[Intel-gfx] [PATCH 2/2] drm/i915: Configure SKL+ scaler initial phase correctly

Srinivas, Vidya vidya.srinivas at intel.com
Thu May 31 04:20:24 UTC 2018


Thank you.
Reviewed-By: Vidya Srinivas <vidya.srinivas at intel.com>

> -----Original Message-----
> From: Ville Syrjala [mailto:ville.syrjala at linux.intel.com]
> Sent: Tuesday, May 22, 2018 12:26 AM
> To: intel-gfx at lists.freedesktop.org
> Cc: Srinivas, Vidya <vidya.srinivas at intel.com>; Maarten Lankhorst
> <maarten.lankhorst at linux.intel.com>
> Subject: [PATCH 2/2] drm/i915: Configure SKL+ scaler initial phase correctly
> 
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Set up the SKL+ scaler initial phase registers correctly. Otherwise we start
> fetching the data from the center of the first pixel instead of the top-left
> corner, which obviously then leads to right/bottom edges replicating data
> excessively as the data runs out half a pixel too soon.
> 
> Cc: Vidya Srinivas <vidya.srinivas at intel.com>
> Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_reg.h      |  4 ++++
>  drivers/gpu/drm/i915/intel_display.c | 41
> ++++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/i915/intel_drv.h     |  1 +
>  drivers/gpu/drm/i915/intel_sprite.c  | 26 +++++++++++++++++++++--
>  4 files changed, 70 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_reg.h
> b/drivers/gpu/drm/i915/i915_reg.h index 196a0eb79272..094527403ede
> 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -6774,6 +6774,10 @@ enum {
>  #define _PS_VPHASE_1B       0x68988
>  #define _PS_VPHASE_2B       0x68A88
>  #define _PS_VPHASE_1C       0x69188
> +#define  PS_Y_PHASE(x)		((x) << 16)
> +#define  PS_UV_RGB_PHASE(x)	((x) << 0)
> +#define   PS_PHASE_MASK	(0x7fff << 1) /* u2.13 */
> +#define   PS_PHASE_TRIP	(1 << 0)
> 
>  #define _PS_HPHASE_1A       0x68194
>  #define _PS_HPHASE_2A       0x68294
> diff --git a/drivers/gpu/drm/i915/intel_display.c
> b/drivers/gpu/drm/i915/intel_display.c
> index 42c1f4a56556..07185644a88a 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -4729,6 +4729,39 @@ static void cpt_verify_modeset(struct
> drm_device *dev, int pipe)
>  	}
>  }
> 
> +/*
> + * The hardware phase 0.0 refers to the center of the pixel.
> + * We want to start from the top/left edge which is phase
> + * -0.5. That matches how the hardware calculates the scaling
> + * factors (from top-left of the first pixel to bottom-right
> + * of the last pixel, as opposed to the pixel centers).
> + *
> + * For 4:2:0 subsampled chroma planes we obviously have to
> + * adjust that so that the chroma sample position lands in
> + * the right spot.
> + *
> + * Note that for packed YCbCr 4:2:2 formats there is no way to
> + * control chroma siting. The hardware simply replicates the
> + * chroma samples for both of the luma samples, and thus we don't
> + * actually get the expected MPEG2 chroma siting convention :(
> + * The same behaviour is observed on pre-SKL platforms as well.
> + */
> +u16 skl_scaler_calc_phase(int sub, bool chroma_cosited) {
> +	int phase = -0x8000;
> +	u16 trip = 0;
> +
> +	if (chroma_cosited)
> +		phase += (sub - 1) * 0x8000 / sub;
> +
> +	if (phase < 0)
> +		phase = 0x10000 + phase;
> +	else
> +		trip = PS_PHASE_TRIP;
> +
> +	return ((phase >> 2) & PS_PHASE_MASK) | trip; }
> +
>  static int
>  skl_update_scaler(struct intel_crtc_state *crtc_state, bool force_detach,
>  		  unsigned int scaler_user, int *scaler_id, @@ -4928,14
