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drm/i915: Fix plane relative_data_rate calculation

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We are currently computing the relative data rates as
src_size * scale_factor where scale_factor is src_size / dst_size.
Thus relative data rate is src_size * src_size / dst_size,
which is just utter nonsense. What we really seem to want is
just a reasonable estimate on how much data will be fetched
which is just src_size. So let's do that instead.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220118092354.11631-4-ville.syrjala@linux.intel.com
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
This commit is contained in:
Ville Syrjälä 2022-01-18 11:23:42 +02:00
parent 8a84e7a176
commit 759d4fff3d
1 changed files with 2 additions and 61 deletions
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63
drivers/gpu/drm/i915/intel_pm.c
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@ -4356,55 +4356,6 @@ void skl_pipe_ddb_get_hw_state(struct intel_crtc *crtc,
intel_display_power_put(dev_priv, power_domain, wakeref);
}
/*
* Determines the downscale amount of a plane for the purposes of watermark calculations.
* The bspec defines downscale amount as:
*
* """
* Horizontal down scale amount = maximum[1, Horizontal source size /
* Horizontal destination size]
* Vertical down scale amount = maximum[1, Vertical source size /
* Vertical destination size]
* Total down scale amount = Horizontal down scale amount *
* Vertical down scale amount
* """
*
* Return value is provided in 16.16 fixed point form to retain fractional part.
* Caller should take care of dividing & rounding off the value.
*/
static uint_fixed_16_16_t
skl_plane_downscale_amount(const struct intel_crtc_state *crtc_state,
const struct intel_plane_state *plane_state)
{
struct drm_i915_private *dev_priv = to_i915(crtc_state->uapi.crtc->dev);
u32 src_w, src_h, dst_w, dst_h;
uint_fixed_16_16_t fp_w_ratio, fp_h_ratio;
uint_fixed_16_16_t downscale_h, downscale_w;
if (drm_WARN_ON(&dev_priv->drm,
!intel_wm_plane_visible(crtc_state, plane_state)))
return u32_to_fixed16(0);
/*
* Src coordinates are already rotated by 270 degrees for
* the 90/270 degree plane rotation cases (to match the
* GTT mapping), hence no need to account for rotation here.
*
* n.b., src is 16.16 fixed point, dst is whole integer.
*/
src_w = drm_rect_width(&plane_state->uapi.src) >> 16;
src_h = drm_rect_height(&plane_state->uapi.src) >> 16;
dst_w = drm_rect_width(&plane_state->uapi.dst);
dst_h = drm_rect_height(&plane_state->uapi.dst);
fp_w_ratio = div_fixed16(src_w, dst_w);
fp_h_ratio = div_fixed16(src_h, dst_h);
downscale_w = max_fixed16(fp_w_ratio, u32_to_fixed16(1));
downscale_h = max_fixed16(fp_h_ratio, u32_to_fixed16(1));
return mul_fixed16(downscale_w, downscale_h);
}
struct dbuf_slice_conf_entry {
u8 active_pipes;
u8 dbuf_mask[I915_MAX_PIPES];
@ -4960,10 +4911,7 @@ skl_plane_relative_data_rate(const struct intel_crtc_state *crtc_state,
{
struct intel_plane *plane = to_intel_plane(plane_state->uapi.plane);
const struct drm_framebuffer *fb = plane_state->hw.fb;
u32 data_rate;
u32 width = 0, height = 0;
uint_fixed_16_16_t down_scale_amount;
u64 rate;
int width, height;
if (!plane_state->uapi.visible)
return 0;
@ -4997,14 +4945,7 @@ skl_plane_relative_data_rate(const struct intel_crtc_state *crtc_state,
height /= 2;
}
data_rate = width * height;
down_scale_amount = skl_plane_downscale_amount(crtc_state, plane_state);
rate = mul_round_up_u32_fixed16(data_rate, down_scale_amount);
rate *= fb->format->cpp[color_plane];
return rate;
return width * height * fb->format->cpp[color_plane];
}
static u64