[PATCH 10/10] drm/i915: Reject BIOS FB rotation in common code

Ville Syrjala
2026-04-10T15:05:39Z

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

Reject 90/270 degree rotated BIOS framebuffers in common
code. Currently skl_get_initial_plane_config() already rejects
these, but we may want to implement the missing parts there
so that skl_get_initial_plane_config() could be reused for
general plane state verification purposes.

90/270 degree rotated framebuffers require two completely
separate GGTT mappings (0 degree for the CPU, 270 degree
for the display engine), and the rest of the BIOS FB
takeover code is not prepared for that.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
drivers/gpu/drm/i915/display/intel_initial_plane.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_initial_plane.c b/drivers/gpu/drm/i915/display/intel_initial_plane.c
index e3d1b2d1669c..0e5cd45f01cc 100644
--- a/drivers/gpu/drm/i915/display/intel_initial_plane.c
+++ b/drivers/gpu/drm/i915/display/intel_initial_plane.c
@@ -3,6 +3,7 @@

#include <linux/iopoll.h>

+#include <drm/drm_blend.h>
#include <drm/drm_print.h>
#include <drm/intel/display_parent_interface.h>

@@ -101,6 +102,15 @@ intel_alloc_initial_plane_obj(struct intel_display *display,
return NULL;
}

+ /*
+ * Would need to preserve the 270 degree rotated
+ * GGTT mapping used by the display hardware.
+ */
+ if (drm_rotation_90_or_270(plane_config->rotation)) {
+ drm_dbg_kms(display->drm, "90/270 degree rotation not supported for initial FB\n");
+ return NULL;
+ }
+
return display->parent->initial_plane->alloc_obj(display->drm, plane_config);
}

--
2.52.0