From 55e5ad88c5f9beba7ebf609521eae56675d01fa1 Mon Sep 17 00:00:00 2001
From: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Date: Wed, 20 May 2020 17:58:27 +0300
Subject: drm/i915: Check plane configuration properly
Git-commit: 9877c37e05c8428ed80cc9652d41322ff5fa59ed
Patch-mainline: v5.9-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322
Checking with hweight8 if plane configuration had
changed seems to be wrong as different plane configs
can result in a same hamming weight.
So lets check the bitmask itself.
v2: Fixed "from" field which got corrupted for some weird reason
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200520145827.15887-1-stanislav.lisovskiy@intel.com
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/i915/display/intel_display.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 15eb7f32844a..dd776ba8b358 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -14697,7 +14697,13 @@ static int intel_atomic_check_planes(struct intel_atomic_state *state)
old_active_planes = old_crtc_state->active_planes & ~BIT(PLANE_CURSOR);
new_active_planes = new_crtc_state->active_planes & ~BIT(PLANE_CURSOR);
- if (hweight8(old_active_planes) == hweight8(new_active_planes))
+ /*
+ * Not only the number of planes, but if the plane configuration had
+ * changed might already mean we need to recompute min CDCLK,
+ * because different planes might consume different amount of Dbuf bandwidth
+ * according to formula: Bw per plane = Pixel rate * bpp * pipe/plane scale factor
+ */
+ if (old_active_planes == new_active_planes)
continue;
ret = intel_crtc_add_planes_to_state(state, crtc, new_active_planes);
--
2.29.2