On 2018-08-02 04:06 AM, Michel Dänzer wrote: > On 2018-08-01 09:51 PM, Harry Wentland wrote: >> [Why] >> Some boards seem to have a problem where HPD is high on HDMI even though >> no display is connected. We don't want to report these as connected. DP >> spec still requires us to report DP displays as connected when HPD is >> high but we can't read the EDID in order to go to fail-safe mode. >> >> [How] >> If connector_signal is not DP abort detection if we can't retrieve the >> EDID. >> >> Bugzilla: https://bugs.freedesktop.org/107390 >> Bugzilla: https://bugs.freedesktop.org/106846 >> Cc: sta...@vger.kernel.org >> Signed-off-by: Harry Wentland <harry.wentl...@amd.com> >> Acked-by: Alex Deucher <alexander.deuc...@amd.com> >> >> v2: Add Bugzilla and stable >> --- >> drivers/gpu/drm/amd/display/dc/core/dc_link.c | 11 +++++++++++ >> 1 file changed, 11 insertions(+) >> >> diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link.c >> b/drivers/gpu/drm/amd/display/dc/core/dc_link.c >> index b180197a41e2..84f0fd15be4c 100644 >> --- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c >> +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c >> @@ -744,6 +744,17 @@ bool dc_link_detect(struct dc_link *link, enum >> dc_detect_reason reason) >> break; >> case EDID_NO_RESPONSE: >> DC_LOG_ERROR("No EDID read.\n"); >> + >> + /* >> + * Abort detection for non-DP connectors if we have >> + * no EDID >> + * >> + * DP needs to report as connected if HDP is high >> + * even if we have no EDID in order to go to >> + * fail-safe mode >> + */ >> + if (!dc_is_dp_signal(link->connector_signal)) >> + return false; >> default: >> break; >> } >> > > Could this be problematic with VGA connectors? AFAIR e.g. KVM switches > can cause trouble with retrieving EDID, or it could just be an old CRT > with no EDID in the first place. >
Good point, although DC doesn't currently support VGA. I'll send another patch anyways in case anyone enables VGA in the future as this would be easily missed. Harry > Might it make sense to limit this to HDMI & DVI? > > _______________________________________________ amd-gfx mailing list amd-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/amd-gfx
