[PATCH v1 5/9] drm/i915/scaler: check CASF before allocation's loop

["Michał Grzelak" <michal.grzelak@intel.com>]

intel_allocate_scaler() checks if casf_scaler is true and either
allocates second scaler or fails if it was already allocated. Mimic this
outside of the loop. Also fail the allocation if number of scalers is
less than 2.

Cc: Nemesa Garg <nemesa.garg@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Michał Grzelak <michal.grzelak@intel.com>
---
 drivers/gpu/drm/i915/display/skl_scaler.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/skl_scaler.c b/drivers/gpu/drm/i915/display/skl_scaler.c
index 59a5a3cd3e6a..29e4047c3f99 100644
--- a/drivers/gpu/drm/i915/display/skl_scaler.c
+++ b/drivers/gpu/drm/i915/display/skl_scaler.c
@@ -339,16 +339,24 @@ static int intel_allocate_scaler(struct intel_crtc_scaler_state *scaler_state,
 	struct intel_display *display = to_intel_display(crtc);
 	int scaler_id;
 
-	if (casf_scaler && !HAS_CASF(display))
-		return -1;
+	if (casf_scaler) {
+		if (!HAS_CASF(display))
+			return -1;
+
+		if (crtc->num_scalers < 2)
+			return -1;
+
+		if (scaler_state->scalers[1].in_use)
+			return -1;
+
+		scaler_state->scalers[1].in_use = true;
+		return 1;
+	}
 
 	for (scaler_id = 0; scaler_id < crtc->num_scalers; scaler_id++) {
 		if (scaler_state->scalers[scaler_id].in_use)
 			continue;
 
-		if (casf_scaler && scaler_id != 1)
-			continue;
-
 		scaler_state->scalers[scaler_id].in_use = true;
 
 		return scaler_id;
-- 
2.45.2