Re: [Intel-gfx] [PATCH v3 1/2] drm/i915/mtl: limit second scaler vertical scaling in ver >= 14

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Nov 22, 2022 at 12:23:43PM +0200, Luca Coelho wrote:
> In newer hardware versions (i.e. display version >= 14), the second
> scaler doesn't support vertical scaling.
> 
> The current implementation of the scaling limits is simplified and
> only occurs when the planes are created, so we don't know which scaler
> is being used.
> 
> In order to handle separate scaling limits for horizontal and vertical
> scaling, and different limits per scaler, split the checks in two
> phases.  We first do a simple check during plane creation and use the
> best-case scenario (because we don't know the scaler that may be used
> at a later point) and then do a more specific check when the scalers
> are actually being set up.
> 
> Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
> ---
> 
> In v2:
>    * fix DRM_PLANE_NO_SCALING renamed macros;
> 
> In v3:
>    * No changes.
> 
> drivers/gpu/drm/i915/display/i9xx_plane.c     |  4 +-
>  drivers/gpu/drm/i915/display/intel_atomic.c   | 47 +++++++++++++++++++
>  .../gpu/drm/i915/display/intel_atomic_plane.c | 39 +++++++++++++--
>  .../gpu/drm/i915/display/intel_atomic_plane.h |  2 +-
>  drivers/gpu/drm/i915/display/intel_cursor.c   |  4 +-
>  drivers/gpu/drm/i915/display/intel_sprite.c   | 19 ++------
>  .../drm/i915/display/skl_universal_plane.c    | 26 ++--------
>  7 files changed, 91 insertions(+), 50 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/i9xx_plane.c b/drivers/gpu/drm/i915/display/i9xx_plane.c
> index ecaeb7dc196b..390e96f0692b 100644
> --- a/drivers/gpu/drm/i915/display/i9xx_plane.c
> +++ b/drivers/gpu/drm/i915/display/i9xx_plane.c
> @@ -326,9 +326,7 @@ i9xx_plane_check(struct intel_crtc_state *crtc_state,
>  	if (ret)
>  		return ret;
>  
> -	ret = intel_atomic_plane_check_clipping(plane_state, crtc_state,
> -						DRM_PLANE_NO_SCALING,
> -						DRM_PLANE_NO_SCALING,
> +	ret = intel_atomic_plane_check_clipping(plane_state, crtc_state, false,
>  						i9xx_plane_has_windowing(plane));
>  	if (ret)
>  		return ret;
> diff --git a/drivers/gpu/drm/i915/display/intel_atomic.c b/drivers/gpu/drm/i915/display/intel_atomic.c
> index 6621aa245caf..43b1c7a227f8 100644
> --- a/drivers/gpu/drm/i915/display/intel_atomic.c
> +++ b/drivers/gpu/drm/i915/display/intel_atomic.c
> @@ -38,6 +38,7 @@
>  #include "intel_atomic.h"
>  #include "intel_cdclk.h"
>  #include "intel_display_types.h"
> +#include "intel_fb.h"
>  #include "intel_global_state.h"
>  #include "intel_hdcp.h"
>  #include "intel_psr.h"
> @@ -375,6 +376,52 @@ static void intel_atomic_setup_scaler(struct intel_crtc_scaler_state *scaler_sta
>  		mode = SKL_PS_SCALER_MODE_DYN;
>  	}
>  
> +	if (plane_state && plane_state->hw.fb) {
> +		const struct drm_framebuffer *fb = plane_state->hw.fb;
> +		struct drm_rect *src = &plane_state->uapi.src;
> +		struct drm_rect *dst = &plane_state->uapi.dst;

We want the scale factor checks for the pfit use case too. So this
stuff shouldn't be so tied into planes. I guess we could go with
a FIXME initially.

