Re: [PATCH 2/2] drm/i915: remove HBR2 from chv supported list

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Fri, Jul 31, 2015 at 11:32:53AM +0530, Sivakumar Thulasimani wrote:
> From: "Thulasimani,Sivakumar" <sivakumar.thulasimani@intel.com>
> 
> This patch removes 5.4Gbps from supported link rate for CHV since
> it is not supported in it.
> 
> Signed-off-by: Sivakumar Thulasimani <sivakumar.thulasimani@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_dp.c |    5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index d9fb7a8..4e53433 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -1186,8 +1186,9 @@ intel_dp_source_rates(struct drm_device *dev, const int **source_rates)
>  
>  	*source_rates = default_rates;
>  
> -	if (IS_SKYLAKE(dev) && INTEL_REVID(dev) <= SKL_REVID_B0)
> -		/* WaDisableHBR2:skl */
> +	/* WaDisableHBR2:skl */
> +	if ((IS_SKYLAKE(dev) && INTEL_REVID(dev) <= SKL_REVID_B0) ||
> +		IS_CHERRYVIEW(dev))
>  		return (DP_LINK_BW_2_7 >> 3) + 1;
>  	else if (INTEL_INFO(dev)->gen >= 8 ||
>  	    (IS_HASWELL(dev) && !IS_HSW_ULX(dev)))

I would suggest reordering this a bit. Something likle this perhaps:

/* WaDisableHBR2:skl */
if (IS_SKYLAKE && ...)
	return (DP_LINK_BW_2_7 >> 3) + 1;

if ((IS_HASWELL && !IS_HSW_ULX) || IS_BROADWELL || gen >= 9)
	return (DP_LINK_BW_5_4 >> 3) + 1;
else
	return (DP_LINK_BW_2_7 >> 3) + 1;

IMO that makes it easier to see exactly which platforms support
HBR2, and it keeps the SKL w/a separated neatly for easy removal in the
near future (I'm assuming we want to kill the w/a based on the fact that
it's for an early stepping).

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