drm/i915: Avoid bitwise vs logical OR warning in snb_wm_latency_quirk()

stable inclusion
from stable-v5.10.92
commit 66d21c005d9beaf874e466d63538ed37aa153c5e
bugzilla: 186193 https://gitee.com/openeuler/kernel/issues/I53108

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=66d21c005d9beaf874e466d63538ed37aa153c5e

--------------------------------

commit 2e705706 upstream.

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/1473Reported-by: NNick Desaulniers <ndesaulniers@google.com>
Signed-off-by: NNathan Chancellor <nathan@kernel.org>
Suggested-by: NDávid Bolvanský <david.bolvansky@gmail.com>
Reviewed-by: NNick Desaulniers <ndesaulniers@google.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211014211916.3550122-1-nathan@kernel.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

drivers/gpu/drm/i915/intel_pm.c

@@ -3044,9 +3044,9 @@ 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;