From: Nathan Chancellor nathan@kernel.org
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@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-natha... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 @@ -3063,9 +3063,9 @@ 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;