From b0a088d1d527967cd7933e0364bb18b50017bc37 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
Date: Wed, 24 Nov 2021 13:36:33 +0200
Subject: drm/i915/fbc: Eliminate racy intel_fbc_is_active() usage
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Git-commit: 248e251567a013c960d08124a4abcfc3e2ce6371
Patch-mainline: v5.17-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
The ilk fbc watermark computation uses intel_fbc_is_active() which
is racy since we don't know whether FBC will be enabled or not at
some point. So let's just assume it will be if both HAS_FBC()
and the modparam agree.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211124113652.22090-2-ville.syrjala@linux.intel.com
Reviewed-by: Mika Kahola <mika.kahola@intel.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/i915/intel_pm.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 408fe891a2af..fe3787425780 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3369,13 +3369,8 @@ static void ilk_wm_merge(struct drm_i915_private *dev_priv,
}
/* ILK: LP2+ must be disabled when FBC WM is disabled but FBC enabled */
- /*
- * FIXME this is racy. FBC might get enabled later.
- * What we should check here is whether FBC can be
- * enabled sometime later.
- */
- if (DISPLAY_VER(dev_priv) == 5 && !merged->fbc_wm_enabled &&
- intel_fbc_is_active(&dev_priv->fbc)) {
+ if (DISPLAY_VER(dev_priv) == 5 && HAS_FBC(dev_priv) &&
+ dev_priv->params.enable_fbc && !merged->fbc_wm_enabled) {
for (level = 2; level <= max_level; level++) {
struct intel_wm_level *wm = &merged->wm[level];
--
2.38.1