On Wed, 14 Oct 2015, Dave Gordon <david.s.gordon@xxxxxxxxx> wrote: > On 17/09/15 14:20, Damien Lespiau wrote: >> Not the first time! not the last time? >> >> There is a possibility to use gcc 5's -Wbool-compare to try and compare >> (reg) in those macros to a constant and gcc will warn that the >> comparison between a boolean expression and a constant is always either >> true or false. Maybe. > > Since boolean true (1) cannot be a valid argument to this macro, it > could contain a compile-time check that the parameter is not 1; if > boolean false (0) happens not to be a valid register address (BSpec says > MMIO 0 is reserved) the macro could check that the argument is neither > of these values, and the compiler might then detect that all possible > paths lead to a compile-time error. Something like this? The past errors have also been of the form if (I915_READ(SOME_REG(pipe) & MASK) == val) which isn't caught by your check. See [1]. BR, Jani. [1] http://mid.gmane.org/1442595836-23981-1-git-send-email-ville.syrjala@xxxxxxxxxxxxxxx > > #define I915_READ(reg) \ > ({ \ > if (__builtin_constant_p(reg)) { \ > BUILD_BUG_ON((reg) == false); \ > BUILD_BUG_ON((reg) == true); \ > } \ > dev_priv->uncore.funcs.mmio_readl(dev_priv, (reg), true); \ > }) > > Interestingly, that reported three errors, all in intel_dsi.c where the > port-selection macros use 0s to fill in dummy elements when less than 3 > ports are being used. > > In function ‘intel_dsi_get_hw_state’ > In function ‘intel_dsi_port_disable’ > In function ‘intel_dsi_port_enable’ > > Other than that, there weren't any cases where a bool constant was being > passed to this specific macro (as of today). > > .Dave. > >> Cc: Imre Deak <imre.deak@xxxxxxxxx> >> Signed-off-by: Damien Lespiau <damien.lespiau@xxxxxxxxx> >> --- >> drivers/gpu/drm/i915/intel_ddi.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c >> index 4823184..5b600bf 100644 >> --- a/drivers/gpu/drm/i915/intel_ddi.c >> +++ b/drivers/gpu/drm/i915/intel_ddi.c >> @@ -2882,7 +2882,7 @@ static bool bxt_ddi_pll_get_hw_state(struct drm_i915_private *dev_priv, >> * here just read out lanes 0/1 and output a note if lanes 2/3 differ. >> */ >> hw_state->pcsdw12 = I915_READ(BXT_PORT_PCS_DW12_LN01(port)); >> - if (I915_READ(BXT_PORT_PCS_DW12_LN23(port) != hw_state->pcsdw12)) >> + if (I915_READ(BXT_PORT_PCS_DW12_LN23(port)) != hw_state->pcsdw12) >> DRM_DEBUG_DRIVER("lane stagger config different for lane 01 (%08x) and 23 (%08x)\n", >> hw_state->pcsdw12, >> I915_READ(BXT_PORT_PCS_DW12_LN23(port))); > > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > http://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
