[PATCH 2/2] drm/xe/stolen: ignore first page for FBC

[Matthew Auld <matthew.auld@intel.com>]

We have observed underruns on some platforms if the CFB offset is within
the first page of stolen. Just like i915 skip the first page.

v2 (Maarten)
  - Also align the start.

BSpec: 50214
Reported-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
---
 drivers/gpu/drm/xe/compat-i915-headers/i915_gem_stolen.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xe/compat-i915-headers/i915_gem_stolen.h b/drivers/gpu/drm/xe/compat-i915-headers/i915_gem_stolen.h
index b4ccc4231e7d..cb6c7598824b 100644
--- a/drivers/gpu/drm/xe/compat-i915-headers/i915_gem_stolen.h
+++ b/drivers/gpu/drm/xe/compat-i915-headers/i915_gem_stolen.h
@@ -19,8 +19,13 @@ static inline int i915_gem_stolen_insert_node_in_range(struct xe_device *xe,
 	int err;
 	u32 flags = XE_BO_FLAG_PINNED | XE_BO_FLAG_STOLEN;
 
-	if (align)
+	if (start < SZ_4K)
+		start = SZ_4K;
+
+	if (align) {
 		size = ALIGN(size, align);
+		start = ALIGN(start, align);
+	}
 
 	bo = xe_bo_create_locked_range(xe, xe_device_get_root_tile(xe),
 				       NULL, size, start, end,
-- 
2.44.0