Commit b8449c43 authored by Young Xiao's avatar Young Xiao Committed by Jani Nikula

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 0e005888 ("drm/i915: avoid division by zero on
cnl_calc_wrpll_link") for detail.
Signed-off-by: default avatarYoung Xiao <YangX92@hotmail.com>
Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/SG2PR01MB2169F6E95BC8BB5E29477042ADBC0@SG2PR01MB2169.apcprd01.prod.exchangelabs.com
parent 68792168
......@@ -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);
}
......
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