On Wed, Nov 14, 2018 at 01:49:25PM +0200, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>
> To get the initial phase correct we need to account for the scale
> factor as well. I forgot this initially and was mostly looking at
> heavily upscaled content where the minor difference between -0.5
> and the proper initial phase was not readily apparent.
>
> And let's toss in a comment that tries to explain the formula
> a little bit.
>
> v2: The initial phase upper limit is 1.5, not 24.0!
>
> Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
> Fixes: 0a59952b24e2 ("drm/i915: Configure SKL+ scaler initial phase correctly")
> Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> Link: https://patchwork.freedesktop.org/patch/msgid/20181029181820.21956-1-ville.syrjala@xxxxxxxxxxxxxxx
> Tested-by: Juha-Pekka Heikkila <juhapekka.heikkila@xxxxxxxxx>
> Tested-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx> #irc
> Reviewed-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx> #irc
> (cherry picked from commit e7a278a329dd8aa2c70c564849f164cb5673689c)
> ---
> drivers/gpu/drm/i915/intel_display.c | 45 ++++++++++++++++++++++++++--
> drivers/gpu/drm/i915/intel_drv.h | 2 +-
> drivers/gpu/drm/i915/intel_sprite.c | 20 +++++++++----
> 3 files changed, 57 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 23d8008a93bb..636738c04eb2 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -4850,8 +4850,31 @@ static void cpt_verify_modeset(struct drm_device *dev, int pipe)
> * 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.
> + *
> + * Theory behind the formula (note that we ignore sub-pixel
> + * source coordinates):
> + * s = source sample position
> + * d = destination sample position
> + *
> + * Downscaling 4:1:
> + * -0.5
> + * | 0.0
> + * | | 1.5 (initial phase)
> + * | | |
> + * v v v
> + * | s | s | s | s |
> + * | d |
> + *
> + * Upscaling 1:4:
> + * -0.5
> + * | -0.375 (initial phase)
> + * | | 0.0
> + * | | |
> + * v v v
> + * | s |
> + * | d | d | d | d |
> */
> -u16 skl_scaler_calc_phase(int sub, bool chroma_cosited)
> +u16 skl_scaler_calc_phase(int sub, int scale, bool chroma_cosited)
> {
> int phase = -0x8000;
> u16 trip = 0;
> @@ -4859,6 +4882,15 @@ u16 skl_scaler_calc_phase(int sub, bool chroma_cosited)
> if (chroma_cosited)
> phase += (sub - 1) * 0x8000 / sub;
>
> + phase += scale / (2 * sub);
> +
> + /*
> + * Hardware initial phase limited to [-0.5:1.5].
> + * Since the max hardware scale factor is 3.0, we
> + * should never actually excdeed 1.0 here.
> + */
> + WARN_ON(phase < -0x8000 || phase > 0x18000);
> +
> if (phase < 0)
> phase = 0x10000 + phase;
> else
> @@ -5067,13 +5099,20 @@ static void skylake_pfit_enable(struct intel_crtc *crtc)
>
> if (crtc->config->pch_pfit.enabled) {
> u16 uv_rgb_hphase, uv_rgb_vphase;
> + int pfit_w, pfit_h, hscale, vscale;
> 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);
> + pfit_w = (crtc_state->pch_pfit.size >> 16) & 0xFFFF;
> + pfit_h = crtc_state->pch_pfit.size & 0xFFFF;
> +
> + hscale = (crtc_state->pipe_src_w << 16) / pfit_w;
> + vscale = (crtc_state->pipe_src_h << 16) / pfit_h;
Bah. This doesn't build. I'll fix and resend, and make doubly sure to
build test this time. Sorry for the noise.
> +
> + uv_rgb_hphase = skl_scaler_calc_phase(1, hscale, false);
> + uv_rgb_vphase = skl_scaler_calc_phase(1, vscale, false);
>
> id = scaler_state->scaler_id;
> I915_WRITE(SKL_PS_CTRL(pipe, id), PS_SCALER_EN |
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index f8dc84b2d2d3..8b298e5f012d 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1646,7 +1646,7 @@ 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);
> +u16 skl_scaler_calc_phase(int sub, int scale, bool chroma_center);
> int skl_update_scaler_crtc(struct intel_crtc_state *crtc_state);
> int skl_max_scale(const struct intel_crtc_state *crtc_state,
> u32 pixel_format);
> diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c
> index fa7eaace5f92..d3090a7537bb 100644
> --- a/drivers/gpu/drm/i915/intel_sprite.c
> +++ b/drivers/gpu/drm/i915/intel_sprite.c
> @@ -318,22 +318,30 @@ skl_program_scaler(struct intel_plane *plane,
> uint32_t crtc_h = drm_rect_height(&plane_state->base.dst);
> u16 y_hphase, uv_rgb_hphase;
> u16 y_vphase, uv_rgb_vphase;
> + int hscale, vscale;
> +
> + hscale = drm_rect_calc_hscale(&plane_state->base.src,
> + &plane_state->base.dst,
> + 0, INT_MAX);
> + vscale = drm_rect_calc_vscale(&plane_state->base.src,
> + &plane_state->base.dst,
> + 0, INT_MAX);
>
> /* TODO: handle sub-pixel coordinates */
> if (plane_state->base.fb->format->format == DRM_FORMAT_NV12) {
> - y_hphase = skl_scaler_calc_phase(1, false);
> - y_vphase = skl_scaler_calc_phase(1, false);
> + y_hphase = skl_scaler_calc_phase(1, hscale, false);
> + y_vphase = skl_scaler_calc_phase(1, vscale, false);
>
> /* MPEG2 chroma siting convention */
> - uv_rgb_hphase = skl_scaler_calc_phase(2, true);
> - uv_rgb_vphase = skl_scaler_calc_phase(2, false);
> + uv_rgb_hphase = skl_scaler_calc_phase(2, hscale, true);
> + uv_rgb_vphase = skl_scaler_calc_phase(2, vscale, false);
> } else {
> /* not used */
> y_hphase = 0;
> y_vphase = 0;
>
> - uv_rgb_hphase = skl_scaler_calc_phase(1, false);
> - uv_rgb_vphase = skl_scaler_calc_phase(1, false);
> + uv_rgb_hphase = skl_scaler_calc_phase(1, hscale, false);
> + uv_rgb_vphase = skl_scaler_calc_phase(1, vscale, false);
> }
>
> I915_WRITE_FW(SKL_PS_CTRL(pipe, scaler_id),
> --
> 2.18.1
--
Ville Syrjälä
Intel
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