[Intel-gfx] [PATCH 9/9] drm/i915/dsi: add support for DSC

[Kulkarni, Vandita]

> -----Original Message-----
> From: Jani Nikula <jani.nikula at intel.com>
> Sent: Friday, November 8, 2019 9:10 PM
> To: intel-gfx at lists.freedesktop.org
> Cc: Kulkarni, Vandita <vandita.kulkarni at intel.com>; Navare, Manasi D
> <manasi.d.navare at intel.com>; ville.syrjala at linux.intel.com; Nikula, Jani
> <jani.nikula at intel.com>
> Subject: [PATCH 9/9] drm/i915/dsi: add support for DSC
> 
> Enable DSC for DSI, if specified in VBT.
> 
> This is now excessively dynamic, being enabled at compute config. I don't
> expect us to need to switch between DSC and non-DSC for the same panel.
> Cargo culting the DP DSC shows.
> 
> Mode valid lacks a sensible implementation, as does get config.
> 
> Signed-off-by: Jani Nikula <jani.nikula at intel.com>
> ---
>  drivers/gpu/drm/i915/display/icl_dsi.c | 75 ++++++++++++++++++++++++--
>  1 file changed, 72 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/icl_dsi.c
> b/drivers/gpu/drm/i915/display/icl_dsi.c
> index 8eb2d7f29c82..823dbd9d4d06 100644
> --- a/drivers/gpu/drm/i915/display/icl_dsi.c
> +++ b/drivers/gpu/drm/i915/display/icl_dsi.c
> @@ -34,6 +34,7 @@
>  #include "intel_ddi.h"
>  #include "intel_dsi.h"
>  #include "intel_panel.h"
> +#include "intel_vdsc.h"
> 
>  static inline int header_credits_available(struct drm_i915_private *dev_priv,
>  					   enum transcoder dsi_trans)
> @@ -1050,6 +1051,9 @@ static void gen11_dsi_pre_enable(struct
> intel_encoder *encoder,
>  	/* step5: program and powerup panel */
>  	gen11_dsi_powerup_panel(encoder);
> 
> +	/* FIXME: location? */
> +	intel_dsc_enable(encoder, pipe_config);
> +
>  	/* step6c: configure transcoder timings */
>  	gen11_dsi_set_transcoder_timings(encoder, pipe_config);
> 
> @@ -1211,6 +1215,13 @@ static void gen11_dsi_disable(struct
> intel_encoder *encoder,
>  	gen11_dsi_disable_io_power(encoder);
>  }
> 
> +static enum drm_mode_status gen11_dsi_mode_valid(struct
> drm_connector *connector,
> +						 struct drm_display_mode
> *mode)
> +{
> +	/* FIXME: DSC? */
> +	return intel_dsi_mode_valid(connector, mode); }
> +
>  static void gen11_dsi_get_timings(struct intel_encoder *encoder,
>  				  struct intel_crtc_state *pipe_config)  { @@ -
> 1258,6 +1269,56 @@ static void gen11_dsi_get_config(struct intel_encoder
> *encoder,
>  	pipe_config->pipe_bpp = bdw_get_pipemisc_bpp(crtc);  }
> 
> +static int gen11_dsi_dsc_compute_config(struct intel_encoder *encoder,
> +					struct intel_crtc_state *pipe_config,
> +					struct drm_connector_state
> *conn_state) {
> +	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> +	struct drm_dsc_config *vdsc_cfg = &pipe_config->dsc.config;
> +	struct drm_display_mode *adjusted_mode = &pipe_config-
> >hw.adjusted_mode;
> +	int dsc_max_bpc = INTEL_GEN(dev_priv) >= 12 ? 12 : 10;
> +	bool use_dsc;
> +	int ret;
> +
> +	dsc_max_bpc = min_t(int, dsc_max_bpc, conn_state-
> >max_requested_bpc);
> +
> +	use_dsc = intel_bios_get_dsc_params(encoder, pipe_config,
> dsc_max_bpc);
> +	if (!use_dsc)
> +		return 0;
> +
> +	if (pipe_config->pipe_bpp < 8 * 3)
> +		return -EINVAL;
> +
> +	if (adjusted_mode->crtc_clock > dev_priv->max_cdclk_freq) {
> +		if (pipe_config->dsc.slice_count > 1) {
> +			pipe_config->dsc.dsc_split = true;
> +		} else {
> +			DRM_DEBUG_KMS("Cannot split stream to use 2
> VDSC instances\n");
> +			return -EINVAL;
> +		}
> +	}
> +
> +	vdsc_cfg->convert_rgb = false;
> +
> +	ret = intel_dsc_compute_params(encoder, pipe_config);
> +	if (ret)
> +		return ret;
> +
> +	/* DSI specific sanity checks on the common code */
> +	WARN_ON(vdsc_cfg->vbr_enable);
> +	WARN_ON(vdsc_cfg->pic_width % vdsc_cfg->slice_width);
> +	WARN_ON(vdsc_cfg->slice_height < 8);
> +	WARN_ON(vdsc_cfg->pic_height % vdsc_cfg->slice_height);
> +
> +	ret = drm_dsc_compute_rc_parameters(vdsc_cfg);
> +	if (ret)
> +		return ret;
> +
> +	pipe_config->dsc.compression_enable = true;
> +
As per the spec, I see that it asks us to program horizontal timings in video mode and use the compressed frequency ratio like burst mode, but it is a bit ambiguous if it is talking about non-burst mode.

We will have to add htotal, hsync_start and hsync_end calculation, if yes.

Thanks,
Vandita
> +	return 0;
> +}
> +
>  static int gen11_dsi_compute_config(struct intel_encoder *encoder,
>  				    struct intel_crtc_state *pipe_config,
>  				    struct drm_connector_state *conn_state)
> @@ -1286,14 +1347,22 @@ static int gen11_dsi_compute_config(struct
> intel_encoder *encoder,
>  	pipe_config->clock_set = true;
>  	pipe_config->port_clock = intel_dsi_bitrate(intel_dsi) / 5;
> 
> +	if (gen11_dsi_dsc_compute_config(encoder, pipe_config,
> conn_state))
> +		DRM_DEBUG_KMS("Attempting to use DSC failed\n");
> +
>  	return 0;
>  }
> 
>  static void gen11_dsi_get_power_domains(struct intel_encoder *encoder,
>  					struct intel_crtc_state *crtc_state)  {
> -	get_dsi_io_power_domains(to_i915(encoder->base.dev),
> -				 enc_to_intel_dsi(&encoder->base));
> +	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> +
> +	get_dsi_io_power_domains(i915, enc_to_intel_dsi(&encoder-
> >base));
> +
> +	if (crtc_state->dsc.compression_enable)
> +		intel_display_power_get(i915,
> +
> 	intel_dsc_power_domain(crtc_state));
>  }
> 
>  static bool gen11_dsi_get_hw_state(struct intel_encoder *encoder, @@ -
> 1360,7 +1429,7 @@ static const struct drm_connector_funcs
> gen11_dsi_connector_funcs = {
> 
>  static const struct drm_connector_helper_funcs
> gen11_dsi_connector_helper_funcs = {
>  	.get_modes = intel_dsi_get_modes,
> -	.mode_valid = intel_dsi_mode_valid,
> +	.mode_valid = gen11_dsi_mode_valid,
>  	.atomic_check = intel_digital_connector_atomic_check,
>  };
> 
> --
> 2.20.1