This is a note to let you know that I've just added the patch titled
drm/i915: Avoid bitwise vs logical OR warning in snb_wm_latency_quirk()
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-i915-avoid-bitwise-vs-logical-or-warning-in-snb_wm_latency_quirk.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2e70570656adfe1c5d9a29940faa348d5f132199 Mon Sep 17 00:00:00 2001
From: Nathan Chancellor <nathan@xxxxxxxxxx>
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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From: Nathan Chancellor <nathan@xxxxxxxxxx>
commit 2e70570656adfe1c5d9a29940faa348d5f132199 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/1473
Reported-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Suggested-by: Dávid Bolvanský <david.bolvansky@xxxxxxxxx>
Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20211014211916.3550122-1-nathan@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_pm.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -2245,9 +2245,9 @@ static void snb_wm_latency_quirk(struct
* 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;
Patches currently in stable-queue which might be from nathan@xxxxxxxxxx are
queue-4.4/drm-i915-avoid-bitwise-vs-logical-or-warning-in-snb_wm_latency_quirk.patch
