| Message ID | 20211014211916.3550122-1-nathan@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/i915: Avoid bitwise vs logical OR warning in snb_wm_latency_quirk() | expand |
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. > > 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> > 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 >
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
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;
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> --- drivers/gpu/drm/i915/intel_pm.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) base-commit: d73b17465d6da0a94bc0fcc86b150e1e923e8f71