> +		int hscale, vscale, max_vscale, max_hscale;
> +
> +		if (DISPLAY_VER(dev_priv) >= 14) {
> +			/*
> +			 * On versions 14 and up, only the first
> +			 * scaler supports a vertical scaling factor
> +			 * of more than 1.0, while a horizontal
> +			 * scaling factor of 3.0 is supported.
> +			 */
> +			max_hscale = 0x30000 - 1;
> +			if (*scaler_id == 0)
> +				max_vscale = 0x30000 - 1;
> +			else
> +				max_vscale = 0x10000;

We still have the chicken vs. egg problem here that we'd need to
consider the scale factors already when selecting the scaler.
But that could be another FIXME.

> +
> +		} else if (DISPLAY_VER(dev_priv) >= 10 ||
> +			   !intel_format_info_is_yuv_semiplanar(fb->format, fb->modifier)) {
> +			max_hscale = 0x30000 - 1;
> +			max_vscale = 0x30000 - 1;
> +		} else {
> +			max_hscale = 0x20000 - 1;
> +			max_vscale = 0x20000 - 1;
> +		}

Pre-glk hq scaler case not handled.

> +
> +		/* Check if required scaling is within limits */
> +		hscale = drm_rect_calc_hscale(src, dst, 1, max_hscale);
> +		vscale = drm_rect_calc_vscale(src, dst, 1, max_vscale);
> +
> +		if (hscale < 0 || vscale < 0) {
> +			drm_dbg_kms(&dev_priv->drm,
> +				    "Scaler %d doesn't support required plane scaling\n",
> +				    *scaler_id);
> +			drm_rect_debug_print("src: ", src, true);
> +			drm_rect_debug_print("dst: ", dst, false);
> +
> +			scaler_state->scalers[*scaler_id].in_use = 0;
> +			*scaler_id = -1;
> +
> +			return;

This would have to return an error rather than pretending that
everything is fine.

> +		}
> +	}
> +
>  	drm_dbg_kms(&dev_priv->drm, "Attached scaler id %u.%u to %s:%d\n",
>  		    intel_crtc->pipe, *scaler_id, name, idx);
>  	scaler_state->scalers[*scaler_id].mode = mode;
> diff --git a/drivers/gpu/drm/i915/display/intel_atomic_plane.c b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> index 10e1fc9d0698..9100f328df60 100644
> --- a/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> +++ b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> @@ -887,7 +887,7 @@ void intel_crtc_planes_update_arm(struct intel_atomic_state *state,
>  
>  int intel_atomic_plane_check_clipping(struct intel_plane_state *plane_state,
>  				      struct intel_crtc_state *crtc_state,
> -				      int min_scale, int max_scale,
> +				      bool allow_scaling,
>  				      bool can_position)
>  {
>  	struct drm_i915_private *i915 = to_i915(plane_state->uapi.plane->dev);
> @@ -897,19 +897,50 @@ int intel_atomic_plane_check_clipping(struct intel_plane_state *plane_state,
>  	const struct drm_rect *clip = &crtc_state->pipe_src;
>  	unsigned int rotation = plane_state->hw.rotation;
>  	int hscale, vscale;
> +	int max_hscale, min_hscale, max_vscale, min_vscale;
>  
>  	if (!fb) {
>  		plane_state->uapi.visible = false;
>  		return 0;
>  	}
>  
> +	/*
> +	 * At this point we don't really know the HW limitations, so
> +	 * we just sanitize the values against the maximum supported
> +	 * scaling.
> +	 */
> +	if (allow_scaling) {
> +		min_vscale = 1;
> +		min_hscale = 1;
> +
> +		if (DISPLAY_VER(i915) < 10 ||
> +		    intel_format_info_is_yuv_semiplanar(fb->format,
> +							fb->modifier)) {
> +			max_vscale = 0x20000 - 1;
> +			max_hscale = 0x20000 - 1;
> +		} else {
> +			max_vscale = 0x30000 - 1;
> +			max_hscale = 0x30000 - 1;
> +		}
> +	} else {
> +		min_hscale = DRM_PLANE_NO_SCALING;
> +		max_hscale = DRM_PLANE_NO_SCALING;
> +		min_vscale = DRM_PLANE_NO_SCALING;
> +		max_vscale = DRM_PLANE_NO_SCALING;
> +	}

I still don't see the point in moving this hw specific knowledge
from the more hw specific files into the hw agnostic file.

