From 8d6e41fc9b5194fb24523c939de54a2af46b5d07 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20=C3=85dahl?= <jadahl@gmail.com>
Date: Fri, 27 May 2022 18:19:27 +0200
Subject: [PATCH] kms/crtc: Determine gamma support given the gamma length

The property doesn't necessarily exist when using drivers that doesn't
support atomic mode setting, and the way it worked will break night
light and other gamma related features. This makes things use the gamma
length; if it is higher than 0, it definitely supports it one way or the
other, i.e. GAMMA_LUT with the atomic backend, and drmModeCrtcSetGamma()
with the legacy/simple backend.

Fixes: 364572b95c8354ac66674064a8058aa98bc0bbef
Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/2287
(cherry picked from commit a2ebd10f049d888e451938e23a035ed97e0c8eff)

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2452>
---
 src/backends/native/meta-kms-crtc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/backends/native/meta-kms-crtc.c b/src/backends/native/meta-kms-crtc.c
index 24f5a2d7400..0513af947c9 100644
--- a/src/backends/native/meta-kms-crtc.c
+++ b/src/backends/native/meta-kms-crtc.c
@@ -96,7 +96,7 @@ meta_kms_crtc_is_active (MetaKmsCrtc *crtc)
 gboolean
 meta_kms_crtc_has_gamma (MetaKmsCrtc *crtc)
 {
-  return !!meta_kms_crtc_get_prop_id (crtc, META_KMS_CRTC_PROP_GAMMA_LUT);
+  return crtc->current_state.gamma.size > 0;
 }
 
 static void
-- 
2.36.1