[Intel-gfx] [PATCH 1/2] drm/i915/vlv: Workaround a punit issue in DDR data rate for 1333.

[Lee, Chon Ming]

On 11/07 14:46, Ville Syrjälä wrote:
> On Thu, Nov 07, 2013 at 03:23:26PM +0800, Chon Ming Lee wrote:
> > For DDR data rate reporting by Punit in PUNIT_GPU_FREQ_STS, the actual
> > data encoding is 00b=800, 01b=1066, 10b=1333, 11b=1333.
> > 
> > Some premium VLV sku will get the DDR_DATA_RATE set as 11.  As a result,
> > the turbo frequency reporting will be incorrect without this workaround.
> 
> Does that mean that the original encoding we used was in fact correct,
> and the new one is not?
> 

The spec documents the encoding is 00b=800, 01b=1066, 10b=1333, 11b=invalid  

But after check with the punit owner, the 11b is refer to 1333 as well.  It is
not invalid anymore.

> > 
> > Signed-off-by: Chon Ming Lee <chon.ming.lee at intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_pm.c |    7 +------
> >  1 files changed, 1 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> > index a5778e5..13fb7f8 100644
> > --- a/drivers/gpu/drm/i915/intel_pm.c
> > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > @@ -5328,12 +5328,7 @@ static void valleyview_init_clock_gating(struct drm_device *dev)
> >  		dev_priv->mem_freq = 1333;
> >  		break;
> >  	case 3:
> > -		/*
> > -		 * Probably a BIOS/Punit bug, or a new platform we don't
> > -		 * support yet.
> > -		 */
> > -		WARN(1, "invalid DDR freq detected, assuming 800MHz\n");
> > -		dev_priv->mem_freq = 800;
> > +		dev_priv->mem_freq = 1333;
> >  		break;
> >  	}
> >  	DRM_DEBUG_DRIVER("DDR speed: %d MHz", dev_priv->mem_freq);
> > -- 
> > 1.7.7.6
> > 
> > _______________________________________________
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> > Intel-gfx at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> -- 
> Ville Syrjälä
> Intel OTC