From b8449c43c95b5ea40ced8824d4ddea997f77b911 Mon Sep 17 00:00:00 2001 From: Young Xiao Date: Mon, 17 Dec 2018 12:23:03 +0000 Subject: [PATCH] drm/i915: avoid division by zero on skl_calc_wrpll_link 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. See commit 0e005888b833 ("drm/i915: avoid division by zero on cnl_calc_wrpll_link") for detail. Signed-off-by: Young Xiao Signed-off-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/SG2PR01MB2169F6E95BC8BB5E29477042ADBC0@SG2PR01MB2169.apcprd01.prod.exchangelabs.com --- 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 fdf57f451b72..2d6ed990a232 100644 --- a/drivers/gpu/drm/i915/intel_ddi.c +++ b/drivers/gpu/drm/i915/intel_ddi.c @@ -1296,6 +1296,9 @@ static int skl_calc_wrpll_link(struct drm_i915_private *dev_priv, dco_freq += (((cfgcr1_val & DPLL_CFGCR1_DCO_FRACTION_MASK) >> 9) * 24 * 1000) / 0x8000; + if (WARN_ON(p0 == 0 || p1 == 0 || p2 == 0)) + return 0; + return dco_freq / (p0 * p1 * p2 * 5); } -- 2.30.2