> +
>  	drm_rect_rotate(src, fb->width << 16, fb->height << 16, rotation);
>  
>  	/* Check scaling */
> -	hscale = drm_rect_calc_hscale(src, dst, min_scale, max_scale);
> -	vscale = drm_rect_calc_vscale(src, dst, min_scale, max_scale);
> +	hscale = drm_rect_calc_hscale(src, dst, min_hscale, max_hscale);
> +	vscale = drm_rect_calc_vscale(src, dst, min_vscale, max_vscale);
>  	if (hscale < 0 || vscale < 0) {
> -		drm_dbg_kms(&i915->drm, "Invalid scaling of plane\n");
> +		drm_dbg_kms(&i915->drm,
> +			    "Invalid scaling of plane: hscale 0x%x vscale 0x%x\n",
> +			    hscale, vscale);
> +		drm_dbg_kms(&i915->drm,
> +			    "min_hscale 0x%0x max_hscale 0x%0x min_vscale 0x%0x max_vscale 0x%0x\n",
> +			    min_hscale, max_hscale, min_vscale, max_vscale);
>  		drm_rect_debug_print("src: ", src, true);
>  		drm_rect_debug_print("dst: ", dst, false);
>  		return -ERANGE;
> diff --git a/drivers/gpu/drm/i915/display/intel_atomic_plane.h b/drivers/gpu/drm/i915/display/intel_atomic_plane.h
> index 74b6d3b169a7..441ef8165212 100644
> --- a/drivers/gpu/drm/i915/display/intel_atomic_plane.h
> +++ b/drivers/gpu/drm/i915/display/intel_atomic_plane.h
> @@ -60,7 +60,7 @@ int intel_plane_calc_min_cdclk(struct intel_atomic_state *state,
>  			       bool *need_cdclk_calc);
>  int intel_atomic_plane_check_clipping(struct intel_plane_state *plane_state,
>  				      struct intel_crtc_state *crtc_state,
> -				      int min_scale, int max_scale,
> +				      bool check_scaling,
>  				      bool can_position);
>  void intel_plane_set_invisible(struct intel_crtc_state *crtc_state,
>  			       struct intel_plane_state *plane_state);
> diff --git a/drivers/gpu/drm/i915/display/intel_cursor.c b/drivers/gpu/drm/i915/display/intel_cursor.c
> index d190fa0d393b..741ec74f54f6 100644
> --- a/drivers/gpu/drm/i915/display/intel_cursor.c
> +++ b/drivers/gpu/drm/i915/display/intel_cursor.c
> @@ -144,9 +144,7 @@ static int intel_check_cursor(struct intel_crtc_state *crtc_state,
>  	}
>  
>  	ret = intel_atomic_plane_check_clipping(plane_state, crtc_state,
> -						DRM_PLANE_NO_SCALING,
> -						DRM_PLANE_NO_SCALING,
> -						true);
> +						false, true);
>  	if (ret)
>  		return ret;
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_sprite.c b/drivers/gpu/drm/i915/display/intel_sprite.c
> index e6b4d24b9cd0..9ad1173a0551 100644
> --- a/drivers/gpu/drm/i915/display/intel_sprite.c
> +++ b/drivers/gpu/drm/i915/display/intel_sprite.c
> @@ -1355,22 +1355,11 @@ g4x_sprite_check(struct intel_crtc_state *crtc_state,
>  {
>  	struct intel_plane *plane = to_intel_plane(plane_state->uapi.plane);
>  	struct drm_i915_private *dev_priv = to_i915(plane->base.dev);
> -	int min_scale = DRM_PLANE_NO_SCALING;
> -	int max_scale = DRM_PLANE_NO_SCALING;
>  	int ret;
>  
> -	if (g4x_fb_scalable(plane_state->hw.fb)) {
> -		if (DISPLAY_VER(dev_priv) < 7) {
> -			min_scale = 1;
> -			max_scale = 16 << 16;
> -		} else if (IS_IVYBRIDGE(dev_priv)) {
> -			min_scale = 1;
> -			max_scale = 2 << 16;
> -		}
> -	}

So what happened to these limits?