> +4961,22 @@ static void skylake_pfit_enable(struct intel_crtc *crtc)
>  		&crtc->config->scaler_state;
> 
>  	if (crtc->config->pch_pfit.enabled) {
> +		u16 uv_rgb_hphase, uv_rgb_vphase;
>  		int id;
> 
>  		if (WARN_ON(crtc->config->scaler_state.scaler_id < 0))
>  			return;
> 
> +		uv_rgb_hphase = skl_scaler_calc_phase(1, false);
> +		uv_rgb_vphase = skl_scaler_calc_phase(1, false);
> +
>  		id = scaler_state->scaler_id;
>  		I915_WRITE(SKL_PS_CTRL(pipe, id), PS_SCALER_EN |
>  			PS_FILTER_MEDIUM | scaler_state-
> >scalers[id].mode);
> +		I915_WRITE_FW(SKL_PS_VPHASE(pipe, id),
> +			      PS_Y_PHASE(0) |
> PS_UV_RGB_PHASE(uv_rgb_vphase));
> +		I915_WRITE_FW(SKL_PS_HPHASE(pipe, id),
> +			      PS_Y_PHASE(0) |
> PS_UV_RGB_PHASE(uv_rgb_hphase));
>  		I915_WRITE(SKL_PS_WIN_POS(pipe, id), crtc->config-
> >pch_pfit.pos);
>  		I915_WRITE(SKL_PS_WIN_SZ(pipe, id), crtc->config-
> >pch_pfit.size);
>  	}
> diff --git a/drivers/gpu/drm/i915/intel_drv.h
> b/drivers/gpu/drm/i915/intel_drv.h
> index 42a59b7fd736..0f1dbfcf8538 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1621,6 +1621,7 @@ void intel_mode_from_pipe_config(struct
> drm_display_mode *mode,  void intel_crtc_arm_fifo_underrun(struct
> intel_crtc *crtc,
>  				  struct intel_crtc_state *crtc_state);
> 
> +u16 skl_scaler_calc_phase(int sub, bool chroma_center);
>  int skl_update_scaler_crtc(struct intel_crtc_state *crtc_state);  int
> skl_max_scale(struct intel_crtc *crtc, struct intel_crtc_state *crtc_state,
>  		  uint32_t pixel_format);
> diff --git a/drivers/gpu/drm/i915/intel_sprite.c
> b/drivers/gpu/drm/i915/intel_sprite.c
> index 214cc730642c..58522441253d 100644
> --- a/drivers/gpu/drm/i915/intel_sprite.c
> +++ b/drivers/gpu/drm/i915/intel_sprite.c
> @@ -284,13 +284,35 @@ skl_update_plane(struct intel_plane *plane,
>  	/* program plane scaler */
>  	if (plane_state->scaler_id >= 0) {
>  		int scaler_id = plane_state->scaler_id;
> -		const struct intel_scaler *scaler;
> +		const struct intel_scaler *scaler =
> +			&crtc_state->scaler_state.scalers[scaler_id];
> +		u16 y_hphase, uv_rgb_hphase;
> +		u16 y_vphase, uv_rgb_vphase;
> +
> +		/* TODO: handle sub-pixel coordinates */
> +		if (fb->format->format == DRM_FORMAT_NV12) {
> +			y_hphase = skl_scaler_calc_phase(1, false);
> +			y_vphase = skl_scaler_calc_phase(1, false);
> +
> +			/* MPEG2 chroma siting convention */
> +			uv_rgb_hphase = skl_scaler_calc_phase(2, true);
> +			uv_rgb_vphase = skl_scaler_calc_phase(2, false);
> +		} else {
> +			/* not used */
> +			y_hphase = 0;
> +			y_vphase = 0;
> 
> -		scaler = &crtc_state->scaler_state.scalers[scaler_id];
> +			uv_rgb_hphase = skl_scaler_calc_phase(1, false);
> +			uv_rgb_vphase = skl_scaler_calc_phase(1, false);
> +		}
> 
>  		I915_WRITE_FW(SKL_PS_CTRL(pipe, scaler_id),
>  			      PS_SCALER_EN | PS_PLANE_SEL(plane_id) |
> scaler->mode);
>  		I915_WRITE_FW(SKL_PS_PWR_GATE(pipe, scaler_id), 0);
> +		I915_WRITE_FW(SKL_PS_VPHASE(pipe, scaler_id),
> +			      PS_Y_PHASE(y_vphase) |
> PS_UV_RGB_PHASE(uv_rgb_vphase));
> +		I915_WRITE_FW(SKL_PS_HPHASE(pipe, scaler_id),
> +			      PS_Y_PHASE(y_hphase) |
> PS_UV_RGB_PHASE(uv_rgb_hphase));
>  		I915_WRITE_FW(SKL_PS_WIN_POS(pipe, scaler_id), (crtc_x
> << 16) | crtc_y);
>  		I915_WRITE_FW(SKL_PS_WIN_SZ(pipe, scaler_id),
>  			      ((crtc_w + 1) << 16)|(crtc_h + 1));
> --
> 2.16.1



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