[Intel-gfx] [PATCH 1/2] drm/i915: Fix g4x+ sprite dotclock limit for upscaling

[Ville Syrjala]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

Even if we're not doing downscaling we should account for
some of the extra dotclock limitations for g4x+ sprites. In
particular we must never exceed the 90% rule, and with RGB
that limits actually drops to 80%.

So instead of bailing out when upscaling let's clamp the
scaling factor appropriately and go through the rest of
calculation normally. By luck we already did the full
calculations for the 1:1 case.

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_sprite.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_sprite.c b/drivers/gpu/drm/i915/display/intel_sprite.c
index 7abeefe8dce5..6e2e22d9bbaa 100644
--- a/drivers/gpu/drm/i915/display/intel_sprite.c
+++ b/drivers/gpu/drm/i915/display/intel_sprite.c
@@ -1611,8 +1611,7 @@ static int g4x_sprite_min_cdclk(const struct intel_crtc_state *crtc_state,
 	hscale = drm_rect_calc_hscale(&plane_state->uapi.src,
 				      &plane_state->uapi.dst,
 				      0, INT_MAX);
-	if (hscale < 0x10000)
-		return pixel_rate;
+	hscale = max(hscale, 0x10000u);
 
 	/* Decimation steps at 2x,4x,8x,16x */
 	decimate = ilog2(hscale >> 16);
-- 
2.24.1