[PATCH v2] drm/atomic: Add the crtc to affected crtc only if uapi.enable = true

[Manasi Navare]

In case of a modeset where a mode gets split across mutiple CRTCs
in the driver specific implementation (bigjoiner in i915) we wrongly count
the affected CRTCs based on the drm_crtc_mask and indicate the stolen CRTC as
an affected CRTC in atomic_check_only().
This triggers a warning since affected CRTCs doent match requested CRTC.

To fix this in such bigjoiner configurations, we should only
increment affected crtcs if that CRTC is enabled in UAPI not
if it is just used internally in the driver to split the mode.

There is no way we can adjust requested_crtc calculation as suggested
in review comments because the crtc gets stolen only after the atomic_check call.

Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Simon Ser <contact at emersion.fr>
Cc: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
Cc: Daniel Stone <daniels at collabora.com>
Cc: Daniel Vetter <daniel.vetter at intel.com>
Cc: dri-devel at lists.freedesktop.org
Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
---
 drivers/gpu/drm/drm_atomic.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index ff1416cd609a..44e7ebf43a2a 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -1360,8 +1360,10 @@ int drm_atomic_check_only(struct drm_atomic_state *state)
 		}
 	}
 
-	for_each_new_crtc_in_state(state, crtc, new_crtc_state, i)
-		affected_crtc |= drm_crtc_mask(crtc);
+	for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) {
+		if (new_crtc_state->enable)
+			affected_crtc |= drm_crtc_mask(crtc);
+	}
 
 	/*
 	 * For commits that allow modesets drivers can add other CRTCs to the
-- 
2.19.1