On Thu, Oct 25, 2018 at 09:49:40PM -0700, Anusha Srivatsa wrote:
> Add a crtc state for FEC. Currently, the state
> is determined by platform, DP and DSC being
> enabled. Moving forward we can use the state
> to have error correction on other scenarios too
> if needed.
>
> Suggested-by: Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx>
> Cc: Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx>
> Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
> Cc: Manasi Navare <manasi.d.navare@xxxxxxxxx>
> Signed-off-by: Anusha Srivatsa <anusha.srivatsa@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/intel_dp.c | 22 ++++++++++++++++++++++
> drivers/gpu/drm/i915/intel_drv.h | 3 +++
> 2 files changed, 25 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index cfcef9e4b5d9..4776ce6f2174 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -2045,6 +2045,23 @@ intel_dp_compute_link_config_fast(struct intel_dp *intel_dp,
> return false;
> }
>
> +static bool intel_dp_can_fec(struct intel_dp *intel_dp,
> + struct intel_crtc_state *pipe_config)
I would prefer naming it as intel_dp_supports_fec since as per Ville's feedback
on adding helper function for DSC that will be called intel_dp_supports_dsc
> +{
> + struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
You dont need dig_port, you can obtain dev_priv from intel_dp directly:
struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
> + struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
> + if (INTEL_GEN(dev_priv) < 11 || intel_dp_is_edp(intel_dp))
> + return false;
> +
> + /* On Gen 11, FEC is Supported Only for DP SST modes.
> + * Let us start by enabling FEC for Compressed streams.
> + */
Where is the check for sink FEC support?
> + if (pipe_config->dsc_params.compression_enable)
> + return true;
I think this logic also looks reversed. The compression_enable state should
be set based on whether can_fec is true and not the vice versa.
IMHO, can_fec is decided solely on the platform support.
Infact since can_fec or fec_support solely depends on platform and sink FEC support,
we dont need a can_fec state , that can just be obtained using a helper
intel_dp_supports_fec() which will check platform support and sink support.
Now if we are saying that we want to enable fec based on mode, then we need fec_enable
state in crtc and that can be set if intel_dp_supports_fec and for now only if compression_en
is set.
Jani, Ville what are your thoughts on this?
> + else
> + return false;
You can swap these and have false earlier and avoid else
Just return true at the end.
Manasi
> +
> +}
> static bool intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
> struct intel_crtc_state *pipe_config,
> struct link_config_limits *limits)
> @@ -2129,6 +2146,11 @@ static bool intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
> pipe_config->dsc_params.compressed_bpp,
> pipe_config->dsc_params.slice_count);
>
> + /* For DP 1.4, Enable DSC if FEC can be configured */
> + pipe_config->can_fec = intel_dp_can_fec(intel_dp, pipe_config);
> + if (!pipe_config->can_fec)
> + return false;
> +
> return true;
> }
>
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 9a94c6544bf5..9dac242ead12 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -940,6 +940,9 @@ struct intel_crtc_state {
> u8 slice_count;
> } dsc_params;
> struct drm_dsc_config dp_dsc_cfg;
> +
> + /* Forward Error correction State */
> + bool can_fec;
> };
>
> struct intel_crtc {
> --
> 2.17.1
>
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