[Intel-gfx] [PATCH v4 05/11] drm/i915: Disallow plane scaling with specific pixel formats

[Ville Syrjala]

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

Plane scaling is not supported with specific pixel formats. Disallow
plane scaling when such a format is used. Currently the only such
pixel format we expose is C8, but in case we add more in the future
let's make it easy to deal with them.

v2: Redo due to plane_check() refactoring

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com> #v1
---
 drivers/gpu/drm/i915/intel_sprite.c | 47 ++++++++++++++++++++++---------------
 1 file changed, 28 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c
index 3ee025411d61..4b7f62ac441d 100644
--- a/drivers/gpu/drm/i915/intel_sprite.c
+++ b/drivers/gpu/drm/i915/intel_sprite.c
@@ -1070,6 +1070,19 @@ g4x_plane_get_hw_state(struct intel_plane *plane,
 	return ret;
 }
 
+static bool intel_fb_scalable(const struct drm_framebuffer *fb)
+{
+	if (!fb)
+		return false;
+
+	switch (fb->format->format) {
+	case DRM_FORMAT_C8:
+		return false;
+	default:
+		return true;
+	}
+}
+
 static int
 g4x_sprite_check_scaling(struct intel_crtc_state *crtc_state,
 			 struct intel_plane_state *plane_state)
@@ -1137,18 +1150,18 @@ g4x_sprite_check(struct intel_crtc_state *crtc_state,
 {
 	struct intel_plane *plane = to_intel_plane(plane_state->base.plane);
 	struct drm_i915_private *dev_priv = to_i915(plane->base.dev);
-	int max_scale, min_scale;
+	int min_scale = DRM_PLANE_HELPER_NO_SCALING;
+	int max_scale = DRM_PLANE_HELPER_NO_SCALING;
 	int ret;
 
-	if (INTEL_GEN(dev_priv) < 7) {
-		min_scale = 1;
-		max_scale = 16 << 16;
-	} else if (IS_IVYBRIDGE(dev_priv)) {
-		min_scale = 1;
-		max_scale = 2 << 16;
-	} else {
-		min_scale = DRM_PLANE_HELPER_NO_SCALING;
-		max_scale = DRM_PLANE_HELPER_NO_SCALING;
+	if (intel_fb_scalable(plane_state->base.fb)) {
+		if (INTEL_GEN(dev_priv) < 7) {
+			min_scale = 1;
+			max_scale = 16 << 16;
+		} else if (IS_IVYBRIDGE(dev_priv)) {
+			min_scale = 1;
+			max_scale = 2 << 16;
+		}
 	}
 
 	ret = drm_atomic_helper_check_plane_state(&plane_state->base,
@@ -1334,7 +1347,9 @@ int skl_plane_check(struct intel_crtc_state *crtc_state,
 {
 	struct intel_plane *plane = to_intel_plane(plane_state->base.plane);
 	struct drm_i915_private *dev_priv = to_i915(plane->base.dev);
-	int max_scale, min_scale;
+	const struct drm_framebuffer *fb = plane_state->base.fb;
+	int min_scale = DRM_PLANE_HELPER_NO_SCALING;
+	int max_scale = DRM_PLANE_HELPER_NO_SCALING;
 	int ret;
 
 	ret = skl_plane_check_fb(crtc_state, plane_state);
@@ -1342,15 +1357,9 @@ int skl_plane_check(struct intel_crtc_state *crtc_state,
 		return ret;
 
 	/* use scaler when colorkey is not required */
-	if (!plane_state->ckey.flags) {
-		const struct drm_framebuffer *fb = plane_state->base.fb;
-
+	if (!plane_state->ckey.flags && intel_fb_scalable(fb)) {
 		min_scale = 1;
-		max_scale = skl_max_scale(crtc_state,
-					  fb ? fb->format->format : 0);
-	} else {
-		min_scale = DRM_PLANE_HELPER_NO_SCALING;
-		max_scale = DRM_PLANE_HELPER_NO_SCALING;
+		max_scale = skl_max_scale(crtc_state, fb->format->format);
 	}
 
 	ret = drm_atomic_helper_check_plane_state(&plane_state->base,
-- 
2.16.4