On Thu, Oct 14, 2021 at 02:21:43PM -0700, Nick Desaulniers wrote:
On Thu, Oct 14, 2021 at 2:19 PM Nathan Chancellor nathan@kernel.org wrote:
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.
Sure, why not.
Link: https://github.com/ClangBuiltLinux/linux/issues/1473 Reported-by: Nick Desaulniers ndesaulniers@google.com
Thanks for the patch! Suggested-by: Dávid Bolvanský david.bolvansky@gmail.com Reviewed-by: Nick Desaulniers ndesaulniers@google.com
Thanks for the patch+review. Applied to drm-intel-next.
Signed-off-by: Nathan Chancellor nathan@kernel.org
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 f90fe39cf8ca..aaa3a0998e4c 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -3050,9 +3050,9 @@ 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;base-commit: d73b17465d6da0a94bc0fcc86b150e1e923e8f71
2.33.1.637.gf443b226ca
-- Thanks, ~Nick Desaulniers