| Message ID | SG2PR01MB2169F6E95BC8BB5E29477042ADBC0@SG2PR01MB2169.apcprd01.prod.exchangelabs.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/i915: avoid division by zero on skl_calc_wrpll_link | expand |
On Mon, 17 Dec 2018, Yang Xiao <YangX92@hotmail.com> wrote: > From: Young Xiao <YangX92@hotmail.com> > > 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 <YangX92@hotmail.com> Pushed to drm-intel-next-queued, thanks for the patch. BR, Jani. > --- > 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 5186cd7..cfa7d6f 100644 > --- a/drivers/gpu/drm/i915/intel_ddi.c > +++ b/drivers/gpu/drm/i915/intel_ddi.c > @@ -1360,6 +1360,9 @@ 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); > }
diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c index 5186cd7..cfa7d6f 100644 --- a/drivers/gpu/drm/i915/intel_ddi.c +++ b/drivers/gpu/drm/i915/intel_ddi.c @@ -1360,6 +1360,9 @@ 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); }