx buffer wasn't move under us. */
> > > -- 
> > > 1.8.4
> > > 
> > > _______________________________________________
> > > Intel-gfx mailing list
> > > Intel-gfx at lists.freedesktop.org
> > > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > 
>