From: Young Xiao Date: Mon, 17 Dec 2018 12:23:03 +0000 (+0000) Subject: drm/i915: avoid division by zero on skl_calc_wrpll_link X-Git-Tag: v5.4-rc1~1388^2~28^2~52 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b8449c43c95b5ea40ced8824d4ddea997f77b911;p=platform%2Fkernel%2Flinux-rpi.git 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 --- 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); }