Re: [PATCH] drm/i915/xe3lpd: Prune modes for YUV420

["Nautiyal, Ankit K" <ankit.k.nautiyal@intel.com>]

On 6/20/2025 2:55 PM, Suraj Kandpal wrote:
> We only support resolution up to 4k for single pipe when using
> YUV420 format so we prune these modes and restrict the plane size
> at src. This is because pipe scaling will not support YUV420 scaling
> for hwidth > 4096.
>
> --v2
> -Use output format to check [Ville]
> -Add Bspec references
> -Modify commit messge to point to why this is needed
>
> --v3
> -Use a function skl_scaler_mode_valid which is routed throug
> intel_pfit_mode_valid [Ville]
> -Combine the check conditons [Jonathan]
>
> --v4
> -mode_valid functions should return drm_mode_status [Jani]
>
> Bspec: 49247, 50441
> Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
> Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com> #v2
> ---
>   drivers/gpu/drm/i915/display/intel_dp.c   | 11 ++++++++---
>   drivers/gpu/drm/i915/display/intel_hdmi.c |  4 ++++
>   drivers/gpu/drm/i915/display/intel_pfit.c | 11 +++++++++++
>   drivers/gpu/drm/i915/display/intel_pfit.h | 12 +++++++++++-
>   drivers/gpu/drm/i915/display/skl_scaler.c | 16 ++++++++++++++++
>   drivers/gpu/drm/i915/display/skl_scaler.h | 12 ++++++++++++
>   6 files changed, 62 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 277b40b13948..f10650d79663 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -1418,6 +1418,7 @@ intel_dp_mode_valid(struct drm_connector *_connector,
>   	struct intel_display *display = to_intel_display(_connector->dev);
>   	struct intel_connector *connector = to_intel_connector(_connector);
>   	struct intel_dp *intel_dp = intel_attached_dp(connector);
> +	enum intel_output_format sink_format, output_format;
>   	const struct drm_display_mode *fixed_mode;
>   	int target_clock = mode->clock;
>   	int max_rate, mode_rate, max_lanes, max_link_clock;
> @@ -1451,6 +1452,13 @@ intel_dp_mode_valid(struct drm_connector *_connector,
>   						     mode->hdisplay, target_clock);
>   	max_dotclk *= num_joined_pipes;
>   
> +	sink_format = intel_dp_sink_format(connector, mode);
> +	output_format = intel_dp_output_format(connector, sink_format);
> +
> +	status = intel_pfit_mode_valid(display, mode, output_format, num_joined_pipes);
> +	if (status != MODE_OK)
> +		return status;
> +
>   	if (target_clock > max_dotclk)
>   		return MODE_CLOCK_HIGH;
>   
> @@ -1466,11 +1474,8 @@ intel_dp_mode_valid(struct drm_connector *_connector,
>   					   intel_dp_mode_min_output_bpp(connector, mode));
>   
>   	if (intel_dp_has_dsc(connector)) {
> -		enum intel_output_format sink_format, output_format;
>   		int pipe_bpp;
>   
> -		sink_format = intel_dp_sink_format(connector, mode);
> -		output_format = intel_dp_output_format(connector, sink_format);
>   		/*
>   		 * TBD pass the connector BPC,
>   		 * for now U8_MAX so that max BPC on that platform would be picked
> diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c b/drivers/gpu/drm/i915/display/intel_hdmi.c
> index 9961ff259298..03045d188817 100644
> --- a/drivers/gpu/drm/i915/display/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
> @@ -2053,6 +2053,10 @@ intel_hdmi_mode_valid(struct drm_connector *_connector,
>   	else
>   		sink_format = INTEL_OUTPUT_FORMAT_RGB;
>   
> +	status = intel_pfit_mode_valid(display, mode, sink_format, 0);
> +	if (status != MODE_OK)
> +		return status;
> +
>   	status = intel_hdmi_mode_clock_valid(&connector->base, clock, has_hdmi_sink, sink_format);
>   	if (status != MODE_OK) {
>   		if (ycbcr_420_only ||
> diff --git a/drivers/gpu/drm/i915/display/intel_pfit.c b/drivers/gpu/drm/i915/display/intel_pfit.c
> index 13541be4d6df..68539e7c2a24 100644
> --- a/drivers/gpu/drm/i915/display/intel_pfit.c
> +++ b/drivers/gpu/drm/i915/display/intel_pfit.c
> @@ -14,6 +14,7 @@
>   #include "intel_lvds_regs.h"
>   #include "intel_pfit.h"
>   #include "intel_pfit_regs.h"
> +#include "skl_scaler.h"
>   
>   static int intel_pch_pfit_check_dst_window(const struct intel_crtc_state *crtc_state)
>   {
> @@ -546,6 +547,16 @@ static int gmch_panel_fitting(struct intel_crtc_state *crtc_state,
>   	return intel_gmch_pfit_check_timings(crtc_state);
>   }
>   
> +enum drm_mode_status
> +intel_pfit_mode_valid(struct intel_display *display,
> +		      const struct drm_display_mode *mode,
> +		      enum intel_output_format output_format,
> +		      int num_joined_pipes)
> +{
> +	return skl_scaler_mode_valid(display, mode, output_format,
> +				     num_joined_pipes);
> +}
> +
>   int intel_pfit_compute_config(struct intel_crtc_state *crtc_state,
>   			      const struct drm_connector_state *conn_state)
>   {
> diff --git a/drivers/gpu/drm/i915/display/intel_pfit.h b/drivers/gpu/drm/i915/display/intel_pfit.h
> index ef34f9b49d09..2f075748a34e 100644
> --- a/drivers/gpu/drm/i915/display/intel_pfit.h
> +++ b/drivers/gpu/drm/i915/display/intel_pfit.h
> @@ -6,8 +6,14 @@
>   #ifndef __INTEL_PFIT_H__
>   #define __INTEL_PFIT_H__
>   
> +#include <linux/types.h>
> +
> +enum drm_mode_status;
> +struct drm_display_mode;
>   struct drm_connector_state;
>   struct intel_crtc_state;
> +struct intel_display;
> +enum intel_output_format;
>   
>   int intel_pfit_compute_config(struct intel_crtc_state *crtc_state,
>   			      const struct drm_connector_state *conn_state);
> @@ -17,5 +23,9 @@ void ilk_pfit_get_config(struct intel_crtc_state *crtc_state);
>   void i9xx_pfit_enable(const struct intel_crtc_state *crtc_state);
>   void i9xx_pfit_disable(const struct intel_crtc_state *old_crtc_state);
>   void i9xx_pfit_get_config(struct intel_crtc_state *crtc_state);
> -
> +enum drm_mode_status
> +intel_pfit_mode_valid(struct intel_display *display,
> +		      const struct drm_display_mode *mode,
> +		      enum intel_output_format output_format,
> +		      int num_joined_pipes);
>   #endif /* __INTEL_PFIT_H__ */
> diff --git a/drivers/gpu/drm/i915/display/skl_scaler.c b/drivers/gpu/drm/i915/display/skl_scaler.c
> index d77798499c57..b8193ebf0772 100644
> --- a/drivers/gpu/drm/i915/display/skl_scaler.c
> +++ b/drivers/gpu/drm/i915/display/skl_scaler.c
> @@ -134,6 +134,22 @@ static void skl_scaler_max_dst_size(struct intel_crtc *crtc,
>   	}
>   }
>   
> +enum drm_mode_status
> +skl_scaler_mode_valid(struct intel_display *display,
> +		      const struct drm_display_mode *mode,
> +		      enum intel_output_format output_format,
> +		      int num_joined_pipes)
> +{
> +	if (num_joined_pipes < 2 && output_format == INTEL_OUTPUT_FORMAT_YCBCR420) {
> +		if (DISPLAY_VER(display) >= 14 &&
> +		    mode->hdisplay > 4096) {


