On Thu, Feb 04, 2021 at 12:18:40PM +0530, Ankit Nautiyal wrote: > DP-HDMI2.1 PCON has DSC encoder caps defined in registers 0x92-0x9E. > Do not read the registers if DPCD rev < 1.4. > > Fixes: https://gitlab.freedesktop.org/drm/intel/-/issues/2868 > Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx> > --- > drivers/gpu/drm/i915/display/intel_dp.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c > index 8c12d5375607..2b83f0f433a2 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp.c > +++ b/drivers/gpu/drm/i915/display/intel_dp.c > @@ -2489,9 +2489,11 @@ static void intel_dp_get_pcon_dsc_cap(struct intel_dp *intel_dp) > struct drm_i915_private *i915 = dp_to_i915(intel_dp); > > /* Clear the cached register set to avoid using stale values */ > - > memset(intel_dp->pcon_dsc_dpcd, 0, sizeof(intel_dp->pcon_dsc_dpcd)); > > + if (intel_dp->dpcd[DP_DPCD_REV] < 0x14) > + return; > + Can't check the spec, but makes sense that this stuff is only valid for recent DCPD revisions. Acked-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > if (drm_dp_dpcd_read(&intel_dp->aux, DP_PCON_DSC_ENCODER, > intel_dp->pcon_dsc_dpcd, > sizeof(intel_dp->pcon_dsc_dpcd)) < 0) > -- > 2.29.2 -- Ville Syrjälä Intel _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
