If for some unexpected reason the registers all read zero it's better to WARN and return instead of dividing by zero and completely freezing the machine. I don't expect this to happen in the wild with the current code, but I accidentally triggered the division by zero while doing some debugging in an unusual environment. Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> Signed-off-by: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx> --- drivers/gpu/drm/i915/intel_ddi.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c index f7c91bb..be86eb6 100644 --- a/drivers/gpu/drm/i915/intel_ddi.c +++ b/drivers/gpu/drm/i915/intel_ddi.c @@ -1220,6 +1220,9 @@ static int cnl_calc_wrpll_link(struct drm_i915_private *dev_priv, dco_freq += (((cfgcr0 & DPLL_CFGCR0_DCO_FRACTION_MASK) >> DPLL_CFGCR0_DCO_FRACTION_SHIFT) * ref_clock) / 0x8000; + if (WARN_ON(p0 == 0 || p1 == 0 || p2 == 0)) + return 0; + return dco_freq / (p0 * p1 * p2 * 5); } -- 2.9.5 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