> -
>  	ret = intel_atomic_plane_check_clipping(plane_state, crtc_state,
> -						min_scale, max_scale, true);
> +						g4x_fb_scalable(plane_state->hw.fb),
> +						true);
>  	if (ret)
>  		return ret;
>  
> @@ -1426,9 +1415,7 @@ vlv_sprite_check(struct intel_crtc_state *crtc_state,
>  		return ret;
>  
>  	ret = intel_atomic_plane_check_clipping(plane_state, crtc_state,
> -						DRM_PLANE_NO_SCALING,
> -						DRM_PLANE_NO_SCALING,
> -						true);
> +						false, true);
>  	if (ret)
>  		return ret;
>  
> diff --git a/drivers/gpu/drm/i915/display/skl_universal_plane.c b/drivers/gpu/drm/i915/display/skl_universal_plane.c
> index 76490cc59d8f..e2ae6624378f 100644
> --- a/drivers/gpu/drm/i915/display/skl_universal_plane.c
> +++ b/drivers/gpu/drm/i915/display/skl_universal_plane.c
> @@ -1463,22 +1463,6 @@ static int skl_plane_check_nv12_rotation(const struct intel_plane_state *plane_s
>  	return 0;
>  }
>  
> -static int skl_plane_max_scale(struct drm_i915_private *dev_priv,
> -			       const struct drm_framebuffer *fb)
> -{
> -	/*
> -	 * We don't yet know the final source width nor
> -	 * whether we can use the HQ scaler mode. Assume
> -	 * the best case.
> -	 * FIXME need to properly check this later.
> -	 */

Doesn't look like that FIXME has been dealt with as far
as the hq scaler is concerned.

> -	if (DISPLAY_VER(dev_priv) >= 10 ||
> -	    !intel_format_info_is_yuv_semiplanar(fb->format, fb->modifier))
> -		return 0x30000 - 1;
> -	else
> -		return 0x20000 - 1;
> -}
> -
>  static int intel_plane_min_width(struct intel_plane *plane,
>  				 const struct drm_framebuffer *fb,
>  				 int color_plane,
> @@ -1862,8 +1846,7 @@ static int skl_plane_check(struct intel_crtc_state *crtc_state,
>  	struct intel_plane *plane = to_intel_plane(plane_state->uapi.plane);
>  	struct drm_i915_private *dev_priv = to_i915(plane->base.dev);
>  	const struct drm_framebuffer *fb = plane_state->hw.fb;
> -	int min_scale = DRM_PLANE_NO_SCALING;
> -	int max_scale = DRM_PLANE_NO_SCALING;
> +	bool allow_scaling;
>  	int ret;
>  
>  	ret = skl_plane_check_fb(crtc_state, plane_state);
> @@ -1871,13 +1854,10 @@ static int skl_plane_check(struct intel_crtc_state *crtc_state,
>  		return ret;
>  
>  	/* use scaler when colorkey is not required */
> -	if (!plane_state->ckey.flags && skl_fb_scalable(fb)) {
> -		min_scale = 1;
> -		max_scale = skl_plane_max_scale(dev_priv, fb);
> -	}
> +	allow_scaling = !plane_state->ckey.flags && skl_fb_scalable(fb);
>  
>  	ret = intel_atomic_plane_check_clipping(plane_state, crtc_state,
> -						min_scale, max_scale, true);
> +						allow_scaling, true);
>  	if (ret)
>  		return ret;
>  
> -- 
> 2.38.1

-- 
Ville Syrjälä
Intel