Re: [PATCH 2/6] drm/i915/bdw: Add support for DRRS to switch RR

[Rodrigo Vivi <rodrigo.vivi@gmail.com>]

On Fri, Feb 13, 2015 at 2:03 AM, Ramalingam C <ramalingam.c@intel.com> wrote:
> From: Vandana Kannan <vandana.kannan@intel.com>
>
> For Broadwell, there is one instance of Transcoder MN values per transcoder.
> For dynamic switching between multiple refreshr rates, M/N values may be
> reprogrammed on the fly. Link N programming triggers update of all data and
> link M & N registers and the new M/N values will be used in the next frame
> that is output.
>
> V2: [By Ram]: intel_dp_set_m_n() is rewritten to accommodate
>         gen >= 8 [Rodrigo]
> V3: Coding style correction [Ram]
> V4: [By Ram] intel_dp_set_m_n modifications are moved into a
>         separate patch, retaining only DRRS related changes here [Rodrigo]
>
> Signed-off-by: Vandana Kannan <vandana.kannan@intel.com>
> Signed-off-by: Pradeep Bhat <pradeep.bhat@intel.com>
> Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_dp.c |   16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 868a07b..6ffbf57 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -4793,12 +4793,24 @@ static void intel_dp_set_drrs_state(struct drm_device *dev, int refresh_rate)
>                 return;
>         }
>
> -       if (INTEL_INFO(dev)->gen > 6 && INTEL_INFO(dev)->gen < 8) {
> +       if (INTEL_INFO(dev)->gen >= 8) {
> +               switch (index) {
> +               case DRRS_HIGH_RR:
> +                       intel_dp_set_m_n(intel_crtc, M1_N1);
> +                       break;
> +               case DRRS_LOW_RR:
> +                       intel_dp_set_m_n(intel_crtc, M2_N2);
> +                       break;
> +               case DRRS_MAX_RR:

Why to redirect this to an error insted making MAX = HIGH?

> +               default:
> +                       DRM_ERROR("Unsupported refreshrate type\n");
> +               }
> +       } else if (INTEL_INFO(dev)->gen > 6) {
>                 reg = PIPECONF(intel_crtc->config->cpu_transcoder);
>                 val = I915_READ(reg);
> +
>                 if (index > DRRS_HIGH_RR) {
>                         val |= PIPECONF_EDP_RR_MODE_SWITCH;
> -                       intel_dp_set_m_n(intel_crtc);
>                 } else {
>                         val &= ~PIPECONF_EDP_RR_MODE_SWITCH;
>                 }
> --
> 1.7.9.5
>
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-- 
Rodrigo Vivi
Blog: http://blog.vivi.eng.br
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