[PATCH 08/11] drm/i915: Extract intel_plane_needs_fence()

Ville Syrjala
2026-04-16T17:45:32Z

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

Extract the naked DISPLA_VER<4 checks into a descriptive little
helper (intel_plane_needs_fence()).

And while at it document the reason why the check is what it is.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
drivers/gpu/drm/i915/display/intel_fb.c | 2 +-
drivers/gpu/drm/i915/display/intel_plane.c | 9 +++++++++
drivers/gpu/drm/i915/display/intel_plane.h | 1 +
drivers/gpu/drm/i915/i915_fb_pin.c | 2 +-
4 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_fb.c b/drivers/gpu/drm/i915/display/intel_fb.c
index cbeb39ebdb73..1c0859d5f829 100644
--- a/drivers/gpu/drm/i915/display/intel_fb.c
+++ b/drivers/gpu/drm/i915/display/intel_fb.c
@@ -1287,7 +1287,7 @@ bool intel_plane_uses_fence(const struct intel_plane_state *plane_state)
struct intel_display *display = to_intel_display(plane_state);
struct intel_plane *plane = to_intel_plane(plane_state->uapi.plane);

- return DISPLAY_VER(display) < 4 ||
+ return intel_plane_needs_fence(display) ||
(plane->fbc && !plane_state->no_fbc_reason &&
i915_gtt_view_is_normal(&plane_state->view.gtt));
}
diff --git a/drivers/gpu/drm/i915/display/intel_plane.c b/drivers/gpu/drm/i915/display/intel_plane.c
index f41f4c2ac320..c2b58d3b9c23 100644
--- a/drivers/gpu/drm/i915/display/intel_plane.c
+++ b/drivers/gpu/drm/i915/display/intel_plane.c
@@ -192,6 +192,15 @@ bool intel_plane_needs_physical(struct intel_plane *plane)
DISPLAY_INFO(display)->cursor_needs_physical;
}

+bool intel_plane_needs_fence(struct intel_display *display)
+{
+ /*
+ * pre-i965 planes use the fence for tiled scanout.
+ * i965+ planes have their own tiled scanout control bit.
+ */
+ return DISPLAY_VER(display) < 4;
+}
+
bool intel_plane_can_async_flip(struct intel_plane *plane,
const struct drm_format_info *info,
u64 modifier)
diff --git a/drivers/gpu/drm/i915/display/intel_plane.h b/drivers/gpu/drm/i915/display/intel_plane.h
index 7fa7fbbb58dc..7b5456f56f42 100644
--- a/drivers/gpu/drm/i915/display/intel_plane.h
+++ b/drivers/gpu/drm/i915/display/intel_plane.h
@@ -82,6 +82,7 @@ void intel_plane_set_invisible(struct intel_crtc_state *crtc_state,
void intel_plane_helper_add(struct intel_plane *plane);
bool intel_plane_needs_low_address(struct intel_display *display);
bool intel_plane_needs_physical(struct intel_plane *plane);
+bool intel_plane_needs_fence(struct intel_display *display);
void intel_plane_init_cursor_vblank_work(struct intel_plane_state *old_plane_state,
struct intel_plane_state *new_plane_state);
int intel_plane_add_affected(struct intel_atomic_state *state,
diff --git a/drivers/gpu/drm/i915/i915_fb_pin.c b/drivers/gpu/drm/i915/i915_fb_pin.c
index bfe9a5342e13..a8ed888183cb 100644
--- a/drivers/gpu/drm/i915/i915_fb_pin.c
+++ b/drivers/gpu/drm/i915/i915_fb_pin.c
@@ -188,7 +188,7 @@ intel_fb_pin_to_ggtt(const struct drm_framebuffer *fb,
* mode that matches the user configuration.
*/
ret = i915_vma_pin_fence(vma);
- if (ret != 0 && DISPLAY_VER(display) < 4) {
+ if (ret != 0 && intel_plane_needs_fence(display)) {
i915_vma_unpin(vma);
goto err_unpin;
}
--
2.52.0