Lets use skl_scaler_max_src_size to get the the max src width, that the 
scaler supports for a given platform.

Compare max_w  with mode->hdisplay.


Regards,

Ankit

> +			return MODE_NO_420;
> +		}
> +	}
> +
> +	return MODE_OK;
> +}
> +
>   static int
>   skl_update_scaler(struct intel_crtc_state *crtc_state, bool force_detach,
>   		  unsigned int scaler_user, int *scaler_id,
> diff --git a/drivers/gpu/drm/i915/display/skl_scaler.h b/drivers/gpu/drm/i915/display/skl_scaler.h
> index 355ea15260ca..7beee5ee0e89 100644
> --- a/drivers/gpu/drm/i915/display/skl_scaler.h
> +++ b/drivers/gpu/drm/i915/display/skl_scaler.h
> @@ -5,10 +5,16 @@
>   #ifndef INTEL_SCALER_H
>   #define INTEL_SCALER_H
>   
> +#include <linux/types.h>
> +
> +enum drm_mode_status;
> +struct drm_display_mode;
>   struct intel_atomic_state;
>   struct intel_crtc;
>   struct intel_crtc_state;
> +struct intel_display;
>   struct intel_dsb;
> +enum intel_output_format;
>   struct intel_plane;
>   struct intel_plane_state;
>   
> @@ -32,4 +38,10 @@ void skl_scaler_disable(const struct intel_crtc_state *old_crtc_state);
>   
>   void skl_scaler_get_config(struct intel_crtc_state *crtc_state);
>   
> +enum drm_mode_status
> +skl_scaler_mode_valid(struct intel_display *display,
> +		     const struct drm_display_mode *mode,
> +		     enum intel_output_format output_format,
> +		     int num_joined_pipes);
> +
>   #endif