On Tue, 21 Jan 2020, Lee Shawn C <[email protected]> wrote: > According to chapter 5.1.1.2 in DP spec. When the Sink > device capability is unknown, for example due to corruption > of an EDID. The Source device may fall back to a set of > fall-back video timing formats its choice. When none of > the fall-back video timing formats is acceptable, the > Source device must fall back to the fail safe mode, > which is 640 x 480 at 60Hz. > > This change set source driver output fail-safe mode automatically > if EDID corrupt. It may also benefit link layer compliance > test case "4.2.2.6 EDID Corruption Detection".
Are you fixing a real user visible bug here, trying to pass compliance tests, or just trying harder to comply with the spec? I am wondering under what circumstances we could actually display a 640x480 image when everything else fails. BR, Jani. > > Cc: Manasi Navare <[email protected]> > Cc: Ville Syrjälä <[email protected]> > Cc: Jani Nikula <[email protected]> > Cc: Cooper Chiou <[email protected]> > Signed-off-by: Lee Shawn C <[email protected]> > --- > drivers/gpu/drm/i915/display/intel_dp.c | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c > b/drivers/gpu/drm/i915/display/intel_dp.c > index c27d3e7ac219..7e072db4a530 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp.c > +++ b/drivers/gpu/drm/i915/display/intel_dp.c > @@ -5659,9 +5659,18 @@ intel_dp_get_edid(struct intel_dp *intel_dp) > return NULL; > > return drm_edid_duplicate(intel_connector->edid); > - } else > - return drm_get_edid(&intel_connector->base, > + } else { > + struct edid *edid; > + > + edid = drm_get_edid(&intel_connector->base, > &intel_dp->aux.ddc); > + > + if (intel_connector->base.edid_corrupt || !edid) > + if (drm_add_modes_noedid(&intel_connector->base, 640, > 480)) > + drm_set_preferred_mode(&intel_connector->base, > 640, 480); > + > + return edid; > + } > } > > static void -- Jani Nikula, Intel Open Source Graphics Center _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
