[Intel-gfx] [PATCH 5/10] drm/i915/bdw: Add support for DRRS to switch RR

[Rodrigo Vivi]

On Fri, Jan 9, 2015 at 12:56 PM, Vandana Kannan
<vandana.kannan at intel.com> wrote:
> 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.
>
> Signed-off-by: Vandana Kannan <vandana.kannan at intel.com>
> Signed-off-by: Pradeep Bhat <pradeep.bhat at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_display.c |  9 +++------
>  drivers/gpu/drm/i915/intel_dp.c      | 15 ++++++++++++++-
>  drivers/gpu/drm/i915/intel_drv.h     |  3 +++
>  3 files changed, 20 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index a03955d..25596ca 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -88,9 +88,6 @@ static int intel_framebuffer_init(struct drm_device *dev,
>                                   struct drm_i915_gem_object *obj);
>  static void i9xx_set_pipeconf(struct intel_crtc *intel_crtc);
>  static void intel_set_pipe_timings(struct intel_crtc *intel_crtc);
> -static void intel_cpu_transcoder_set_m_n(struct intel_crtc *crtc,
> -                                        struct intel_link_m_n *m_n,
> -                                        struct intel_link_m_n *m2_n2);
>  static void ironlake_set_pipeconf(struct drm_crtc *crtc);
>  static void haswell_set_pipeconf(struct drm_crtc *crtc);
>  static void intel_set_pipe_csc(struct drm_crtc *crtc);
> @@ -5795,9 +5792,9 @@ static void intel_pch_transcoder_set_m_n(struct intel_crtc *crtc,
>         I915_WRITE(PCH_TRANS_LINK_N1(pipe), m_n->link_n);
>  }
>
> -static void intel_cpu_transcoder_set_m_n(struct intel_crtc *crtc,
> -                                        struct intel_link_m_n *m_n,
> -                                        struct intel_link_m_n *m2_n2)
> +void intel_cpu_transcoder_set_m_n(struct intel_crtc *crtc,
> +                                struct intel_link_m_n *m_n,
> +                                struct intel_link_m_n *m2_n2)
>  {
>         struct drm_device *dev = crtc->base.dev;
>         struct drm_i915_private *dev_priv = dev->dev_private;
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index ca89e59..85a029e 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -4802,7 +4802,20 @@ 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);
> +                       break;
> +               case DRRS_LOW_RR:
> +                       intel_cpu_transcoder_set_m_n(intel_crtc,

I didn't like this mix of intel_dp_set and intel_cpu set when
intel_dp_set calls cpu set only when it doesn't have pch...
It seems at least strange.

Maybe change intel_dp_set_m_n to support different sets...

> +                                       &intel_crtc->config.dp_m2_n2, NULL);

Also didn't understand why sending m2_n2 on m1_n1 and NULL on m2_n2.

Is there a way to change that function to support different ways
instead of doing this?

> +                       break;
> +               case DRRS_MAX_RR:
> +               default:
> +                       break;
> +               }
> +       } else if (INTEL_INFO(dev)->gen > 6) {
>                 reg = PIPECONF(intel_crtc->config.cpu_transcoder);
>                 val = I915_READ(reg);
>                 if (index > DRRS_HIGH_RR) {
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 17f168a..f5846cf 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -953,6 +953,9 @@ void hsw_disable_pc8(struct drm_i915_private *dev_priv);
>  void intel_dp_get_m_n(struct intel_crtc *crtc,
>                       struct intel_crtc_config *pipe_config);
>  void intel_dp_set_m_n(struct intel_crtc *crtc);
> +void intel_cpu_transcoder_set_m_n(struct intel_crtc *crtc,
> +                                struct intel_link_m_n *m_n,
> +                                struct intel_link_m_n *m2_n2);
>  int intel_dotclock_calculate(int link_freq, const struct intel_link_m_n *m_n);
>  void
>  ironlake_check_encoder_dotclock(const struct intel_crtc_config *pipe_config,
> --
> 2.0.1
>
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-- 
Rodrigo Vivi
Blog: http://blog.vivi.eng.br