[Intel-gfx] [PATCH] drm/i915: Only call skl_check_plane_surface() for visible planes

[Matt Roper]

When a plane is fully clipped (either because it's positioned offscreen,
or because the CRTC is currently off), the clipping calculations we do
during check_plane will leave nonsense/negative coordinates in plane's
source rectangle.  This is generally harmless since we recognize that
the plane should be turned off and we don't try to actually do anything
with those values.  However on gen9 platforms, we still try to do
surface offset math in skl_check_plane_surface() which gets confused and
reports "Unable to find suitable display surface offset."  Given that
the plane will be disabled anyway, none of these calculations are
actually necessary, so just skip calling the function on non-visible
planes.

Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Fixes: b63a16f6cd ("drm/i915: Compute display surface offset in the plane check hook for SKL+")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=98258
Testcase: igt/pm_rpm/legacy-planes
Testcase: igt/pm_rpm/universal-planes
Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
---
There may be additional IGT tests (e.g., in kms_plane) that also trip over
this.  I only listed the two that I was using for debugging when I tracked this
down.

 drivers/gpu/drm/i915/intel_display.c | 2 +-
 drivers/gpu/drm/i915/intel_sprite.c  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 0a38de9..9295f8a 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -15149,7 +15149,7 @@ intel_check_primary_plane(struct drm_plane *plane,
 	if (!state->base.fb)
 		return 0;
 
-	if (INTEL_GEN(dev_priv) >= 9) {
+	if (INTEL_GEN(dev_priv) >= 9 && state->base.visible) {
 		ret = skl_check_plane_surface(state);
 		if (ret)
 			return ret;
diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c
index ada8f7a..5cedea4 100644
--- a/drivers/gpu/drm/i915/intel_sprite.c
+++ b/drivers/gpu/drm/i915/intel_sprite.c
@@ -967,7 +967,7 @@ intel_check_sprite_plane(struct drm_plane *plane,
 	dst->y1 = crtc_y;
 	dst->y2 = crtc_y + crtc_h;
 
-	if (INTEL_GEN(dev) >= 9) {
+	if (INTEL_GEN(dev) >= 9 && state->base.visible) {
 		ret = skl_check_plane_surface(state);
 		if (ret)
 			return ret;
-- 
2.10.2