[PATCH 4/9] drm/i915: Avoid div-by-zero when computing aux_stride w/o an aux plane

[ville.syrjala at linux.intel.com]

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

To make life easier let's allow skl_plane_stride() to be called for the
AUX surface even when there is no AUX surface. Avoids special cases in
the callers.

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 4d514ca1da88..bc398743e941 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -3261,7 +3261,12 @@ static void skl_detach_scalers(struct intel_crtc *intel_crtc)
 u32 skl_plane_stride(const struct drm_framebuffer *fb, int plane,
 		     unsigned int rotation)
 {
-	u32 stride = intel_fb_pitch(fb, plane, rotation);
+	u32 stride;
+
+	if (plane >= fb->format->num_planes)
+		return 0;
+
+	stride = intel_fb_pitch(fb, plane, rotation);
 
 	/*
 	 * The stride is either expressed as a multiple of 64 bytes chunks for
-- 
2.10.2