[Intel-gfx] [PATCH 3/3] drm/i915: Fix plane watermark mismatches

[José Roberto de Souza]

Found a system were firmware/BIOS left the plane_res_b and plane_res_l
set with non-zero values for disable planes.
As the planes are disabled i915 will not even try to sanitize it so
here returning earlier if both skl_wm_levels being compared are
disabled, if that is true no need to check the other fields as HW
will ignore it.

Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
---
 drivers/gpu/drm/i915/intel_pm.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 8cc67f9c4e58..c630dc10c34b 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -5633,6 +5633,8 @@ void skl_write_cursor_wm(struct intel_plane *plane,
 bool skl_wm_level_equals(const struct skl_wm_level *l1,
 			 const struct skl_wm_level *l2)
 {
+	if (l1->plane_en == false && l2->plane_en == false)
+		return true;
 	return l1->plane_en == l2->plane_en &&
 		l1->ignore_lines == l2->ignore_lines &&
 		l1->plane_res_l == l2->plane_res_l &&
-- 
2.30.1