[Intel-gfx] [PATCH v2] drm/i915: use lower aux clock divider on non-ULT HSW

[Paulo Zanoni]

Hi

2013/4/9 Jani Nikula <jani.nikula at intel.com>:
> Workaround to avoid intermittent aux channel failures, per spec change.
>
> v2: Don't mess with cpu dp aux divider (Paulo Zanoni)
>
> Signed-off-by: Jani Nikula <jani.nikula at intel.com>
>
> ---
>
> Untested.
> ---
>  drivers/gpu/drm/i915/intel_dp.c |    8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 482b5e5..f8474d1 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -353,10 +353,14 @@ intel_dp_aux_ch(struct intel_dp *intel_dp,
>                         aux_clock_divider = 200; /* SNB & IVB eDP input clock at 400Mhz */
>                 else
>                         aux_clock_divider = 225; /* eDP input clock at 450Mhz */
> -       } else if (HAS_PCH_SPLIT(dev))
> +       } else  if (dev_priv->pch_id == INTEL_PCH_LPT_DEVICE_ID_TYPE) {

There's a space and a tab between "else" and "if", but I guess Daniel
will fix this :)

Reviewed-by: Paulo Zanoni <paulo.r.zanoni at intel.com>

> +               /* Workaround for non-ULT HSW */
> +               aux_clock_divider = 74;
> +       } else if (HAS_PCH_SPLIT(dev)) {
>                 aux_clock_divider = DIV_ROUND_UP(intel_pch_rawclk(dev), 2);
> -       else
> +       } else {
>                 aux_clock_divider = intel_hrawclk(dev) / 2;
> +       }
>
>         if (IS_GEN6(dev))
>                 precharge = 3;
> --
> 1.7.10.4
>



--
Paulo Zanoni