[v2,1/2] drm/i915/fbc: keep FBC disabled if selective update is on in xe2lpd

Commit Message

Vinod Govindapillai March 19, 2025, 1:51 p.m. UTC

FBC was disabled in case PSR2 selective update in display 12 to
14 as part of a wa. From xe2lpd onwards there is a logic to be
implemented to decide between FBC and selective update. Until
that logic is implemented keep FBC disabled in case selective
update is enabled.

v1: updated patch description and some explanation and todo

Signed-off-by: Vinod Govindapillai <[e-mail]>
---
 drivers/gpu/drm/i915/display/intel_fbc.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

Patch

diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c b/drivers/gpu/drm/i915/display/intel_fbc.c
index b6978135e8ad..92b00da4c0ab 100644
--- a/drivers/gpu/drm/i915/display/intel_fbc.c
+++ b/drivers/gpu/drm/i915/display/intel_fbc.c
@@ -1464,13 +1464,15 @@  static int intel_fbc_check_plane(struct intel_atomic_state *state,
 	 * Recommendation is to keep this combination disabled
 	 * Bspec: 50422 HSD: 14010260002
 	 *
-	 * In Xe3, PSR2 selective fetch and FBC dirty rect feature cannot
-	 * coexist. So if PSR2 selective fetch is supported then mark that
-	 * FBC is not supported.
-	 * TODO: Need a logic to decide between PSR2 and FBC Dirty rect
+	 * TODO: Implement a logic to select between PSR2 selective fetch and
+	 * FBC based on Bspec: 68881 in xe2lpd onwards.
+	 *
+	 * As we still see some strange underruns in those platforms while
+	 * disabling PSR2, keep FBC disabled in case of selective update is on
+	 * until the selection logic is implemented.
 	 */
-	if ((IS_DISPLAY_VER(display, 12, 14) || HAS_FBC_DIRTY_RECT(display)) &&
-	    crtc_state->has_sel_update && !crtc_state->has_panel_replay) {
+	if (DISPLAY_VER(display) >= 12 && crtc_state->has_sel_update &&
+	    !crtc_state->has_panel_replay) {
 		plane_state->no_fbc_reason = "PSR2 enabled";
 		return 0;
 	}