drm/radeon/kms: detect sideport memory on IGP chips

This detects if the sideport memory is enabled and
if it is VRAM is evicted on suspend/resume.

This should fix s/r issues on some IGPs.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c
index d9ffe1f..4e636de 100644
--- a/drivers/gpu/drm/radeon/radeon_object.c
+++ b/drivers/gpu/drm/radeon/radeon_object.c
@@ -221,8 +221,9 @@
 int radeon_bo_evict_vram(struct radeon_device *rdev)
 {
 	if (rdev->flags & RADEON_IS_IGP) {
-		/* Useless to evict on IGP chips */
-		return 0;
+		if (rdev->mc.igp_sideport_enabled == false)
+			/* Useless to evict on IGP chips */
+			return 0;
 	}
 	return ttm_bo_evict_mm(&rdev->mman.bdev, TTM_PL_VRAM);
 }