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

[Ville Syrjälä]

On Thu, Nov 07, 2013 at 09:49:55PM +0800, Lee, Chon Ming wrote:
> 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  

There was another encoding in some older spec. And we just changed from
that to the current one.

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

OK. In that case:

Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

> 
> > > 
> > > 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
> > > 
> > > _______________________________________________
> > > Intel-gfx mailing list
> > > Intel-gfx at lists.freedesktop.org
> > > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > 
> > -- 
> > Ville Syrjälä
> > Intel OTC

-- 
Ville Syrjälä
Intel OTC