From 154877800612468351e876200c0d31668aa5d572 Mon Sep 17 00:00:00 2001
From: Nathan Chancellor <nathan@kernel.org>
Date: Thu, 14 Oct 2021 14:19:16 -0700
Subject: drm/i915: Avoid bitwise vs logical OR warning in
 snb_wm_latency_quirk()
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Git-commit: 2e70570656adfe1c5d9a29940faa348d5f132199
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

A new warning in clang points out a place in this file where a bitwise
OR is being used with boolean types:

drivers/gpu/drm/i915/intel_pm.c:3066:12: warning: use of bitwise '|' with boolean operands [-Wbitwise-instead-of-logical]
        changed = ilk_increase_wm_latency(dev_priv, dev_priv->wm.pri_latency, 12) |
                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This construct is intentional, as it allows every one of the calls to
ilk_increase_wm_latency() to occur (instead of short circuiting with
logical OR) while still caring about the result of each call.

To make this clearer to the compiler, use the '|=' operator to assign
the result of each ilk_increase_wm_latency() call to changed, which
keeps the meaning of the code the same but makes it obvious that every
one of these calls is expected to happen.

Link: https://github.com/ClangBuiltLinux/linux/issues/1473
Reported-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Suggested-by: Dávid Bolvanský <david.bolvansky@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211014211916.3550122-1-nathan@kernel.org
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/i915/intel_pm.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index ecbb3d141632..201477ca408a 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3062,9 +3062,9 @@ static void snb_wm_latency_quirk(struct drm_i915_private *dev_priv)
 	 * The BIOS provided WM memory latency values are often
 	 * inadequate for high resolution displays. Adjust them.
 	 */
-	changed = ilk_increase_wm_latency(dev_priv, dev_priv->wm.pri_latency, 12) |
-		ilk_increase_wm_latency(dev_priv, dev_priv->wm.spr_latency, 12) |
-		ilk_increase_wm_latency(dev_priv, dev_priv->wm.cur_latency, 12);
+	changed = ilk_increase_wm_latency(dev_priv, dev_priv->wm.pri_latency, 12);
+	changed |= ilk_increase_wm_latency(dev_priv, dev_priv->wm.spr_latency, 12);
+	changed |= ilk_increase_wm_latency(dev_priv, dev_priv->wm.cur_latency, 12);
 
 	if (!changed)
 		return;
-- 
2.38.1